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' ‘3‘ ' o . r '- - 7-5... — ., - ,- ._ ru‘" ; . ~- _~ _..‘_. — . ‘ . . “ .- . - 0 a -. .o - .t V- w IIML‘, _ ’3‘ no” .. - Mo. ._ 'n 1 '71:. ‘ .J. low. fang: \ v... ., 5‘2“" {E . “I. I “I‘- F13 33 3F .. ,- 5153”}! ":1“ ”1313 ,, .'?3':F 33F: “F173 33.313331. 1%“? lll’iimli'mfl’ilmm}mullflflli’tiun'flfii‘lfilflfiu 3 1293 00074 3884 LIBRARY Michigan State J. University This is to certify that the dissertation entitled AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAGES UTILIZING INTERACTIVE COMPUTER GRAPHICS presented by DENNIS GENE WATSON has been accepted towards fulfillment of the requirements for Doctor ofiEhileophydegree in Aqricultural Engineering Technology, Department of Agriculture Engineering ofessor Date <9 9 A 11C? (3 7 {J MSU i: an Affirmative Action/Equal Opportunity Institution 012771 “‘— A MSU RETURNING MATERIALS: Place in book drop to LIBRARJES remove this checkout from up. your Y‘ECOY‘d. FINES Will be charged if book is returned after the date stamped below. . n “I"? t N "' , .- 1 AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAG ES UTILIZING INTERACTIVE COMPUTER GRAPHICS BY Dennis Gene Watson A DISSERTATION Submitted to Michigan State University in partial fufillment of the requirements for the degree oi DOCTOR OF PHILOSOPHY in Agricultural Engineering Technology Department of Agricultural Engineering 1 987 Copyright by DENNIS GENE WATSON 1987 AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAGES UTILIZING INTERACTIVE COMPUTER GRAPHICS BY Dennis Gene Watson AN ABSTRACT OF A DISSERTATION Submitted to Michigan State University in partial tuflllment of the requirements for the degree of DOCTOR OF PHILOSOPHY in Agricultural Engineering Technology Department of Agricultural Engineering 1 987 T SIOIE liliz A engir 9X99} prowl mariaI impler the K31 deSCr: Ba. Specn; SYSterT COnSCI DIaCEP mgher. I I preparl I l Compar ABSTRACT AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAG ES UTILIZING INTERACTIVE COMPUTER GRAPHICS BY Dennis Gene Watson The goal of this research was to study aeration system design for flat grain storages and implement and evaluate an aeration system design program utilizing interactive computer graphics. A set of software tools was synthesized for development of agricultural engineering design programs. This development system was modeled after an expert's problem solving process for design applications and divides a computer program into components of interview, calculations, design drawing and management recommendations. A group of software tools suitable for implementing each component of the development system was presented and the tools used to implement the aeration system design program were described. Based on user responses to questions about a grain storage. the program prepares paper copy of a floor plan of the duct layout, a list of component specifications and a list of management recommendations for the user. Aeration system design guidelines and recommendations from various sources were consolidated into a set of guidelines for use in the computer program. The placement of ducts was accomplished with a modified air path ratio method. A higher air path ratio was used to place a duct from an outer wall of a storage compared to placement in the center of a storage. This method results in duct placement similar to methods which base the number and placement of ducts on the size of the storage. l0 dUl Wa: mic Dennis Gene Watson A stmctured review process was used to evaluate the aeration system design program. Nine extension specialists and industry representatives evaluated technical and usability aspects of the program. Technical content was evaluated for concurrent validity, construct validity, content validity and sensitivity. Usability evaluation centered on ease of use, information conveyance, pertinence of illustrations and usefulness of the design drawing and management recommendations. Differences were found between results generated by the computer program and the reviewers. The difference in problem solutions is a function of variation in the reviewers' preferred guidelines. Two areas of difference are the distance to offset a perforated duct from the edge of a storage and the maximum length of duct to allow from an air source. Results of the usability evaluation were very favorable. The user interface was rated very easy to use and was recommended for use by beginning microcomputer users, county extension agents and farmers. Approved E314” ( ’L‘T‘CQ‘ Major Professor Approved Department Chairperson To my wife and childen ACKNOWLEDGMENTS Several people have contributed to this work and I would like to take this opportunity to express my appreciation and acknowledge their efforts. I would like to express appreciation to Dr. Roger Brook, my major professor, for his guidance, encouragement and support throughout my graduate studies. His experience and suggestions were especially beneficial during development of the aeration system design program I am grateful to Drs. Mary Andrews, William Bickert, Erik Goodman and Steve Harsh for agreeing to serve on my graduate committee. Their assistance and professional review throughout this project have been of great value, i would like to express my appreciation to the W. K. Kellogg Foundation staff for providing the resources needed to conduct this study. Their foresight in funding a project to demonstrate computer graphics as a vehicle for providing human services is to be commended. Gary Peterson was very instrumental throughout this project. His diligence in providing and maintaining the computer equipment, willingness to discuss any aspects of the project on a moment's notice, and friendship are especially appreciated. Ken Kuck was very helpful in developing and testing many of the algorithms for the calculations component of the aeration system design program. The participation of George Foster and Bruce McKenzie of Purdue University; Marvin Hall, William Peterson and Gene Shove of University of lllinois; Bill vi Alterrnatt and Joe McNall of Hancor, Inc. and Dan Hansen and Stephanie Ganser of Aerovent Fan and Equipment, Inc. during the technical and usability evaluation process is greatly appreciated. I would also like to express great appreciation to my wife, Marva, and children for their perseverance, understanding and support during the long hours of my graduate program. vii TABLE OF CONTENTS LIST OF TABLES - LIST OF FIGURES CHAPTER I. INTRODUCTION GOAL AND OBJECTIVES - - ll. AERATION SYSTEM DESIGN GUIDELINES AERATION EQUIPMENT FANS . . . . . . . DUCTS- . . . . . . . . . SUPPLY TUBES AND CONNECTORS SYSTEM DESIGN CONSIDERATIONS AlRFLOW DIRECTION ' - AIRFLOW RATE DESIGN PROCEDURE - SIZING COMPONENTS - STORAGE CAPACITY DUCT PLACEMENT Level Filled Storages Peak Loaded Storages Duct End Points FAN SIZING DUCT SIZING - Diameter - Length - SUPPLY TUBE SIZING EXHAUST AREA SIZING viii Page xii xiv mVVNO'IO'lUI-hwd NNNNNA—L—A—L—L-J‘ A-hOD—AACDNOIUIQ-A—tto TABLE OF CONTENTS (Contlnued) P III. DEVELOPMENT SYSTEM FOR AGRICULTURAL DESIGN age PROGRAMS - - - - . . 26 COMPONENTS OF DEVELOPMENT SYSTEM - - - - - - 27 |NTERV|EW . . . . . . . . . . . . . . . 27 CALCULAT|QNS . . . . . . . . . . . . . . 23 DESIGN DRAWING - - - - - - - - - - - - - 30 MANAGEMENT RECOMMENDATIONS - - - - - - - 33 FRAMEWORK . . . . . . . ' . . . . . . . . 34 SOFTWARE TOOLS FOR DEVELOPMENT SYSTEM - - - - 35 INTERVIEW . . . . . . . . . . . . . . . 37 CALCULATIONS . . . . . . . . . . . . . . 33 DESIGN DRAWING - - - - - - ° - - - - - - 38 MANAGEMENT RECOMMENDATIONS - - - - - - - 39 FRAMEWORK . . . . . . . . . . . . . . . 41 IV. AERATION SYSTEM DESIGN PROGRAM - - - - ~ - - - 43 INTERVIEW . . ‘. . . . . . . . . . . . . . 43 CALCULATIONS . . . . . . . . . . . . . . . 47 pos'r SIZING . . . . . . . . . . . . . . . 43 STORAGE CAPACITY - - - - - - - - - - - - 49 DUCT PLACEMENT - - - - - - - - ~ - - - - 55 DUCT LENGTH . . . . . . . . . . . . . . 53 FAN PLACEMENT AND SIZE - - - - - - - - - . 59 DUCT SIZE . . . . . . . . . . . . . . . 50 SUPPLY TUBE PLACEMENT AND SIZE - - . - - - - 61 DESIGN DRAWINGS - - - - - - - - - - - ~ - 61 MANAGEMENT RECOMMENDATIONS - - - - - - - - 67 TABLE OF CONTENTS (Continued) V. EVALUATION OF AERATION SYSTEM DESIGN PROGRAM - EVALUATION OBJECTIVES - - TECHNICAL EVALUATION OBJECTIVES - USABILITY EVALUATION OBJECTIVES EVALUATION INSTRUMENTS AND PROCEDURE - EVALUATION INSTRUMENTS - CONTACT WITH REVIEWERS - ON-SITE EVALUATION RESULTS OF EVALUATION TECHNICAL EVALUATION Concurrent Validity - Construct Validity Content Validity - Sensitivity USABILITY EVALUATION IMPLICATIONS OF EVALUATION - TECHNICAL IMPLICATIONS - Construct Considerations - Content Considerations - USABILITY IMPLICATIONS - Vl. SUMMARY AND CONCLUSIONS RECOMMENDATIONS FOR AGRICULTURAL DESIGN PROGRAMS - - RECOMMENDATIONS FOR AERATION SYSTEM DESIGN REFERENCES Page 73 73 73 74 75 75 78 79 80 80 80 85 87 89 92 94 94 94 96 97 99 101 - 101 103 TABLE OF CONTENTS (Contlnued) Page APPENDICES . A. Listing of Interview Text File - - - - - - - - - - - - 106 B. 'C' Source Code for Function to Perform Consistency Checks - - - 121 C. 'C' Source Code for Function to Perform Special Flow Control - - - 122 D. Sample Data File Produced by Interview Component - - - - - 125 E. Sample Data File Produced by Calculations Component - - - ~ 126 F. 'C' Source Code for Function to Write Specification File for Synthesis 128 G. Listing of Management Recommendations Text File - - - - - 132 H. 'C' Source Code of Rules for Printing Management Recommendations 139 I. Information Sheets and Evaluation Instruments Sent to Reviewers BeforeOn-SiteVisit- - - - - - - - - - - - - - - 141 Evaluation Instruments Used During On-Site Evaluation - - - - 155 .‘ Summary of Reviewers' Responses to Questionnaires - - - - - 165 Hardware and Software Requirements for Program - - - - - 181 I'XS- xi 10. 11. 12. 13. 14. LIST OF TABLES Average, minimum and maximum angles of repose for some common grains ' O o o o 0 o o o o o . Values for constants a and b used in airflow resistance equation - Recommended maximum allowable air velocities within ducts installed in flat storages with suction system aeration Recommendations for maximum airflow velocity in ducts - Recommendations for maximum airflow velocity at duct surface . Response screens for aeration system design program Consistency checks for aeration systemdesign program Supplemental flow control for aeration system design program Allowable grain depth for post size and post spacing Master drawings for the aeration system design program Description of worksheets included with case studies - Reviewers for aeration system design program - Agenda for on-site evaluation of aeration system design program Summary of reviewers' ratings of design results - xii Page 13 20 22 23 24 44 46 47 48 63 76 78 79 81 15. 16. 17. 18. 19. LIST OF TABLES (Cont'd) Summary of reviewers' agreement with design guidelines Summary of reviewers' opinions regarding response screens - Improvements to response screens suggested by reviewers - Summary of reviewers' opinions of 'help' information Summary of reviewers' comments on 'help' information xiii Page 86 87 89 90 91 10. 11. 12. LIST OF FIGURES . Typical flat grain storage divided into areas for volume calculation Cross section of grain storage with duct placement to achieve maximum air path ratio of 1.5 - - - - - . - . Aeration duct arrangements for flat storages recommended by Cloud and Morey (1980), Foster and Tuite (1986), Holman (1960) and Midwest Plan Service (1987) - Sample question from interview component, illustrating the necessity of graphics to communicate effectively with a client - - - - Sample customized plan view of an aeration system, representing a design drawing to be provided to a client - - Conceptual relationship of program developer and client with the development system software components - - - - Functional description of Synthesis and AutoCAD usage to produce a parameterized design drawing - - - - - - - . . . Grain storage divisions for volume calculation of flat storage - Sample component specification listing generated by the aeration system design program . . . . BASE master drawing: rectangular outline of grain storage DUCT master drawing: perforated duct to be placed in a drawing FAN master drawing: fan and supply tube to be placed in drawing xiv Page 12 14 18 29 32 36 40 62 64 13. 14. 15. LIST OF FIGURES (cont'd) Partial listing of a drawing specificationI file for an aeration system design..... ....... .. Sample aeration system plan displayed and printed for user of aeration system design program - - . . . Partial listing of management recommendations from an aeration system dQSign o o o o o o o o o o o o o XV Page 68 69 70 CHAPTER I INTRODUCTION The recent grain surplus has resulted in a shortage of storage facilities and a program of government incentives for producers who store grain. Grain producers have responded by preparing new and existing structures for grain storage. Adequate preparation includes the installation of aeration systems to maintain the quality of stored grain. If aeration systems are not properly designed, grain spoilage and economic loss can occur. Design recommendations for aeration systems are readily available in handbooks, bulletins and other reference materials. These materials provide specific recommendations for some parts of an aeration system. Other recommendations are necessarily general and are often not applicable to a producer's specific problem. The knowledge and experience of an expert in aeration system design is needed to adapt general recommendations to specific situations. Unfortunately, the availability of these experts--agricultural engineering extension specialists and consultants-43 often limited. As a result, aeration systems are installed without the benefit of an expert's knowledge. To remedy this situation, a computer program has been developed to simulate the role of an expert in aeration system design in an interactive session with a client (a producer storing grain). an Pr: deg Th, GEI 2 Increased availability of microcomputers for agricultural purposes has led to development of microcomputer application programs for agricultural education, research and extension purposes. Many quality programs of sound technical content have emerged. However, most microcomputer programs rely on textual information to communicate with users, whereas experts in aeration system design rely on visual aids to communicate with clients. In particular they prepare design drawing for clients to use when implementing designs. To supply this visual component, interactive computer graphics technology was used to develop this program. Effective use of computer graphics enhances information transfer between a computer program and client. Computer controlled illustrations communicate concepts when asking questions and custom design drawings are generated as solutions to design problems. Although commercial software products for IBM-compatible microcomputers are available to implement various portions of an agricultural engineering design program, they do not interact directly. To complement the development of computer-aided engineering applications for educational and extension purposes, a software system based on interactive computer graphics was needed. The system had to be flexible enough to incorporate new commercial software products as they become available. A set of suitable software tools was synthesized, to facilitate development of design applications that appear as one program from the user's perspective. The aeration system design program was selected for development and demonstration as a ccmputer—graphics-based design program. anc graI 3 GOAL AND OBJECTIVES The research goal was to study aeration system design for flat grain storages and implement an aeration system design program utilizing interactive computer graphics. Specifically, the objectives were as follows: 1) consolidate design concepts and recommendations for aeration systems in flat grain storages 2) synthesize a set of tools for developing agricultural engineering design programs such as an aeration system design program 3) develop a program to design aeration systems for flat grain storages 4) evaluate the aeration system design program. CHAPTER II AERATION SYSTEM DESIGN GUIDELINES The purpose of this chapter is to review aeration system design literature to determine appropriate guidelines for the design of aeration systems for flat grain storages. Flat storages are defined as any storage where the height of grain is less than the diameter or width (Holman, 1960). Aeration systems are designed to distribute an appropriate volume of air in a reasonably uniform manner throughout a grain mass. Uniformity of airflow is a key design concern. In typical aeration systems for upright storages, the lowest airflow rate in any part of the storage usually is not less than 90 percent of the selected rate. In contrast, in well-designed systems for flat storages, the lowest airflow rate in some portions of the grain may be less than 50 percent of the selected rate (Holman, 1960). This difference in uniformity is due to the lower ratio of duct surface area to floor area common in flat storages. Aeration system design for flat storages is a compromise between airflow uniformity and reasonable costs. This review of aeration system design guidelines is divided into four sections: first, a review of aeration equipment; second, system design considerations; third, a discussion of aeration system design procedure; and fourth, guidelines for sizing components. pun tube FAN shou pedo Sale Consk An axial I; about SSH/IQ fans.] aefafio FIN maCed I Pe”0raf IIIJGS 01 mbmg' 5 AERATION EQUIPMENT The principal parts of an aeration system and their functions are 1) fans to provide airflow; 2) ducts to distribute air throughout a grain mass and 3) supply tubes to connect fans and ducts. FANS Axial and centrifugal fans are commonly used in aeration systems. Fans should be selected based on the manufacturers' performance ratings. Typical performance ratings specify the volume of air delivered by a fan over a range of static pressures. The unique features of axial and centrifugal fans should be considered to determine which type of fan to use. An axial fan houses the fan and motor within the airstream. Generally, an axial fan will deliver more air than a centrifugal fan at static pressures less than about 1 kPa (4 in. H20) (Brook, 1979; Foster and Tuite, 1986; Midwest Plan Service (MWPS ), 1987). Axial fans are usually less expensive than centrifugal fans. They can be easily mounted in circular ducts and are widely used for aeration in farm bins and flat storages. On a centrifugal fan, the motor is mounted outside the air stream. Centrifugal ' fans are recommended for static pressures above 1 kPa (4 in. H20) (Brook, 1979; Foster and Tuite, 1986; Holman, 1960). They are quieter than axial fans and are used where lower noise levels are desired (Foster and Tuite, 1986). DUCTS Flat storages are usually temporary grain storages and aeration ducts are placed directly on the floor. Ducts facilitate air distribution through a grain mass. Perforations in ducts allow air to pass from the duct through the grain. Common types of on-floor ducts are round metal, half-round metal and plastic aeration tubing. gm Un are Hol whl lypll now TIDE (Bax Open W961 Nfidvn bOlIor IWflla least 1 ”arm F”Ian E The a SeCfio AI 99rcer affects genera. DGICQnt in ”at SII 6 A duct material must have enough perforations to allow sufficient air to reach grain while preventing grain from entering the duct (Foster and Tuite, 1986). Uniformly spaced perforations equal to seven to ten percent of the duct surface area were recommended by Cloud and Morey (1980), Foster and Tuite (1986), Holman (1960) and Noyes (1967). Perforated metal aeration ducts are available which have up to twice this percentage of perforations, whereas plastic tubing typically has less open area. Plastic drainage pipe has been used for aeration ducts. Manufacturers are now supplying plastic pipe specifically for this purpose. Plastic drainage pipe typically has perforated areas as small as one percent of the surface area (Brook, 1986), but some perforated plastic aeration tubing has up to six percent open area (Hancor, 1985). Plastic ducts must have enough open area in the pipe wall to allow air to pass through easily (Midwest Plan Service, 1987). Midwest Plan Service (1987) recommended that if the openings are in the bottom of the corrugations and evenly distributed, plastic pipes can be covered with a screen or mesh. The total area of the openings in the pipe wall should at least equal the pipe's cross-sectional area. If the openings in the duct are narrow slots in the bottom of the corrugations (as in plastic drain tile), Midwest Plan Service (1987) did not recommend covering the pipe with screen or mesh. The area of the wall openings should be about three times the duct cross- sectional area (MWPS, 1987). At present, insufficient research data exists to determine how the smaller percentage of open surface area and the corrugated construction of plastic ducts affects airflow through grain as compared to metal ducts. Metal ducts are generally preferred for air distribution in grain storages because at least seven percent of their surface area is open. However, plastic ducts are popular for use in flat storages due to their lower cost and ease of handling. SU per duc duc fanl conn Shou dUCL F II Conne aetatil ”turn dinne 7 SUPPLY TUBES AND CONNECTORS Supply tubes and connectors connect a fan, on the outside of a storage, to a perforated duct, which is offset from the edge of the storage. Supply tubes are ducts without perforations and are usually of the same type as the perforated ducts. Optimal performance of an aeration system will not be achieved unless the fan is properly connected to the duct. Holman (1960) estimated that a poor fan connection may reduce the airflow by 25 percent or more. Air entering a fan should approximate a straight line. Upright storages usually have one fan per duct and the fan can be mounted on the end of the duct without any elbows. Flat storages usually require low airflow per duct and it is cost efficient to connect one fan to multiple ducts. In this case, a fan is often attached to an aeration tube via a tee or elbow fitting. Tees and elbows should be selected to minimize flow restriction. An elbow with a radius of at least 1.5 times the duct diameter is recommended (Holman, 1960). SYSTEM DESIGN CONSIDERATIONS Two primary considerations in the design and operation of an aeration system are the direction of airflow and the rate of airflow. AlRFLOW DIRECTION Aeration distribution systems are classified as either pressure or suction systems. A pressure system pushes air through the grain; a suction system pulls air through the grain. Airflow is generally upward in a pressure system and downward in a suction system. Although one system may be more appropriate in a particular application, either can be used effectively for aeration if equipment is properly installed and managed (Brook and Watson, 1986). Brook and .1. Wats- adval press 1987) sysler top of heat It 1986); measu and Tu its hum Otherwj 1986). A su conden5 WaISOn Storages deIllhs 0 the grain A"‘IFLOI U”l‘for. grain, H0 rate than c to the We 8 Watson (1986), Foster and Tuite (1986) and Holman (1960) discussed the advantages and disadvantages of both system types. Pressure systems have the following advantages for flat storages: (1) positive pressure tends to keep openings in plastic aeration pipe from plugging (MWPS, 1987); (2) upward airflow permits more uniform air distribution than suction systems (Steele and Shove, 1969; Burrell, 1974); (3) heat is moved out of the top of the storage, permitting warm grain to be added to storage without pulling heat through previously cool grain (Brook and Watson, 1986; Foster and Tuite, 1986); (4) completion of an aeration cycle is easily monitored by temperature measurement of the grain near the top surface (Brook and Watson, 1986; Foster and Tuite, 1986) and (5) heat from the fan raises the air temperature and lowers its humidity, thus permitting aeration to proceed at times when the air would otherwise be too cold or humid (Brook and Watson, 1986; Foster and Tuite, 1986) A suction system expels air at a high enough velocity to prevent moisture condensation, which can be a problem with pressure systems (Brook and Watson, 1986; Foster and Tuite, 1986). Aeration can be started in partially filled storages with downward airflow by covering the exposed duct and shallow depths of grain with plastic sheets. Likewise air can be directed to hot spots in the grain mass (Foster and Tuite, 1986). AIRFLOW RATE Uniform airflow is desirable and relates directly to uniform conditioning of grain. However, in most flat storages, some grain is aerated at a higher airflow rate than other portions of the grain mass. Careful consideration must be given to the lowest rate that can be permitted in any portion of the stored grain, as the time required for aeration is determined by the lowest airflow rate. For design purpo. mean: 1960). Air those 13./min bins ar Tuite (' wheat i For 0.16 mi Brook (' 0.? 1% 1131mm mOISIUre 9 purposes, small portions of the grain mass which cool by conduction or other means may be disregarded in determining the lowest airflow rate (Holman, 1960). Airflow rates measured in grain soon after storage usually will be higher than those measured after several months. An airflow rate 010.08 m3/min/m3 (0.1 ft3/min/bu) is widely used to aerate shelled corn and soybeans stored in farm bins and in flat storages (Foster and Tuite, 1986; Noyes, 1967). Foster and Tuite (1986) recommended an airflow of 0.04 m3/min/m3 (0.05 ft3/min/bu) for wheat and other smaller seeded crops. For flat storages, Cloud and Morey (1980) suggested airflow rates of 0.10 to 0.16 m3/min/m3 (0.125 to 0.2 ft3/min/bu) to compensate for less uniform airflow. Brook (1979) recommended a delivered airflow of 0.08 to 0.16 m3/min/m3 (0.1 to 0.2 ft3/min/bu) for dry farm-stored grains. An airflow of 0.08 m3/min/m3 (0.1 ft3/min/bu) is acceptable for clean, dry grain. Grain stored with fines or at a moisture content above the recommended values requires a higher airflow of 0.16 m3/min/m3 (0.20 fl3/min/bu). DESIGN PROCEDURE Aeration systems have often been designed for upright storages. Some published procedures for aeration system design reflect this fact as the number of ducts is a foregone conclusion. The following design procedure described by Peterson (1985) is typical of methods which assume duct placement based upon storage size: 1) determine storage capacity and profile 2) calculate total airflow required 3) determine fan size 4) calculate duct size 5) place duct 10 The above procedure is adequate for upright storages and some flat storages. When used for flat storages, the designer must have good rules of thumb for the appropriate number of ducts and placement of ducts with various grain profiles. This procedure has the potential of resulting in extremely non- uniform airflow unless adjustments are made for the grain depths in the storage. A different procedure is needed for use in a computer program where a wide range of problems will be solved. Burrell (1974) described the following aeration system design procedure: 1) determine storage profile and volume 2) select airflow rate and calculate total airflow 3) determine number and placement of ducts 4) divide total airflow by number of ducts 5) size duct 6) estimate static pressure 7) size fan The design procedure described by Holman (1960) was: 1) determine storage dimensions and capacity 2) select airflow rate 4) estimate volume of grain served by each duct 5) calculate air volume needed for each duct 6) size fan 7) size duct 8) size supply tubes Two major differences exist between the Burrell and Holman methods. Holman estimated the amount of grain served by each duct to determine the airflow required by the duct. Burrell divided the total airflow of the storage evenly among the ducts. Dividing the airflow evenly among the ducts can result in a considerable difference in delivered airflow per unit of grain when the volume served by ducts in the same storage varies considerably. Burrell also advocated sizing the duct first and then the fan, which is the reverse of Holman's method. If airflow velocity is indeed the determining factor in SIZII the du Sizi duct pl: STORA Grai doorwaj four wal. accompl Service ( Calculate both 9nd grain Cap C3398 anr Other presented With Open delith. Hu Conical pile The ink Storage is v ma’II'ITIUm g s’ope of the VOIUme’ but I. grain line, on 11 in sizing a duct, then the fan must be sized first to determine the actual airflow in the duct. SIZING COMPONENTS Sizing aeration system components requires determining storage capacity, duct placement, fan sizes, duct sizes, supply tube sizes and exhaust area. STORAGE CAPACITY Grain in flat storage is typically peaked to increase capacity. Due to doorways and other limitations in buildings, the grain depth may vary among the four walls which retain the grain. Calculation of grain volume can be accomplished by dividing the grain mass into simple shapes. Midwest Plan Service (1987) suggested a typical peaked flat storage building volume can be calculated by dividing it into three volumes of level fill area, triangular peak and both and peaks (Figure 1). The constant of 1.244 fl3/bu is used to determine grain capacity in traditional units (bushels). This procedure Is suitable in most cases and provides a quick approximation. Other means of calculating grain volume are available. Holligan (1982) presented equations for free flowing materials stored in rectangular containers with open or closed ends. The side walls were assumed to be at the same depth. Hunter (1985) proposed equations for calculating the volume of various conical piles. The information required to calculate the volume of grain in a rectangular flat storage is width and length of the storage, depth of grain at walls, and either maximum grain depth or angle of repose. The angle of repose determines the slope of the grain from a wall to the peak and is a key factor in determining grain volume, but it is seldom measured in a storage. Angle of repose depends on grain type, moisture content, amount of fines and foreign material and height of // FP—7 V2 V3 V1 storage width, m (It) storage length, m (it) grain depth at side walls, In (it) level fill volume, m3 (ft3) triangular peak volume, m3 (113) and peak volume, m3 (ft3) . Typical flat grain storage divided into areas for volume calculation. fl- drop I and II Table angle: (hep Corn Badey Sunfl0I Oats Durum Spnng Overall I-\' Mlde desired "II ukat 13 drop (MWPS, 1987). Midwest Plan Service (1987) published average, minimum and maximum filling angles for common grains (Table 1). Table 1. Average, minimum and maximum angles of repose for some grains-1 Angle of Repose (deg) Crop 319L399. minimum 113331811101 Corn 25 22 28 Barley 28 24 34 Sunflower 28 20 40 Cats 28 24 32 Durum wheat 23 22 25 Spring wheat 25 19 38 Overall 27 18 40 1Midwest Plan Service (1987). Brooker et al. (1974) listed the angle of repose for barley at 30 degrees; rice at 36 degrees; shelled corn at 27 degrees; soybeans at 30 degrees; and wheat at 31 degrees. Pierce and Bodman (1987) conducted a field study to determine the piling angles for shelled corn and milo in flat grain storages. They found the average angle of repose for shelled corn and milo to be 23 and 29 degrees, respectively. These angles are approximately 4 degrees lower than repose angles appearing in current references. DUCT PLACEMENT Duct placement in flat storages is governed by the grain profile and the desired minimum air path ratio. Air path ratio is the ratio of the longest distance air travels through the grain compared to the shortest distance (Figure 2). As A- 8.. C2 AI! pa Figure 2. ma"Imun 14 -—-—-—-—> D -——--—--—_-_--—-+ —> ('J 21> I I I I 0 w I i 0 up I i I L A - air path from duct to grain surface along outside wall B - shortest distance or air path from duct to grain surface C - air path from duct to center grain surface Air paths A and C are less than or equal to 1.5 ' B Figure 2. Cross section of grain storage with duct placement to achieve maximum air path ratio of 1.5. l-I . discusse dimensic Vanator member The I through Circuit t I”Dona Storage Carefull increas The determ 01 the I desert lnStaIIe filled 0 Level. In II deep (( diStanc ”‘9 erai Storage. Thes ducts m, 15 discussed in the previous section, the grain profile is determined by building dimensions, grain depth at walls, peak grain depth and angle of repose. Variations in duct spacing may be required to accommodate doorways, framing members and equipment limitations. The principle for duct placement in flat storages is to maintain air paths through the grain as equal as possible, with no place where the air can 'short circuit' to the edge of the storage. The layout of a duct system becomes more important in flat storages, due to varying grain depths, compared to upright storages (Foster and Tuite, 1986). Holman (1960) noted that ducts must be carefully spaced since the amount of poorly aerated grain increases with an increase in distance between ducts. The design procedure for placement of ducts in flat storages includes determining the location of ducts in the storage cross-section and the end points of the perforated ducts. Locating ducts in the storage cross-section (as described in the following sections), depends on whether the ducts are to be installed lengthwise or crosswise to the storage and whether the storage is level filled or peaked. Level Filled Storages In level filled storages, ducts should be placed as far apart as the grain is deep (Cloud and Morey, 1980; Foster and Tuite, 1986; Holman, 1960). The distance from the storage wall to the nearest duct should not exceed one-half the grain depth (Foster and Tuite, 1986). This design guideline for level filled storages results in an air path ratio of 1.5:1. These guidelines for level filled storages apply regardless of whether the ducts run lengthwise or crosswise. Generally, running ducts lengthwise reduces the number of ducts and fans required for an aeration system. Duct systems and [909 16 designed for level loaded storages are seldom adequate for peak loaded storages. Peak Loaded Storages General guidelines for peak loaded flat storages with lengthwise ducts dictate that the air path ratio should not exceed 1.5:1 (Cloud and Morey, 1980; Foster and Tuite, 1986; Holman, 1960; MWPS, 1987) and the distance between ducts should not exceed the average grain depth (Brook and Harmsen, 1982; MWPS, 1987; Peterson, 1985). Burrell (1974) reported that air path ratios of 1.821 were satisfactory and that ratios as high as 2.7:1 had been reported to achieve adequate cooling in shallow level loaded stores in the United Kingdom. Burrell (1974) considered a ratio of 2:1 adequate for small stores where grain depth on side walls is 1.5 m (5 ft) or less. Besides the general guidelines, Holman (1960) reported that performance has been satisfactory with one lengthwise duct in storages up to 12.2 m (40 ft) wide and grain 3.7 to 4.6 m (12 to 15 it) deep. Recommendations for storages less than 12.2 m (40 ft) wide are one lengthwise duct in the center of the storage (Cloud and Morey, 1980; Foster and Tuite, 1986; MWPS, 1987; Peterson, 1985). These guidelines, which conflict with the previously stated general guidelines of maintaining an air path ratio of 1.521, were adopted to economize equipment costs in aeration systems. The maximum length of duct allowable from a fan is a limitation in aeration system design. Recommendations range from 22.9 m (75 ft) (Holman, 1960) to 24.4 m (80 ft) (Cloud and Morey, 1980; MWPS, 1987) to 30.5 m (100 ft) (Foster and Tuite, 1986). For plastic ducts Brook (1983) recommended a maximum length of 18.3 m (60 ft). 17 WIdthwise ducts in peaked grain storages generally should not be spaced wider than the least depth of grain (Holman, 1960). Holman (1960) suggested that when a large difference exists between the grain depth at the wall and at the peak, some deviation from this recommendation may be warranted to hold the cost of the duct system to a practical limit. Too much deviation, however, can result in considerable additional hours of fan operation to completely aerate the grain receiving the lowest airflow. Cloud and Morey (1980), Foster and Tuite (1986), Holman (1960) and MWPS (1987) recommended that widthwise ducts spacing be equal to average grain depth. Specific recommendations for duct placement in flat storages by Cloud and Morey (1980), Foster and Tuite (1986), Holman (1960) and Midwest Plan Service (1987) are depicted in Figure 3. These recommendations are somewhat vague. Although ranges of storage width and length dimensions are given,no range of suitable grain depths on walls or at the peak are given. Storage profiles with shallow grain depths at walls will result in air path ratios exceeding 2:1. Duct End Points In flat storages, the perforated aeration duct usually does not start at the end of the storage, but is offset into the grain profile. Air paths through grain should be as equal as possible with no place where the air can 'short circuit' to the storage surface (Foster and Tuite, 1986). Burrell (1974) recommended the distance of the perforated duct from the end of the storage plus the grain depth at the and be equal to the longest air path elsewhere in the storage. Peterson (1985) suggested that the perforated duct should generally be the same distance from the end of the storage as the first duct is from the side of the storage. r—< 18 T—-<—1 {I Recommended width (W) and length (L) of storages is as follows: In A: In B: In C: In D: In E: Figure 3. Aeration duct arrangements for flat storages recommended by Cloud and Morey (1980), Foster and Tuite (1986), Holman (1960) and Midwest Plan W - up t012.2 rn (40 ft) L - up to 24.4 In (80 it) 30.5 In (100 ft) W . upto12.2 In (40 it) L - up to 53.3 m (175 it) W .12.2to18.3 m (40 to 60 ft) L - 24.4 m (80 ft) (Cloud and Morey, 1980; Foster and Tuite, 1986; MWPS, 1987) (Cloud and Morey, 1980; MWPS, 1987) (Foster and Tuite, 1986) (Cloud and Morey, 1980; MWPS, 1987) (Cloud and Morey, 1980; MWPS, 1987) (Cloud and Morey, 1980; MWPS, 1987) (Cloud and Morey, 1980; MWPS, 1987) W - 21.3 to 30.5 m (70 to 10011) (Holman, 1960) up to 36.6 m (120 ft) L - up to 53.3 m (175 ft) W - up to 24.4 In (80 it) up to 30.5 m (100 It) L - up to 24.4 m (80 it) up to 30.5 m (100 it) Service (1987). (Foster and Tuite, 1986) (Foster and Tuite, 1986; Holman, 1960) (Cloud and Morey, 1980; MWPS, 1987) (Foster and Tuite, 1986) (Cloud and Morey, 1980; MWPS, 1987) (Foster and Tuite, 1986) XI 19 FAN SIZING Fan sizing is based on the volume of air required for a duct and the static pressure. Static pressure in an aeration system is a measure of the power required from a fan to force air against frictional resistance caused by ducts and grain and is usually measured in kPa (in. H20) (Brook, 1979). Static pressure increases with increasing grain depths and increasing airflow rates and varies with grain type, concentration of fines and bin filling method (MWPS 1987). Airflow delivered by a fan decreases as static pressure increases. Airflow required for each duct is calculated by multiplying the volume of grain aerated by the duct times the desired airflow per unit. For example, if the volume aerated by a duct equals 176 m3 (5,000 bu) and the desired airflow rate is 0.08 m3/min/m3 (0.1 ft3/min/bu), then the airflow required is 14.2 m3/min (500 ft3/min). Static pressure is estimated on the basis of grain type and grain depth. The airflow resistance equation in the American Society of Agricultural Engineers standard 0272.1 (ASAE, 1987) is: AP a 02 m“ = (1) L loge (1+bO) where: AP - pressure, Pa (in. H20) L . bed depth, m (It) a - constant for particular grain O - airflow rate, m3/s-m2 (ft3/min/ft2) b . constant for particular grain The constants a and b used in the airflow equation for selected grains are listed in Table 2. 20 Table 2. Values for constants a and 0 used in airflow resistance equation.‘ Value of a Value of b Value of a Value of b Grain Pa 82m3 mzs/m3 in. H20 min2/ft3 ft2/ft3/min Shelled corn 2.07 x 104 30.4 6.54 x 10'4 15.44 x 10'2 Soybeans 1.02 x 104 16.0 3.22 x 10'4 8.13 x 10'2 Wheat 2.70 x 104 8.77 8.53 x 10'4 4.46 x 10'2 Sorghum 2.12 x 104 8.06 6.70 x 10-4 4.09 x 10-2 1American Society of Agricultural Engineers data: D2721 (ASAE, 1987). This equation is suitable for estimating static pressure through clean, dry, loose-fill grain. In practice, static pressures are further increased to compensate for pressure losses in ducts, fines, and packing (Brook, 1979; Foster and Tuite, 1986; Holman, 1960). Holman (1960) compensated for packed fill by increasing static pressures by 30 percent for corn and wheat; 40 percent for grain sorghum, rice and soybeans; and 50 percent for cats. Holman (1960) increased static pressures by another 20 percent to compensate for pressure loss through supply pipes, ducts and surrounding grain. Typically, static pressure for clean, loose grain is calculated and then increased by a factor specific to each grain. Midwest Plan Service (1987) listed the following factors for adjusting static pressure determined by the airflow resistance equation (1) to reflect field conditions: 1.5 for shelled corn, 1.3 for soybeans, 1.3 for wheat and 1 .5 for grain sorghum. Once the required airflow and estimated static pressure are known, the power requirement of a fan can be calculated in traditional units as follows, assuming an installed static efficiency of 47 percent (Foster and Tuite, 1986; Holman, 1960): 21 Fan HP - airflow, ft3/min ' static pressure, in. H20 I 3,000 (2) Manufacturers' fan specification charts should be consulted to select a fan. Required airflow at a static pressure must be known and the estimated fan horsepower can be used as a starting point. Brook and Harmsen (1982) used manufacturer‘s fan performance charts to generate 'A' and 'B' values for fans. These values were used in a computer program to estimate fan airflow (in traditional units) given a static pressure. The equation is: Airflow, Ila/min :- A - B " (static pressure, in. H20)2 (3) DUCT SIZING After the actual airflow to be delivered to a duct is known, the duct can be sized. The important dimensions of a duct are (1) the cross-sectional area, which influences air velocity within a duct and (2) perforated surface area, which affects velocity of air exiting a duct (Cloud and Morey, 1980; Holman, 1960). Diameter Duct diameter is determined by required duct cross-sectional area. Midwest Plan Service (1987) stated that a duct cross-sectional area should be large enough to insure that static pressure and air velocity are not excessive. High air velocities increase fan power requirements and can cause non-uniform airflow from the duct (MWPS, 1987). Duct diameter is therefore based on allowable air velocity within the duct. Maximum recommended air velocities in ducts for flat storages with suction systems, as given by Holman (1960) (in traditional units), are listed in Table 3. lhi CO De 22 Table 3. Recommended maximum allowable air velocities within ducts installed in flat storages with suction system aeration.‘ Air velocity within ducts (ft/min) for various grain depths corn, soybeans, large grains wheat, grain sorghum, small grains ft3/min lbu 10ft 201i 30ft 40ft 50ft 10ft 201t 30ft 40ft 50ft 1/20 --- 750 1 000 1 250 1 250 --- 1 000 1 500 1 750 2000 1/1 0 750 1 000 1 250 1 500 1 750 750 1 500 2000 ---- --- 1/5 1 000 1 250 ---- --- --- 1 000 2000 ---- --- ---- lCalculated for suction systems with ducts up to 100 ft in length. Assumes duct with rough inner surface and corrugations or inside framing. Duct friction loss calculated using a roughness coefficient of 2.5; velocity head loss equal to 1.7 hv (Shove, 1959). Grain type, depths and airflow rates were considered in the development of this table. mm long ducts in flat storages it is beneficial to make the fan connection near the mid-point of the duct (Holman, 1960). This permits a 50 percent reduction in the cross-sectional area of a duct. Other sources recommended one value or a range of values for the maximum airflow. The recommendations are summarized in Table 4. 23 Table 4. Recommendations for maximum airflow velocity in ducts. Velocity Source Restrictions m/min (ft/min) 457 (1500) Brook 1979; MWPS 1987 457 (1500) Cloud and Morey 1980 open flow areas 610 (2000) Cloud and Morey 1980 lengths up to 9 m (30 ft) in bins deeper than 4.3 m (14 ft) 305-457 (1000-1500) Noyes 1967 lengths 7.6-18.3 m (25-60 ft) 457-610 (1500-2000) Noyes 1967 lengths up to 7.6 m (25 ft) 457-610 (1500-2000) McKenzie 1978 Midwest Plan Service (1987) listed the maximum design velocity for plastic ducts at 457 m/min (1500 ft/min). The equation commonly used for determining the required cross sectional area of a duct is (Brook, 1979; Cloud and Morey, 1980; Holman, 1960; McKenzie, 1978; MWPS, 1986; Noyes, 1967): cross-sectional area, rn2 (it?) - airflow, m3/min (lt3/min) / design air velocity, anin (It/min) (4) Length Minimum duct length is determined by the required duct surface area. There must be enough perforated area to insure that air leaving the duct is not constricted nor the velocity too high. The effective surface area of a round duct Is reduced by 20 percent due to contact with the floor (Foster and Tuite, 1986; Holman, 1960). Required duct surface area is determined based on the maximum airflow velocity at the duct surface. Various recommendations for airflow velocity at the duct surface are summarized in Table 5. 24 Table 5. Recommendations for maximum airflow velocity at duct surface. Velocity Source m/min (ft/min) 6.1 (20) Holman 1960 7.6 (25) Cloud and Morey 1980 9.1 (30) Brook 1979; Foster and Tuite 1986; MWPS 1987 7.6-9.1 (25-30) McKenzie 1978; Noyes 1979 Duct surface area requirement is commonly calculated as follows (Brook, 1979; Cloud and Morey, 1980; Holman, 1960; McKenzie, 1978; Noyes, 1967): duct surface area, m2 (It?) - airflow, m3/min (ft3/min) / duct surface velocity, anin (ft/min) (5) SUPPLY TUBE SIZING Supply tubes are ducts without perforations. Supply tubes are required to connect fans to perforated ducts. The factor for sizing supply tubes is the maximum allowable airflow velocity in ducts. Foster and Tuite (1986) suggested a design airflow of 457 to 762 m/min (1500 to 2500 ft/min), with velocities above 610 m/min (2000 ft/min) for deep bins or short duct lengths. Holman (1960) also limited airflow velocity to 762 m/min (2500 ft/min) with a recommended range of 457 to 610 m/min (1500 to 2000 ft/min). Equation 4 is used to determine the minimum cross sectional area of a supply tube. EXHAUST AREA SIZING An air exchange opening must be provided in the storage structure for intake (suction systems) or exhaust (pressure systems) air. Midwest Plan Service (1987) recommended at least 0.09 m2 (1 ft?) of opening in the roof or eaves for 25 each 28.3 m3/min (1,000 ft3/min) of airflow. This allows air to exit at a velocity of 305 m/min (1,000 ft/min). The previously discussed recommendations are required to design an aeration system. The aeration system design program described in Chapter IV incorporates these guidelines into the placement and sizing calculations. CHAPTER III DEVELOPMENT SYSTEM FOR AGRICULTURAL DESIGN PROGRAMS Computer graphics technology has provided tools for computer programs to display information in graphic form. This technology is currently available on microcomputers and can be utilized for development of computer programs. Advantages of graphic display for agricultural engineering design applications are two-fold. FIrst, illustrations can expedite information conveyance when a new concept is being described to a user or a choice involving unfamiliar terminology is requested. Second, design drawings can be presented. This chapter presents a development system for agricultural engineering application programs. Discussion of the system includes components of the problem-solving process for agricultural engineering design problems and the software tools used to implement each component. Concepts for this development system were previously presented (Watson et al., 1986). COMPONENTS OF DEVELOPMENT SYSTEM A system for developing agricultural engineering design programs should represent the problem-solving process used in design problems. The solution to design problems is a design drawing with specifications and related recommendations. Some aspects of the design drawing are predetermined, while others must be obtained by querying the client or through calculations. 26 27 The interactive process with a client begins by asking questions. When sufficient information has been acquired, calculations are performed, a design drawing with specifications is rendered and recommendations are made. The design expert controls the progression of these steps and may reiterate them to test alternatives. A computer program to simulate the role of an expert in an interactive session with a client should include five basic components. These components, and their purposes are -- Interview -- questions the client to obtain information about the design problem and educates client as needed. -- calculations -- utilizes problem information obtained from the interview session to determine appropriate size and component characteristics for the design drawing. -- design drawing - utilizes size and component calculations to generate a customized plan with specifications to meet the client's needs. -- management recommendations -- prescribes appropriate recommendations for successful implementation and usage of customized design. - framework - controls operation of the interview, calculations, design drawing and management recommendations components. INTERVIEW An interactive computer application, by definition, requires input from a client. Clients are prompted with a question and requested to respond with an appropriate answer. This process is referred to as the interview. The purposes of the interview process are 28 -- to display questions and educational information to a client. -- to control the order of questions and educational information presented to a client. -- to receive client responses and check for reasonable values. Computer graphics are an important part of the interview process just as visual aids are important tools of an expert when working with a client. A computer directed interview session can incorporate graphics by displaying - drawings and illustrations developed with graphics software. -- video tape and video disc stills and sequences. -- images captured from a video camera or video tape. One or more of these methods are suitable for design programs. Many questions asked of a client benefit from graphic representation. An example from a dairy free-stall barn design application illustrates this point (Figure 4). A client has the option of choosing among wood, suspended, and MSU suspended free stall partitions. Drawings minimize the amount of text needed to communicate clearly with a client. CALCULATIONS Engineering problems often require calculations to reach a solution. The goal of the calculations component is to complete all calculations necessary for a design problem. The purposes of the calculations component are -- to read client responses and reference data from a data file. -- to perform all calculations necessary to complete the design process. -- to store the calculated results in a data file for use by the other components of the development system. The calculations component comprises calculations for all possible entities of a design. Some calculations may be used several times when the finished plan consists of several of the same entities. For example, an aeration system plan 29 Free Stall Dividers wood Select a Free stall partition types wood suspended MSU suspended suspended f —— MSU suspended Press .I-‘or- help with question. Pres-SEE] For help with connonds. Figure 4. Sample question from interview component, illustrating the necessity of graphics to communicate effectively with a client. (Ira aCC adl 30 may consist of 1, 3, or 9 ducts. The same duct sizing calculations are performed to size each duct. The calculations component may be a program that is separate from the other components. The calculation program must adhere to the data exchange procedure defined by the framework component. The developer can define any practical data organization within the calculations program as long as the program can read and write a data file in the format specified by the framework component. For example, as part of an aeration system design program, the peak grain depth is calculated. After the interview component acquires storage dimensions, grain depth at side walls and angle of repose information, a data file is written containing the client responses and the framework executes the calculations program. The calculations component executes three functions. First, client responses from the interview session are read from the data file. Second, the calculations are performed. Third, the resulting value for peak grain depth is written in an output data file for use by the other components. When the calculations component terminates, the framework component reads the calculations output data file and passes the value for peak grain depth data to the interview component for display. DESIGN DRAWING Once the calculations to size components have been completed, a drawing of the customized design is generated for the client. The role of the design drawing component is to generate a unique plan based on client-specified and calculated values. The application developer must be able prepare a generic design drawing that can be customized to meet a wide range of client needs. This is accomplished with a parametric computer aided drafting processor which allows a developer to 31 -- use variable quantities to define lines, circles and arcs which are the primitives of a drawing. -- use the elements to draw any entities which may be needed to produce a unique plan. -- determine which components are needed in a specific plan. -- assign client-specified and calculated values to variable quantities of the primitives of each entity. -- place the entity drawings in the plan. -- provide a paper copy of the final plan. _ During application development. the design entities are drawn with variables representing dimensions that the developer may need to change for a custom design. During execution of the application program, the design drawing component uses available data to assign values to the custom drawing and displays the drawing. Design problems typically consist of common elements, even though many possible variations exist. For example, design of an aeration system involves ducts. Diameters and lengths of ducts vary with the required grain storage profile. A parametric duct drawing for a plan view could simply be a rectangle. The width and length of the rectangle are assigned variable names. During execution of the application, the required duct diameter and length are calculated. The design drawing component reads the diameter and length values, assigns the values to the variables, and displays the plan view of the duct with dimensions. Although, this is a simple example, complex drawing can be broken into entities and blocks in a similar manner to generate custom drawings (Figure 5). 32 100' 50' _, 7:7 “l :04)— l 2? an; _ nuct4_ 8 9'-6'l It A i Duct 3l ear-3' _J a so A Duct 2 I i l l as'-3' _| .m *1 3'” il— . Duct 1 (U :l0 9"61 IL_°_‘IL_ ___I HP |_ 50' fl. Figure 5. Sample customized plan view drawing of an aeration system, representing a design drawing to be provided to a client. 33 MANAGEMENT RECOMMENDATIONS An expert's work is not complete once a customized drawing is prepared, but also includes providing the client with a set of management recommendations relative to the design. In fact, effective communication of management recommendations is often critical to successful implementation and usage of a new design. Management recommendations are often dependent upon specific options employed in a customized design. The roles of the management recommendations processor are -- to process management recommendation rules to determine which recommendations are relevant to client responses and design decisions. -- to prepare paper copy of the management recommendations. For example, a client might request assistance with an aeration system for an existing building. The aeration system expert recommends placing a vapor barrier on the floor of existing buildings and under the concrete for new buildings. The appropriate recommendation should be printed for the client (in this case, putting a vapor barrier on the floor). Questions such as "How often should I run the fans?" and, ”How do I know the grain is cool enough?" should be either in the recommendations list or a reference should be provided to an appropriate source. In a thoroughly developed application, many of the management recommendations may already be incorporated into the educational material of the interview. The recommendations should still be prepared in printed form for the client to take home. This is a crucial point for computer based applications and can prevent problems during implementation and usage of the design. When a question arises. a client can refer to his files for the pertinent recommendation instead of relying on his judgment until an expert is available for consultation. 34 The amount and content of management recommendations should be tailored to the general needs of the client group. Generally, the least common denominator of client knowledge should be the guiding factor. FRAMEWORK The fifth component is needed to supervise interaction with a client. A client should not interact with each of the other four components independently. The supervising component is referred to as the framework. The roles of the framework are -- to tiethe independent components together into a cohesive application, from a client's perspective. -- to manage data exchange among the components. -- to provide supplemental flow control during the interview. - to activate the calculations component. - to supervise operation of the design drawing process. -- to activate the management recommendations component. -- to facilitate client 'what-if' scenarios. For example, a simple application to determine the profile of a grain storage requires a framework to activate the components. First, the interview is initiated to request length, width and depth values. Second, the calculations process is performed to calculate the grain depth at pertinent points. Third, the design drawing processor is called to display a grain profile drawing with dimensions. Fourth, the management recommendations process is initiated to search for and print pertinent recommendations. Once these processes are complete, the framework offers the client an opportunity to change values and reinitiate the same processing sequence. 35 Each software product which comprises a component is used for application development. A client interacts with an application via the framework and execution of other software products is transparent (Figure 6). The selected method of implementing the framework component was to make it an integral part of the interview component. By definition, the framework controls the interaction of the client with the other components. Since the interview component requires the most interaction, integrating the interview and framework components was a logical step. The framework consists of additional . capabilities added to the interview processor and a set of guidelines for data exchange among the components. SOFTWARE TOOLS FOR DEVELOPMENT SYSTEM Various software tools are currently available to implement each component of the development system. In this section the types of software tools available to implement each component and the tools used in the aeration system design program are discussed. The set of software tools synthesized for developing the aeration system design application included commercial software and software developed in the Interactive Computer Graphics Laboratory of the Agricultural Engineering Department at Michigan State University. Documentation of the commercial software is available from the manufacturers. The Interactive Computer Graphics Laboratory maintains documentation of software developed in that facility and instructions for developing other engineering design applications with the same set of software tools. New versions of software tools are being developed which will better facilitate the use of computer graphics. These new tools will serve to simplify a program 36 Figure 6. Conceptual relationship of program developer and client with the development system software components. ”\f'l FRAMEWORK (x g -—| INTERVIEW I“ E —.| CALCULATIONS |~ If: g —-l DESIGN DRAWING I” H g ' R —.| RECOMMENDATIONS I" K/fl FRAMEWORK v 37 development process. Due to the modular design of the software system, new software tools can be utilized without redoing an entire application. INTERVIEW The interview session should be tailored to a client group. Generally, as the experience level of the client group increases, fewer graphics are needed to supplement information transfer during an interview. Many commercial software products are available for implementation of an interview session. Computer-aided instruction or authoring programs fulfill the basic roles of the interview component and facilitate display of graphical images and control of video tape or disc. Incorporation of captured video images and high-resolution painted images requires specialized software routines. Manufacturers of image capture adapters for microcomputers typically provide software tools for their products. These software routines can be used to display video images which are stored on magnetic media. Other products allow a developer to design interview screens and generate source code in one or more common computer languages. This source code can be incorporated into a program. A computer program referred to as the interview processor was written in the 'C' programming languages to meet the requirements of the interview component. Existing computer aided instruction programs did not provide capabilities of simultaneously displaying video quality images and text. The interview processor provides a standard user interface for all applications developed with it and greatly reduces the amount of computer programming by an application developer. The organization of information on the display screen is controlled by the interview processor, and the developer determines the text and graphical images to be displayed. 38 The interview component of the aeration system design application was implemented by preparing an ASCII (American Standard Code for Information Interchange) file which defined each item to be displayed on the screen, including the title, question, prompts, text, names by which to reference responses, default values, range limits of responses, graphic images and the next screen for display. Two '0' functions were written to provide additional features needed by the framework (see Appendices B and C). One function performed consistency checks to verify that a response was consistent with previous responses. The second function provided capabilities of running external programs before exiting a screen. This latter function was used to execute the calculations, design drawings, and management recommendations components. CALCULATIONS The calculations component could be a stand-alone program that reads and writes input and output data via data files. In most cases, the calculations component must be coded by the developer. Any programming language which can produce an executable file can be used, allowing the developer to work with a familiar language. The calculations for the aeration system design application were coded in the 'C' programming languages. The code was compiled with a commercial 'C' compiler for microcomputers. The calculation module was linked with the interview processor to produce one program. The details of the calculations algorithms and procedures are in Chapter IV. DESIGN DRAWING Parametric computer-aided drafting (CAD) programs have existed on mainframes and specialized computer systems for several years. At this time, very few products exist to do this type of work on microcomputers. AutoCAD, a 39 commercial (CAD) program, and Synthesis, a commercial parametric CAD extension for AutoCAD, when used together, bring many features of parametric CAD to microcomputers (Figure 7). Following the aeration system example, the program developer uses AutoCAD to draw aeration system components (called master drawing files in Figure 7). Variable dimensions are added and assigned variable names. During initial processing of the design drawing component, a specification file must be written or updated. (A developer-written program must perform this task.) The specification file contains drawing file names of entities and values assigned to variables. Synthesis is invoked and processes the specification file to define the customized drawing. The customized drawing is routed to AutoCAD for display and paper copy. Carroll, Peterson and Watson (1987) described the procedure for using AutoCAD and Synthesis in an aeration system design application. Detailed documentation of the features and usage of AutoCAD and Synthesis may be found in the respective user's manuals. Development of the design drawing component of the aeration system design program consisted of drawing the master drawing files for each component and writing a program which creates a specification file for Synthesis to use in preparing the custom drawing. The master component drawings were drawn with AutoCAD using the Synthesis command set. The program which writes the specification file for Synthesis takes into account each possible arrangement of the components. MANAGEMENT RECOMMENDATIONS Searching for and printing management recommendations can be accomplished with a data base query routine or an expert system. A data base 4O HASTER DRAWING FILES SPECIFICATION FILE (Created by AutoCAD) (Created by Design program) Housmsp wmoowpxr Roomxr WALLDXF This file SDGCIHBS: ”which drawing me( 3) to two used ' computed dimensions ' annotation: of drawing " scaling factor: ' insertion point: 't rotation of towing“) A SYNTHJEX: fo/J Create a final trawlng ' Plotted Drawing " Based upon the Instructions contained In ‘ spaciflcatlm flla. , ' customize: the Images of tha specified ' master drawings " marw them Into wlput d'uwlnq / ‘( Housapxr AUTOCAD Merged drawing file (Drawing Processor) _-" of a house Plot merged drawing Figure 7. Functional description of Synthesis and AutoCAD usage to produce a parameterized design drawing. Copied with permission. (c) 1985, TransformerCAD. Bellingham, WA. 41 of management recommendation files can be established corresponding to available client responses. A data base query routine would search the data base for recommendations which match client responses and prepare a paper copy. An expert system of possible management recommendations can be developed and initiated by supplying the list of client responses. The management recommendations component was implemented with a relatively simple data base technique. An application developer must prepare a file of all possible management recommendations. The file may be written with any commercial product that will write an ASCII file. The file must contain a specified set of character sequences to identify the separate recommendations. A program was written to process the file of management recommendation text into a ‘keyed' data file of specific format. Information at the beginning of the file relates each management recommendation to a file location for random access file processing. The keyed data file is used by a program called the recommendations processor. The recommendations processor is written in the 'C' programming language. For the aeration system design application a '0' function was written to use data from the interview processor and calculations component to determine which recommendations to print. The recommendations processor inserts actual values in the place of variable names when printing the recommendations. FRAMEWORK The framework's primary function is to provide logical flow control for an application. Various levels of programming tools can be used to accomplish this task. In some cases, a batch command file may be sufficient. Any programming language which allows execution of external programs with control returning to the original program will work. Expert system development tools which can 42 activate external programs to provide information or accomplish goals are another alternative. The framework was implemented as an integral part of the interview component. The interview processor was enhanced to allow execution of external programs. Data is transferred to and retrieved from an external program by a data file. The format of the data file is documented by the Interactive Computer Graphics Laboratory and any external program may access the data by interpreting the file correctly. The implementation of the framework allows program users to try one set of input data and then to change one or more data items to determine the effect upon the design. CHAPTER IV AERATION SYSTEM DESIGN PROGRAM An aeration system design application was developed using the development system described in Chapter III. Aeration system design is a good example of an agricultural engineering problem that is encountered by field staff of the extension service but is usually referred to the state specialist. The process of designing an aeration system can take several hours as similar calculations may be performed many times before a suitable design is achieved. The aeration system design program described in this chapter eliminates the need for time- consuming calculations for most fann-sized grain storages. The aeration system design program is intended for use by aeration system experts in designing systems for farm-sized grain storages. The description of the aeration system design program is divided into the four components of interview, calculations, design drawing and management recommendations. INTERVIEW The interview component of the aeration system design program consists of 15 main screens which request information about the design problem. These screens with their titles and descriptions are listed in Table 6. Besides information required to size and place aeration equipment, information about the sthcture is requested to verify post size requirements for the user's storage 43 44 structure. Appendix A is a listing of the interview text file which the interview processor uses to display the screens. Table 6. Response screens for aeration system design program. # Screen Title Description 8 9 client information grain type new structure construction type post-spacing structure liner storage size grain depth on walls maximum piling height 10 number of ducts 11 duct type 12 duct direction 13 fan type 14 fan arrangement 15 airflow rate name and address information for contacting person for whom the design is prepared grain to be stored: shelled corn, soybeans, wheat or grain sorghum new structure for storage (yes or no) used for making recommendations post-frame construction (yes or no), if yes post size is calculated ‘ If post-frame construction, used to calculate post suze asks if information needed on grain liners, if yes, a source of plans is provided length and width of storage grain depth may be entered for each of 4 walls limiting height for piling grain used to calculate peak grain depth may be computer selected or user selected duct type used: plastic aeration, spiral-Iok metal, round metal or half-round metal lengthwise or widthwise duct placement axial or centrifugal tans fan placement options; end, middle or combination of end and middle of duct aeration airflow rate The screens are presented to the user in the same order as they appear in Table 6 except as described below. If the response to screen four is a non-post frame building then screen five is not displayed. If the response to screen four is a post frame building then a screen is displayed after screen eight which gives 45 the minimum post size for the storage structure. After screen nine, a screen is displayed which lists the capacity and peak height of the grain in the storage. If the response to screen ten is 'user selected' number of ducts then an additional screen is displayed which asks how many ducts to use. After screen fifteen, the main calculations are performed and a screen is displayed listing the number of ducts used in the design or describing an error condition that prevented completion of a satisfactory design. If the calculations were successful the next screen displays the design drawing. The design drawing is printed and the following screen asks if the user is ready for the management recommendations. It the user responds affirmatively, the management recommendations are printed and the final screen gives instructions about quitting the program or changing responses. The user can terminate the program or return to previous screens to change responses and generate a different design. A graphic illustration is displayed with each response screen. The graphics are based on line drawing and digitized slides. The illustrations were prepared using a commercial software program called 'ICBTIPS' (AT&T, 1985) which was obtained from AT&T for use with their image capture video board. Each illustration was developed to convey additional information about the response screen with which it was displayed. As discussed in Chapter III, two functions were written to provide the additional features needed by the framework. These functions are specific to the aeration system design application. One function is used to to verify that a user's response is consistent with previous responses (see Appendix B for source code). Consistency checks are initiated when the user completes a screen. If an inconsistency occurs, a message is displayed to the user and the user is prevented from moving forward until the inconsistency is corrected. 46 Table 7 describes the consistency checks for the aeration system design program. Table 7. Consistency checks for aeration system design program. # Screen Title Consistency Check 7 storage size storage width must not be greater than storage length 8 grain depth on walls grain depth at the lower side (end) wall must not be greaterthan the higher side (end) wall 9 maximum piling height grain depth at the higher side or end wall must not be greaterthan maximum piling height The second function was written to provide supplemental flow control for the application. This function is used if the next screen to be displayed can vary or if a special procedure (such as calculations) is needed (see Appendix C for source code). Table 8 describes the use of this function. 47 Table 8. Supplemental flow control for aeration system design program. # Screen Title Description of supplemental flow control 8 grain depth on walls 9 maximum piling height 10 number of ducts 15 airflow rate if not post-frame construction display screen 9. If post-frame construction run post sizing calculation and display screen listing post size or warning if the largest post size is not suitable. run storage capacity calculation and display results or message that storage is too small for program to design an aeration system. if 'computer selected' is the response set desired number of ducts to zero an component placement and sizing calculations and display number of ducts used or error message run design drawing processor run management recommendations processor CALCULATIONS The calculations component of the aeration system design program contains all of the calculations necessary to specify a customized aeration system for a grain storage. Results of the calculations module are used in the design drawing processor to define dimensions of the parametric drawing and in the recommendations module to describe the storage and aeration equipment. The calculations module begins processing with the assumption that all necessary information about the client's grain storage is available and valid. All checks for valid responses must be performed before the calculations module is executed. 48 The aeration system design procedure described by Holman (1960) is employed. For program development and description, the calculations module was divided into the following seven procedures: post sizing storage capacity duct placement duct length fan placement and size duct size connector placement and size POST SIZING Post size does not affect the design of an aeration system, but is calculated to assist the program user in determining the allowable grain depth on the side walls of the storage structure. Post size is determined based on post spacing and the highest grain depth on a wall. Post size, spacing and allowable grain depth data from Irish et al. (1984) is used to find the minimum post size (Table 9). Table 9. Allowable grain depth for post size and post spacing‘. Post Spacing on Centers Post Size 0.6 m (2 ft) 1.2 m (4 ft) 1.8 m (6 ft) 2.4 (8 ft) cm (in.) 20 x 20 (8 x 8) - -------- 3.2 m (10.6 ft) 2.8 m (9.2 ft) 2.6 m (8.4 ft) 15 x 20 (6 x 8) 3.7 m (12 ft) 2.9 m (9.5 ft) 2.5 m (8.3 ft) 2.3 m (7.5 ft) 15 x 15 (6 x 6) 3.0 m (9.7 ft) 2.3 m (7.7 ft) 2.1 m (6.8 ft) 1.9 m (6.1 ft) 10 x 15 (4 x 6) 2.6 m (8.4 11) 2.0 m (6.6 ft) 1.8 m (5.8 ft) 1.6 m (5.3 ft) 10x 10 (4x4) 2.2 m (7.1 11) 1.7m (5.6 ft) 1.5m (4.9 ft) 1.4m (4.5 ft) 1Post sizes listed are nominal. Allowable grain depth from posts of actual dimensions (e.g. allowable grain depth for 6 x 6 post from 5.5 x 5.5 post size listed by Irish et al.). 49 STORAGE CAPACITY The first step in the aeration system design process is to determine the grain capacity of the storage. This procedure is executed during the interview component and the capacity is displayed to the user. If needed, the user can alter building dimensions and grain depths to arrive at the desired capacity. The storage capacity procedure performs the following calculations: 1) peak grain depth of storage 2) width and length of the peak grain depth 3) grain capacity of the storage The peak grain depth calculation uses the storage dimensions and grain depth to calculate the maximum possible peak depth obtainable both widthwise and lengthwise in the storage. The potential peak grain depth widthwise in the storage is determined with the following equation: 0M - on + (6) 2 . where: Dpeak - peak grain depth, m (It) 0,. - grain depth at higher side wall, m (it) D). - grain depth at lower side wall, m (It) W - storage width, m (It) 0 - angle of repose of grain, deg The calculation for lengthwise peak grain depth exchanges side wall depths for end wall depths and storage width for storage length. The potential peak grain depths widthwise and lengthwise in the storage are compared to maximum piling height information provided by the client and the smallest of the three values is the peak grain depth of the storage. The width and length of the peak grain depth is calculated for use in the storage volume and duct spacing calculations of the design process. The width of the peak grain depth is calculated as follows: 50 DM 0., + Dhs Wpeak . W - 2 - + (7) tan 6 tan 0 where: Wpoak - width of peak grain depth, m (ft) W - storage width, m (It) Dpoak - peak grain depth, m (ft) 6 . angle of repose of grain, deg Dls . grain depth at lower side wall, m (it) D,” - grain depth at higher side wall, m (ft) The calculation for length of peak grain depth exchanges side wall depths for end wall depths and storage width for storage length. The capacity of a grain storage is calculated by dividing the storage into twelve volumes (Figure 8). This method is a refinement of the method suggested by Midwest Plan Service (1987) in which the grain storage is divided into three volumes. A storage profile with different grain depths on the walls requires this enhanced procedure to more accurately estimate storage capacity. The grain depth on the highest wall determines the perimeter for the base volume calculation. The length of the grain mass extension from the base volume to the lower side wall is calculated as follows: DIM. DI. LB...“- tan 0 (8) where: L. . length of lower side wall extension less than grain depth at highest wall, m (It) D“w - grain depth at highest wall, m (It) Du - grain depth at lower side wall, m (It) 0 - angle of repose of grain, deg Grain depth at the lower side wall is replaced by the grain depth at the other two walls to determine the length from the base volume to the walls. The horizontal Dha Db Dlto Dlo V1 v2 v3 V4 v5 V6 v7 V8 v9 V10- V11- V12: Figure 8. Grain storage divisions for volume calculation of flat storages. 51 storage width, m (ft) storage length, m (It) grain depth at higher side wall, m (It) grain depth at lower side wall, m (It) grain depth at higher end wall, m (it) grain depth at lower end wall, rn (It) base volume. at3 (lt3) middle peak volume, m3 (ft3) end peak frustum volume. m3 (ft3) lower side wall extension volume, m3 (ft3) higher end wall extension volume. m3 (ft3) lower end wall extension volume, m3 (ft3) higher corner extension base volume, m3 (ft3) higher comer extension volume, m3 (ft3) higher comer extension peak volume. m3 (ft3) lower corner extension base volume, m3 (ft3) lower comer extension volume, m3 (ft3) lower comer extension peak volume, m3 (ft3) 52 length from the peak grain depth to the highest wall grain depth is calculated as follows: Dpaak ' th Lshw "' (9) tan 6 where: Lu." - length of slope from wall with highest grain depth, m (it) Dpeak - peak grain depth, m (It) Dm - grain depth at highest wall, m (It) 6 - angle of repose of grain, deg The grain mass above the base volume is divided into a frustum and middle peak. The area of the top and bottom surface of the frustum is determined as follows: AR-(W-Lb-Lm-ZmeF (10) and AR, .. (w - Lis - LN)2 (11) where: A" . area at top of fmstum, m2 (it?) A,b - area at base of frustum, m2 (ft?) W - width of storage, m (ft) L. - length of lower side wall extension less than grain depth at highest wall, m (It) Lm - length of higher side wall extension less than grain depth at highest wall, m (It) Lshw - length of slope from wall with highest grain depth, m (It) Volume equations for the twelve grain volumes depicted in Figure 8 are as follows: V1-Dm(W-LB-Lm)(L-Lb-Lhe) (12) L - Lb ' L“ ' W + LB + th VZ 3 (D 2 cm) (W - th - Lls + wp) (13) peak ' 53 (Ag, + A1. + (Am A191”) (Dpeak - 0m) V3 - 3 (L - L..- I...) L. V4 I (0m + DIS) 2 (w - L. - L...) L... V5 8 (Um -I- 0“,) 2 (w - L. - L...) L. V6 - (th + D“) 2 V7 ' Dis '12 Lisa (011w ‘ Dis) Va .. 3 L... - L. V9 =- L,‘ -------- (DI3 + Dm) 2 V10 ' Dls L132 L132 (Dm - Db) V11 3 3 L..-L. V12 = LI: """ (Db ‘I’ Dle) (14) (15) (15) (17) (18) (19) (20) (21) (22) (23) where: V1 II V2 . v3 . v4 .- V5 - V6 .- v7 .- V8 - v9 - V1o .- V11 ' V12 .- D"W - W . L . Ll3 . th . L19 .- Lh. . Omsk . Weak . Afl .- A'b . 54 base volume, 1113 GP) middle peak volume, m3 (ft3) end peak lmstum volumes, m3 (ft3) lower side wall extension volume, m3 (ft3) higher end wall extension volume, m3 (ft3) lower end wall extension volume, m3 (ft3) comer base volume, m3 (ft3) corner peak volume, m3 (113) higher corner extension volume, m3 (It?) corner base volume, m3 (ft3) corner peak volume, m3 (ft3) lower corner extension volume, m3 (lt3) grain depth at highest wall, m (ft) width of storage, m (It) length of storage, m (ft) length of lower side wall extension less than grain depth at highest wall, m (It) length of higher side wall extension less than grain depth at highest wall, m (ft) length of lower end wall extension less than grain depth at highest wall, m (It) length of higher end wall extension less than grain depth at highest wall, m (It) peak grain depth, m (ft) width of peak grain depth, m (It) area at top of frustum, rn2 (ftz) area at base of fmstum, m2 (It?) D,s - grain depth at lower side wall, m (ft) Dm - grain depth at higher side wall, m (it) D"3 - grain depth at lower end wall, m (it) D", - grain depth at higher end wall, m (It) Fortraditional units, the sum of the equations 12 through 23 is divided by the factor 1.244 to determine storage capacity in bushels. The filling angle of grain used in volume calculations affects the peak height and storage capacity. The filling angles used are: 25 degrees for shelled com, 28 degrees for soybeans, 23 degrees for wheat and 23 degrees for grain sorghum. 55 Some small grain storages with very shallow grain depths will result in more ducts than are commonly considered necessary. In an attempt to minimize this problem two threshold values of 106 m3 (3000 bu) of grain and 1.8 m (6 ft) peak grain depth were used as minimum requirements for designing an aeration system. If the grain capacity or peak depth are less than these thresholds the user is informed of the program limitation. DUCT PLACEMENT This procedure of the calculations component performs the time-consuming task of determining the position of ducts in the storage based on air path ratios as described by Holman (1960) and Burrell (1974). The aeration design program uses an air path ratio of 1.5 to place ducts, with the exception that the air path ratio from the first or last duct to the nearest wall may be greater. The allowable air path ratio to the wall is 1.8 if grain depth at wall is 1.5 m (5 ft) or higher or 2.0 if grain depth is less than 1.5 m (5 it). This modified air path ratio method is a combination of air path ratios given by Holman (1960) and Burrell (1974) When comparing the air path ratio of 1.5 with the higher air path ratios or the guidelines given by Midwest Plan Service(1987), the latter methods essentially assume that some grain near a wall will cool or warm naturally by conduction. However, no guidelines have been published that could be incorporated into a program to determine the amount of grain which does not need to be aerated. Data is needed to support the hypothesis that grain within a certain distance of an outside wall, or grain up to a certain depth, will cool or warm naturally by conduction. If this data were available grain near an outside wall or in shallow depths could be ignored when designing an aeration system. 56 The duct placement procedure performs the following tasks: 1) estimates number of ducts for storage 2) places estimated number of ducts based on air path ratio factors 3) calculates the air path ratio from the first and last ducts to the nearest wall 4) compares calculated air path ratio to guidelines 5) if needed, adjusts estimated number of ducts and repeat steps 2 through 5 An estimate of the number of ducts required by the storage is determined by calculating the average grain depth in the grain section opposite the direction of the duct runs. The following equation is used for estimating average grain depth with lengthwise placement of ducts. DbTDpeak Dm+Dpeak WM 0M1» (L.+L‘m)+ 2 (thTLshw) 2 D .- (24) W where: D," - average depth of grain, m (It) Wpeak - width of peak grain depth, m (It) Dpoak - peak grain depth, m (It) Dls - grain depth at lower side wall, m (ft) '1. - length of lower side wall extension less than grain depth at highest wall, m (It) Lahw - length of slope from wall with highest grain depth, m (ft) Du - grain depth at higher side wall, m (It) L... - length of higher side wall extension less than grain depth at highest wall, m (It) W - width of storage, m (It) For widthwise placement of ducts, storage length replaces storage width and end wall lengths and depths replace side wall lengths and depths. The average grain depth is divided by the storage length for widthwise placement. Once the number of ducts has been estimated, the ducts are positioned in the storage. Ducts are placed starting in the center of the storage. It the 57 number of ducts is odd then the middle duct is placed directly under the center of the grain peak If the number of ducts is even, then the boundary of grain aerated by the two center ducts is directly under the grain peak. The borders of the area aerated by a duct are determined by calculating the distance from a previously placed duct to the border or from a previously established border to a duct. The air path ratio method is used to determine when a border is reached. To determine positioning of a duct, the previously known duct or border position is incremented by a factor of 7.6 cm (3 in.) until the air path ratio is equal to or slightly less than the design air path ratio. This process continues until the estimated number of ducts is placed or a duct is placed within 0.9 m (3 ft) of an edge of the storage. After the ducts are placed, based on the 1.5 air path ratio, the air path ratios to the side walls are calculated. "These ratios are compared to the allowable side wall air path ratios. If the calculated air path ratio is not equal to the design ratio, the estimated number of ducts is incremented or decremented by one and the ducts spacing algorithm is used to place the revised number of ducts. This procedure continues until the outside air path ratios equal the design ratios or until the number of ducts has been both decremented and incremented. The higher number of ducts is used to perform a final duct spacing. If the number of ducts is set by the program user, the duct spacing algorithm uses the 1.5 air path ratio to place the desired number of ducts. If the user has selected more ducts than can be placed in the storage with the 1.5 air path ratio, the number of ducts is decremented by one and the duct placement algorithm is used to place the revised number of ducts. The outside air path ratio is calculated and recorded for display to the user. If the outside air path ratio is higher than the appropriate allowable value of 1.8 or 2.0, a warning message is 58 displayed to the user. The outside air path ratio from the outermost duct to the outside wall is calculated as follows: W ' Pd + DW R I (25) 08h where: Rap - air path ratio w . width of storage. mlft) p d .. duct distance from lower wall, m (ft) D =- grain depth at wall, m (It) W Dsh - shortest distance from duct to grain surface. m (it) DUCT LENGTH The length of a duct is determined by first calculating the distance from the end walls that the duct should be placed. A reference point for offsetting the perforated duct section from the end wall is determined by calculating the shortest distance from the duct to the grain surface in the grain profile section perpendicular to the direction of duct run. Beginning at the end wall and incrementing the distance from the wall, the shortest distance in the direction of the duct run is compared to the reference point. When the two distances are equal, the end of the duct is placed at that point. The duct length is the difference between the storage length (in the direction of the duct run) and the sum of the perforated duct offset from the two end walls. In some grain storages the duct length calculation can result in a value of zero. In this case, the depth of the storage varies too greatly in the direction of the duct run to effectively aerate the grain. Possible solutions are to change the direction of duct run or provide a flatter grain profile. 59 FAN PLACEMENT AND SIZE Sizing of a fan or fans for a duct consists of determining the number and positioning of fans for a duct and sizing the fan based on a static pressure estimate and airflow requirement. The aeration system design program allows one or two fans per duct. One fan may be placed at one end of a duct or at the middle of a duct. Fan placement at the middle of a duct is permissible if the duct is the first or last one in the storage. With two fans, one fan is placed at each end of the duct. The determining factors for fan placement are the arrangement desired by the user and the maximum length of a duct served by an air source. The user may choose middle and end placement, end placement only or middle placement. Middle and end placement results in the fans being arranged in the manner which requires the least number of fans. The various recommendations for the maximum length of duct served by an air source were listed in Chapter II. The aeration program uses 18.3 m (60 ft) for plastic duct (Brook, 1983) and 24.4 m (80 ft) for metal duct (Cloud and Morey, 1980; MWPS, 1987). If the perforated duct is longer than the maximum length allowed from one fan either one fan must be used at each end of the duct or one fan must be placed at the middle of the duct. An estimate of the static pressure of the grain is calculated according to the American Society of Agricultural Engineers standard 0272.1 (ASAE, 1987) (equation 1). The shortest distance from the duct to the grain surface is used for bed depth (Holman, 1960). A packing factor for adjusting static pressure to reflect field conditions is used as referenced from Midwest Plan Service (1987) in Chapter II. The estimated static pressure is increased by 0.06 kPa (0.25 in. H20) for supply tube losses and 0.06 kPa (0.25 in. H20) for each tee or elbow connector in the supply tube. It the estimated static pressure is still less than 60 0.125 kPa (0.5 in. H20), the static pressure is increased to this factor, as it is usually the threshold for fan performance data. The required airflow is based on the user determined airflow rate and the volume of grain served by the duct. The default value for airflow rate is 0.12 m3/min/m3 (0.15 ft3/min/bu). The same equations used to calculate capacity of the storage are used to calculate the capacity of the volume served by the duct. Fan curve data for 11 axial and 5 centrifugal fans from Brook and Harmsen (1982) are stored in the aeration program. Equation 3 (Brook and Harmsen, 1982) is used to estimate airflow output of a fan at the estimated static pressure. The estimated airflow was increased by five percent as a sizing allowance for accepting lower airflow instead of using the next larger size fan. The required airflow is compared to estimated airflow of available fans, beginning with the smallest fan, until the estimated airflow is greater or equal to the required airflow. If the required airflow is greater than the estimated airflow of the largest fan a message is displayed to the user noting this fact. Once a fan is selected, the operating static pressure and airflow are re-estimated to approximate operating conditions. DUCT SIZE Duct size is based on the allowable airflow velocities in the duct and exiting the duct. The aeration program uses 457 m/min (1500 ft/min) (Brook, 1979; MWPS, 1987) maximum airflow velocity in the duct and 7.6 m/min (25 ft/min) (Cloud and Morey, 1980) exit velocity. The maximum velocities were increased by five percent to allow a slight increase in airflow velocity rather than use the next larger duct. Minimum cross-sectional area and surface area of the duct are determined from equations 4 and 5, respectively. The required duct diameter for cross-sectional area was calculated as: 61 duct diameter m (It) - (cross-sectional area m2 (it?) /3.1416)1’2 * 2 (26) and the required duct diameter for surface area was calculated as: duct diameter in (ft) - surface area m2 (It?) / (duct length ' 3.1416) (27) The larger of the two calculated diameters is used to specify duct size. SUPPLY TUBE PLACEMENT AND SIZE Supply tubes are sized to channel air from the fan on the outside of the storage to the duct. Supply tubes are placed in accordance with the fan arrangement. Supply tube diameter is determined based on the allowable airflow velocity in the supply tube of 610 m/min (2000 ft/min) (Foster and Tuite, 1986; Holman, 1960) plus the five percent factor used in sizing ducts. Equations 4 and 26 are used to specify the supply tube diameter. Length of the supply tube is the same as the offset of the perforated duct from the end of the storage. DESIGN DRAWING The design drawing component of the aeration system design program prints the component specifications and an aeration system plan. A program was written in the 'C' language for the design drawing processor. One function of the program is to print the fan, duct and supply tube specifications based on the values determined from the calculations component (Figure 9). As discussed in Chapter III, parametric computer aided drafting software (Synthesis and AutoCAD commercial software products) was used to generate the custom aeration system design drawings. The generic master drawings were prepared according to the instnictions in the Synthesis user's guide. Three master drawings were initially planned, but due to problems in rotating text and 62 AERAIION SYSTEM COMPONENT SPECIFICATIONS for Dennis Natson The accompanying floor plan of the grain storage illustrates the placement of the components. Ducts are labeled with numbers and fans are labeled with letters. The following table lists the specifications of each component. DOC! FAN # sire # size cfm. sp connector size 1 12" x 81' a 12" 0.33111: 1740 0.6 14" x 9' 2 21" x 53'-6" .1 16" 1.50hp 3773 0.5 21" x 23'-3" 3 21" x 53'-6” A. 16" 1.50hp 3773 0.5 21" x 23'-3" 4 12" x 81' A 12" 0.335;: 1740 0.6 14" x 9' cam -- airflow in cubic feet per'mdnute required from.fan. sp -- Operating static pressure of the fan in inches of water. Note: 3? (base point) on the following drawing is the corner at which the lower side wall and lower end wall:meet. Figure 9. Sample component specification listing generated by the aeration system design program. 63 adding optional dimensions, eleven master drawings were required to generate the design drawings. The drawings resemble typical computer aided drafting (CAD) drawings with the exception that dimension text is replaced with variable identifiers. The variable identifiers consist of a '$' and digits (e.g. $123). Some of the dimensions on the master drawings are hidden. These hidden dimensions are used to place and size certain entities. Table 10 lists the master drawing names and descriptions. Table 10. Master drawings for the aeration system design program. Drawing Name Drawing description BASE rectangular outline of grain storage DUCT perforated duct to be placed horizontally on drawing DUCTV perforated duct to be placed vertically on drawing FAN fan and supply tube to be placed horizontally on drawing FANV fan and supply tube to be placed vertically on drawing DlMHO dimension for middle fan placement from end wall at bottom of drawing DIMH1 dimension for middle fan placement from end wall at top of drawing DIMVO dimension for middle fan placement from side wall at left of drawing DIMV1 dimension for middle fan placement from side wall at right of drawing TEXT H label text oriented horizontally for middle fan placement TEXTV label text oriented vertically for middle fan placement The primary master drawings are the storage outline (Figure 10), perforated duct (Figure 11) and fan and supply tube (Figure 12). 64 $80 $10 B P $10 - storage width $20 - storage length Q - reference point for inserting component drawings Figure 10. BASE master drawing: rectangular outline of grain storage. 65 $236 L l 9.1 g 5.}: ‘6’ l saoo g I II I in L 52 40 I _ saeo L _. $238 $200 -- label for duct number $212 -- duct radius (hidden dimension) $220 - duct length (hidden dimension) $232 - duct offset from edge of storage parallel to duct $235 - offset of upper dimension line extension from duct center (hidden dimension) $236 - offset of upper dimension line extension from edge of storage (hidden dimension) $237 -- offset of lower dimension line extension from edge of storage (hidden dimension) $238 - length of dimension line extensions (hidden dimension) $240 - duct offset from edge of storage perpendicular to duct reference point for inserting into base drawing Note: all dimensions on this drawing are hidden from program user except $232 and $240. Figure 11. DUCT master drawing: perforated duct to be placed in drawing. 66 __ 3319 13301 I 3’, is t 3314‘ 3 ' it " 2' L‘ saool— ‘3 ‘3 e' re—r——' n ‘2 (u T'i 81 g D ‘5’ $330 s33_a . seals $300 - label for fan A $301 -- label for fan B $312 .. radius of fan A (hidden dimension) $314 -- length of fan B (hidden dimension) $317 - radius of Ian A (hidden dimension) $319 -- length of fan B (hidden dimension) $322 -- radius of supply tube A (hidden dimension) $327 -- radius of supply tube B (hidden dimension) $330 -- length of supply tube A (hidden dimension) $332 - length of perforated duct (hidden dimension) $335 - Iength of supply tube B (hidden dimension) $340 - offset of fans (hidden dimension) -- reference point for inserting into base drawing Note: all dimensions on this drawing are hidden from program user. Figure 12. FAN master drawing: fan and supply tube to be placed in drawing. 67 A second function of the design drawing processor is to generate a drawing specification file (FIQUI‘B 13) for use by Synthesis in generating a custom drawing from the various master drawings. This function assigns values to variable identifiers, determines which master drawings to use in the custom drawing and places the master drawings in the custom drawing. Appendix F contains the 'C' code listing of this function. The final function of the design drawing processor executes the Synthesis and AutoCAD programs. Synthesis uses the drawing specification file to generate the custom drawing and AutoCAD displays and prints the drawing (Figure 14). After the drawing is printed, the design drawing processor relinquishes program control to the framework. MANAGEMENT RECOMMENDATIONS The management recommendations component of the aeration system design program consists of an ASCII file of recommendations text and a set of rules for printing recommendations. The recommendations were divided into four sections of: 1) user inputs listing, 2) flat storage comments, 3) specific plan comments and 4) grain management comments (Figure 15). The user responses are summarized on the management recommendations printout to attach the plan to a specific set of design parameters. Flat storage comments define flat storage and its appropriate usage and term of storage. Comments on the specific plan are important to the user in implementing the plan successfully. These comments include recommendations on vapor barrier, roofing, post size and spacing and grain liners. Management comments include the need for clean grain for good air distribution, grain observation, temperature 68 [AERATION DESIGN DRINING SPECIFICATION FILE [for . VILUI 600000000 DIMENSION TEXT aseeeeeseeeeeseeeseeeeeeeeteee ROTATION 0.0 9.50 9.50 1.0 1.0 0 50.00 0.00 1.0 1.0 O 50' 50.00 0.00 1.0 1.0 0 Figure 13. Partial listing of a drawing specification file for an aeration system design. 69 100’ 50’ _, 'l l_' XI 2? 3:, O‘jL_ . Duct4_ a 9’-6" J! A 1 Duck 13] 23'-3' J a. \D A Duct 2 T'— 1 ’ f 23'-3' _| 5 vi 5, l"— _ Duct 1 cu :91 9'-6'l Jl_°_‘.lL._ __._l BP L 50' fl) Figure 14. Sample aeration system plan displayed and printed for user of aeration system design program. 70 This aeration system has been designed for: Dennis Watson Michigan State University 106A Farrall Hall E. Lansing, Michigan 48824 123-456-7890 The following listing summarizes information about the aeration system: Grain -- Building ~- Construction -- Post spacing -- Grain liner information -- Storage size -- Wall depths: higher side wall -- lower side wall -- higher end wall -- lower end wall -- Maximum piling height -- Bushel capacity -- Actual peak height -- Width of peak -- Ducts -- Fan arrangement -- Fan type -- Duct direction -- Duct type -- Airflow rate -- shelled corn existing post frame 80 not requested 60.0' by 100.0' 6.0' 6.0' 6.0' 6.0' 16.0' 54517 16.0' 17.1' computer selected 4 end or middle placement axial lengthwise round metal 0.15 cfm/bu GENERAL COMMENTS ON FLAT STORAGES: The use of buildings for grain storage is not recommended for more than 1 to 2 months storage if not equipped with an adequate aeration storage. The use of buildings for grain storage when adequate aeration is installed is not recommended for storage of grain past late spring. Figure 15. Partial listing of management recommendations from an aeration system design. 71 SPECIFIC COMMENTS ON THIS AERATION PLAN: The grain will be piled, at most, 6.0 feet on the side wall of your building. With the posts spaced 8 feet on center, a post size of at least 6" x 6" is required. The smaller post dimension must face the grain. Higher grain depths or smaller posts will likely to cause structural damage to the building. GRAIN MANAGEMENT COMMENTS: The design airflow may be greater than the effective delivered airflow. Grain with excess amounts of fines or foreign material will increase the static pressure caused by the grain. The change in static pressure will lower the delivered airflow for that general area of the grain storage. The fans should be operated for upward airflow in order to help ensure as uniform an airflow as possible along the length of the ductls). The upward airflow also helps the management of the cooling phase by allowing observation of the air exiting the surface of the grain mass which will help show the progress of cooling in different areas of the storage. Proper management practices are essential to successful storage of grain. Grain should be clean, dry and cool to insure the maintenance of quality during storage. A regular inspection of the grain during the storage period will help to avoid storage problems. For more details, see Michigan State University Cooperative Extension Service bulletin E-1431. Figure 15. (Cont'd) 72 monitoring systems, fan operation, fan types, grain inspection and aeration management procedures. The text file of management recommendations and the source code of rules for printing the recommendations are in Appendices G and H, respectively. CHAPTER V EVALUATION OF AERATION SYSTEM DESIGN PROGRAM A stnictured expert review process was used to evaluate the aeration system design program. Persons experienced with aeration system design reviewed the program and compared it with their own approaCh and provided an evaluation of the aeration system design program. Reviewers were extension specialists at land grant universities, agricultural engineering consultants and industry representatives. The purpose of evaluation was two-fold: first, to evaluate the technical content of the program for validity; and second, to evaluate the usability of the program. This chapter discusses the evaluation objectives, describes the evaluation instniments and procedure, reports evaluation results and discusses implications of the evaluation. EVALUATION OBJECTIVES Objectives of the evaluation process guided development of evaluation instruments. The following description of objectives is divided into technical and usability aspects of the evaluation process. TECHNICAL EVALUATION OBJEC‘HVES The technical content of the computer program on aeration system design was reviewed to determine its validity. Objectives of the technical evaluation were to determine concurrent validity, construct validity, content validity and sensitivity. 73 74 Concurrent validity is determined by relating a test to a criterion measure administered at about the same time (Borg and Gall, 1971). Two case studies of aeration design problems were described and reviewers were asked to solve them by their usual method and then to use the design program to solve the problems. Constnict validity is the extent to which logical and theoretically consistent constructs are represented (Borg and Gall, 1971 ). The accuracy of the underlying logical structure of design guidelines and equations was tested. Reviewers' comments and solutions to case studies were examined to determine the accuracy of the program's logical structure. Content validity is the degree to which items or components, in this case the questions asked of the user, are pertinent to solving the problem for which the program was designed (Borg and Gall, 1971). Appropriateness of information requested of the user to solve the problem was determined by reviewers' comments and responses to a questionnaire. Sensitivity refers to the degree to which the program can utilize incomplete or poor information and still produce an acceptable design. The aeration design program includes a 'help' facility which program users can activate to learn why a question was asked and what needs to be considered to respond. Reviewers rated the sufficiency of help information for assisting a user in answering questions. USABILITY EVALUATION OBJECTIVES An important measure of the success of a design program is usability. As design programs are seldom used on a regular basis, they should be easy to use and time spent relearning a program should be kept to a minimum. Although a user may initially need to reference a manual to run a program, the user interface should be logical and easy to remember. 75 Objectives of the usability evaluation were to determine ease of use, conveyance of information, pertinence of illustrations and usefulness of design drawings. To evaluate ease of use, reviewers' comments and responses to questions requesting an 'ease of use' rating were used. An engineering design program must convey information to a user in a concise manner to eliminate ambiguities that result in a poor plan. Reviewers rated the effectiveness of information conveyance through text and graphics. Illustrations were used in the program to increase the efficiency of information conveyance. Illustration content was reviewed to determine appropriateness of the illustrations. The aeration system design program produces a design drawing and management recommendations which the client can use to implement the aeration system design. Reviewers rated the usefulness of the design drawing and management recommendations. EVALUATION INSTRUMENTS AND PROCEDURE Evaluation instruments and procedures were devised for evaluation of the aeration system design program. The evaluation procedure included developing evaluation instruments, contacting reviewers prior to on-site evaluation and conducting the on-site evaluation. EVALUA‘RON INSTRUMENTS The first set of evaluation instruments consisted of aeration system design case studies. Two case studies were prepared for evaluating concurrent and construct validity (see Appendix I for instruments). Reviewers completed the case studies, using their usual procedures, before the on-site phase of the evaluation. The two case studies were similar in duct placement, but differed in storage profile, duct direction, duct type and fan placement. For the reviewers' 76 convenience, five worksheets were prepared for each case study as listed in Table 11. Table 11. Description of worksheets included with case studies. Worksheet Description and Usage 1 case study description including storage specifications and ‘ equipment preferences 2 cross-sectional drawing of case study with grid for clarification of grain profile 3 floor plan (with grid) of case study storage for sketching component placement 4 table of component specifications for listing design results 5 recommendations list for listing any design implementation and management recommendations for the case study The worksheets made it easier for the reviewers to complete the case studies and provided a common format for summarizing results. A questionnaire about aeration system design guidelines was included with the case studies. This questionnaire was used to determine the source of differences between a reviewer's design and the program's. Responses to this questionnaire summarized the reviewer's method for determining duct placement, duct length, fan size, duct size and supply tube size. Five questionnaires were devised to meet the technical and usability evaluation objectives (see Appendix J for questionnaires). These questionnaires 77 were used during the on-site evaluation. A description of the questionnaires in the order presented to the reviewers follows: 1 rating of design results - design results of the program were compared to reviewers' results and the differences were rated as "none", "minor“, "moderate" or ”substantial”. 2 explanation of moderate or substantial rating - the reason a design result was rated as moderately or substantially different from the program result was explained on this form, and any suggestions for changing the program were made. 3 review of design guidelines - a reviewer's agreement or disagreement with design guidelines used in the program was recorded, and alternative guidelines were requested. 4 review of response screens - reviewers were asked to respond "yes" or "no” to the following questions about a response screen of the program and were given a chance to make suggestions or comments. Is this information you typically ask of a client? Is this information readily available to the client? Is the question worded adequately? Is the help information sufficient to assist a client in answering the question? 5 usability evaluation - reviewers were asked to rate the usability of the program in terms of the user interface, information conveyance, design drawing and management recommendations. Questionnaires one and two address concurrent validity by having the reviewers directly compare their designs to the program results. Results of the concurrent validity test and questionnaire three were used to determine construct validity. If any results of the concurrent validity test had not been 78 explained by differences in design guidelines a potential problem with construct validity would have existed. Content validity and sensitivity were measured with questionnaire four. Questionnaire five addressed the usability of the program. CONTACT WITH REVIEWERS Nine reviewers were selected to evaluate the aeration system design program. Five reviewers were associated with extension work in agricultural engineering at universities and four were associated with aeration system component manufacturers as listed in Table 12. Table 12. Reviewers for aeration system design program. Reviewer Name Employer Position Title B. A. McKenzie, PH.D. Purdue University Professor and Project Leader G. H. Foster, PH.D. Purdue University Professor emeritus W. H. Peterson, PH.D. Univ. of Illinois Professor G. C. Shove, PH.D. Univ. of Illinois Professor and Division Leader M. Hall Univ. of Illinois Extension Agricultural Engineer W. Alterrnatt Hancor, Inc. Manager of Marketing & Sales Engineering J. McNall Hancor, Inc. Applications Engineer D. Hansen Aerovent, Inc. Engineering Manager S. Ganser Aerovent, Inc. Design Supervisor On-site evaluations by university reviewers were scheduled at both universities. Date and time of the visits were confirmed approximately eight weeks in advance. The case studies were sent to the reviewers four weeks before the on-site visit and a subsequent contact to verify plans was made two weeks prior to the visit. 79 On-site evaluations by industry representatives were conducted in the Interactive Computer Graphics Laboratory of the Agricultural Engineering department of Michigan State University. Visits were scheduled two to four weeks in advance and case study material was sent as soon as the visits were scheduled. A subsequent contact was made the day before the scheduled visit to verify plans. ON-SITE EVALUATION On-site evaluations were scheduled for three hours plus a luncheon. The agenda for the evaluation meetings is presented in Table 13. Table 13. Agenda for on-site evaluation of aeration system design program. Relative Time Activity 0:00 opening remarks on research project 0:10 introduction to aeration system design program 0:20 program demonstration with case study 1 0:35 reviewers use program with case study 2 plus their case studies rating of design results interaction with reviewers discussing differences in results 1:30 explanation of moderate or substantial ratings 1:45 review of design guidelines 2:00 review of response screens 2:30 usability evaluation 3:00 luncheon impromptu discussion of program and aeration system design The evaluation procedure progressed according to the agenda under the direction of the researcher. At times, discussion was cut short to keep on schedule. Two microcomputers were taken to the Purdue University and 80 University of Illinois sites to insure that proper equipment would be available. One computer was used for the evaluation sessions held at Michigan State University. During the sessions, notes were made of pertinent comments made by the reviewers. Two people familiar with the program directed reviewers during the evaluation process, except for the session with the people from Hancor when only one was available. The luncheons, after the evaluation session, provided a relaxed environment for discussing the program and aeration system design. RESULTS OF EVALUATION Responses to the questionnaires were quantified and summarized (see Appendix K for details). Results of the technical content and usability evaluation are presented here. TECHNICAL EVALUATION Utilizing outside experts in the technical evaluation process was very beneficial, as reviewers were cooperative and shared their technical expertise in aeration system design. The technical evaluation consisted of concurrent validity, construct validity, content validity and sensitivity components. Concurrent Validity Questionnaires for rating design results and explanations of moderate or substantial differences between the reviewers' and the program's results were used to determine concurrent validity. The reviewers' ratings of the design results are summarized in Table 14. 81 Table 14. Summary of reviewers' ratings of design results. Differences’ Design Result None or Minor Moderate or Substantial number of ducts 7 2 placement of ducts 3 6 duct diameter 6 3 duct length 3 6 number of fans 3 5 fan size 4 4 connector size 6 3 totals 32 29 'Some reviewers did not respond to every question. Three of these categories received more ratings of "none" or "minor" differences than "moderate" or "substantial” and three categories received more ratings of "moderate" or ”substantial” differences. "Moderate” or ”substantial" differences were associated with differences in choice of design guidelines between expert reviewers and the design program. number of ducts The two "moderate” or "substantial” differences in the ”number of ducts" category were caused by the program placing too many ducts in shallow storages and reviewers using a 1.5 air path ratio for the outside ducts compared to the 1.8 or 2.0 ratio in the program. The program does have limitations in placing ducts in shallow storages. In shallow storages, such as one with a side wall grain depth of near zero and a width of 9 m (30 ft) or less, the air path ratio method results in more ducts being placed than are normally considered reasonable. 82 Reviewers suggested ignoring shallow grain depths to overcome the problem with over-design in shallow storages. A similar guideline was desired when developing the program, but no research data were available to establish a depth of grain that could be ignored. Two reviewers reported ignoring grain depths less than 0.9 m (3 ft) in their designs. Other reviewers suggested that grain depths of 1.2 or 1.8 m (4 or 6 it) could be ignored in designing an aeration system. placement of ducts The six ”moderate” or "substantial” difference ratings in the "placement of ducts” category were primarily caused by the use of a higher air path ratio from the outside wall to the nearest duct in the program and the accuracy with which the ducts were placed. Three of the six reviewers with "moderate” or ”substantial” difference ratings did not think the program should be changed. Two reviewers wanted the program to include extra capabilities, such as allowing an expert to change the air path ratio or to consider a tarp-covered pile. The other suggestion for change was related to ignoring shallow grain depths, as discussed above. On the questionnaire for design guidelines included with the case studies, reviewers reported using the following methods for placing ducts: - spacing approximately equal to grain depth - spacing no farther apart than minimum grain depth served by duct - 1.5 air path ratio for center ducts, 2.0 or 3.0 air path ratio for outer ducts - 1.5 air path ratio based on average depth of grain served by duct duct diameter ”Moderate" or "substantial” difference ratings in the "duct diameter" category were caused by reviewers 1) varying the size of a duct by using a smaller diameter at the ends; 2) allowing duct velocities greater than 457 m/min (1500 83 ft/min) when grain depth was 9 m (30 ft) and 3) sizing the duct based on required airflow rather than the airflow delivered by a selected fan. On the design guideline questionnaire, reviewers reported allowing 10, 20, and 25 percent increases in duct velocity in order to recommend use of a smaller duct size. One reviewer said no increase was recommended. The program allowed a 5 percent increase. Six of nine reviewers had ”moderate” or “substantial” differences in the ”duct length" category. These differences were caused by a difference in the guidelines used to determine the distance to offset a perforated section of duct from an end of a storage. The program used a rule which required air paths to be as equal as possible. Based on the following responses to the design guideline questionnaire; reviewers typically allowed a larger variation in air paths: - distance from perforated duct to end wall about equal to spacing from side duct to side wall - air path ratio from duct to grain surface at end wall equal to longest air path ratio laterally from duct - judgment call assuming that grain near the edge of a pile will cool adequately by conduction without aeration - distance from duct to end wall equal to end wall grain depth - judgment call that places the end point of a duct so that the shortest air path is approximately 75 percent of the maximum depth on a center level fill. If storage is totally conical, try to orient ducts so that separate systems supply shallow vs. deep sections One reviewer, who uses plastic aeration tubing for most designs, used tubing under shallow grain with one-half the perforated area of that placed in the middle of the storage. This method assumes that the perforated area 'throttles' the airflow. 84 number of fans The number of ”moderate” or "substantial" ratings for the ”number of fans" category was related to the allowable length of plastic tubing from a fan and the number of ducts one fan was allowed to supply. The program's limit of 18.2 m (60 ft) of plastic tubing from a fan was less than the reviewers allowed. With a storage profile such as that used for case study 1, the 18.2 m (60 ft) length resulted in the program placing a fan at each end of the ducts. Forthis case study, the reviewers used one fan and allowed a longer length of plastic tubing from a fan. Some reviewers used one fan to supply multiple ducts; an alternative the program did not consider. fan size ”Moderate" or ”substantial” differences in fan size were caused by reviewers using one fan for multiple ducts, being unaware of the small fan size used in the program and having data (not included in program) to estimate static pressure of plastic tubing. The length of grain used to estimate static pressure of grain varied among reviewers. Two used the grain depth directly above duct, two used peak grain depth served by a duct and one used the longest air flow path. One reviewer allowed no airflow reduction to recommend a smaller fan, while others allowed 10 and 15 percent reductions compared to 5 percent used by the program. connector size "Moderate" or ”substantial” differences in connector size were related to a difference in guidelines for determining the distance to offset the perforated section of duct from the end of the storage as discussed above and to a reviewer misinterpreting the term 'connector' when completing the case studies. 85 Construct Validity Reviewers registered their agreement or disagreement with some key design guidelines used in the program (summarized in Table 15). The reviewers generally agreed with the values used in the program. One notable exception was the maximum length of plastic aeration tubing from a fan, which the reviewers felt should be increased to 22.9, 24.4 or 30 m (75, 80 or 100 ft). Three reviewers also suggested the maximum length of a metal aeration tube from a fan be increased to 30 m (100 it). Other suggestions were to use 1) 1.2m (4 ft) as the minimum grain depth on a wall to be considered deep enough for determining the air path ratio to use; 2) static pressure data for plastic tubing to estimate static pressure for a connector; 3) 0.1 kPa (0.5 in. H20) or 10 to 15 percent of the total static pressure, for static pressure of a turn in a connector or duct; 4) no minimum capacity as a threshold for designing an aeration system for a storage and 5) 1.5 or 1.8 m (5 or 6 it) as the minimum distance to place a duct from a wall parallel to the duct. 86 Table 15. Summary of reviewers' agreement with design guidelines. Program Number’ Design Factor Value Agreed Disagreed air path ratio for middle ducts 1.5 8 0 minimum grain depth on wall to be considered deep (ft) 5 7 1 air path ratio to outside with shallow grain depth 2.0 8 0 air path ratio to outside with deep grain depth 1.8 8 0 maximum length of plastic aeration tube from fan (ft) 60 1 6 maximum length of metal aeration tube from fan (ft) 80 4 3 minimum static pressure for fan sizing (in. water) 0.5 8 0 static pressure of connector (in. water) 0.25 6 1 static pressure of turn in connector or duct (in. water) 0.25 5 2 minimum bushels to design aeration system (bu) 3000 6 2 minimum peak grain depth to design aeration system (ft) 6 8 0 minimum distance from duct to wall parallel to duct (it) 3 5 3 totals 74 18 'Some reviewers did not respond to every question. 87 Content Validity Content validity of the program was measured by reviewers' responses to questions about the response screens in the program. The reviewers' opinions are summarized in Table 16. In general, the reviewers said that the questions in the program were typical of questions they asked, the information to answer the questions was readily available to the clients and the questions were worded adequately. Table 16. Summary of reviewers' opinions regarding response screens. Typical Information Question Question Available Worded of Reviewer? to Client? Adequately? Response Screen YES NO YES NO YES NO client information 8 0 8 0 8 0 grain type 8 0 8 0 8 0 new structure 8 0 8 0 8 0 construction type 6 2 8 0 8 0 post spacing 6 2 8 0 8 0 structure liner 4 4 5 0' 5 3 storage size 8 0 8 0 8 0 grain depths on walls 8 0 8 0 6 2 maximum piling height 8 0 7 1 5 3 number of ducts 6 2 6 2 8 0 duct type 8 0 6 2 7 1 duct direction 8 0 8 0 7 1 fan type 5 3 7 1 7 1 fan arrangement 6 2 8 0 5 3 airflow rate 8 0 8 0 5 3 totals 105 15 111 6 103 17 'Some reviewers did not respond to every question. 88 Some reviewers did not ask all of the questions when working with a client. Four of the reviewers typically did not ask a client about the structure liner. Three did not ask the client to select a fan type. The questions about construction type and post spacing, which were used to recommend a minimum post size, were excluded by two reviewers. Two reviewers did not ask a client the number of ducts to use or the client's preferred fan arrangement. Two reviewers did not think the user would be able to determine the number of ducts to use or the duct type. One reviewer thought a client would not know the maximum piling height in a structure and one thought a client would not be able to select a fan type. Some reviewers marked eight questions as not being worded adequately. Improvements in the wording or the illustrations were suggested for seven response screens as listed in Table 17. 89 Table 17. Improvements to response screens suggested by reviewers. Response Screen Suggestion structure liner grain depths on walls maximum piling height duct type fan type fan arrangement airflow rate state that information on liners will be printed later if requested (2)' change the illustration for side depth to a leveled top (2) calculate the maximum piling height based on angle of repose and display it as the default value (2) use HDPE (High Density Polyethylene), the term preferred by industry, instead of plastic, a generic term (1) make axial the default type and provide extra spaces between axial and centrifugal types with note for user to see help if he wants centrifugal (1) include option ”one end only” or redo illustration to show fans at one end and redo illustrations to fit lengthwise and widthwise duct direction (4) ask "design airflow rate desired (cfm/bu)?" or ”air flow rate cfm/bu desired?" (1) airflow of 0.1 cfm/bu is better default (2) 'Numbers in parenthesis are number of reviewers making a suggestion. Sensitivity Sensitivity of the program was measured by the reviewers' opinions of the sufficiency of the 'help' information available to a program user as listed in Table 18. The reviewers generally responded that the 'help' information was sufficient. One exception was the 'help' information available for fan arrangement. Eight other response screens received some 'no' responses to the sufficiency of 'help' 90 information question. Table 19 summarizes comments pertinent to the 'help' information. Table 18. Summary of reviewers' opinions of 'help' information. Help information Sufficient Response Screen YES NO client information grain type new structure construction type post spacing structure liner storage size grain depths on walls maximum piling height number of ducts duct type duct direction fan type fan arrangement airflow rate 0 mummmmmooooxioooodoooxi (4)-kI\)l\)(.i)(i0l\)€3(3—*C3CDC3C)-L N _a totals 98 'Some reviewers did not respond to every question. 91 Table 19. Summary of reviewers' comments on 'help' information. Response Screen Comment client information structure liner maximum piling height number of ducts duct type duct direction fan type fan arrangement need to instruct in use of 'Enter' and 'PgDn' keys (1 )' it is not clear if a liner is needed or under what conditions a liner is recommended (1) should have instructions on calculating 'natural' piling height (1) have manager look at the computer design and then modify it a bit to conform to available sizes (1) advise that initially the 'computer selected' option should be chosen (1) change to read "This program will determine and make a recommendation for the number of ducts required to aerate the grain...” (1) depth is a limit for plastic duct (1) may need to recognize greater duct loss in plastic, also limits in the percent of open area(1) plastic ducts are not limited to shorter runs nor are they more susceptible to damage in handling (2) reference layout vs. clean-out efficiency and layout vs. number of fans and wiring cost (1) other considerations are fan location and filling method (1) choose axial in flat storage because they are more cost effective and centrifugal are not needed due to low static pressure (1 ) there are centrifugal fans available smaller than 27 in. and 5 hp (1) other considerations are fan location and filling method (1) 92 Table 19. (cont'd.). Response Screen Comment airflow rate fines need to be managed - work at uniform or central distribution; if excess accumulations cannot be avoided, consider 0.2 cfm/bu (1) include cooling time for different airflows (1) relate grain quality to grain grading parameters (1) 'Numbers in parenthesis are number of reviewers making a suggestion. USABILITY EVALUATION One questionnaire was prepared for and completed by the reviewers to rate the usability of the program. Ratings were requested for user interface, information conveyance, design drawing, management recommendations and general categories. Reviewers rated the user interface very easy to use. All reviewers agreed that beginning microcomputer users, county agents and farmers could use a program with this type of user interface. Some suggestions for improvement were to include a capability for rapidly changing responses entered early in the interview process and to have the currently highlighted response always be chosen when a screen is exited. lnfonnation conveyance with text and graphics was rated very effective by the reviewers. Reviewers responded that the illustrations would be helpful to other experts, county agents and farmers. The illustrations were rated somewhat useful for 1) involving a user in the design process; 2) considering different options and 3) amplifying the meaning of the text. The illustrations were rated very important to the accuracy of communication with the user. 93 The design drawing was rated very usable for purchasing components and installing an aeration system. Suggestions forthe design drawing were to differentiate the lines of the storage outline, supply tubes and perforated ducts to a greater extent and to relate the base point to a direction. Suggestions for the component specification listing were to 1) change the terms connector and duct to solid duct and perforated duct, respectively; 2) add total power and number of fans and estimate warming/cooling time; 3) use standard lengths and sizes and 4) draw a line under each duct size across a page. Seven of eight reviewers agreed that management recommendations are important in a program of this type. The management recommendations were rated as being very helpful to a client. Reviewers felt that the recommendations were communicated well. Reviewers stated that for the most part the correct emphasis was placed on critical recommendations and the recommendations were somewhat similar to the ones they make. Suggestions for changes to recommendations were 1) to add comments on moisture and grain temperature for continuous or intermittent operation; 2) to estimate fan operation time; 3) to list required exhaust area; 4) to recommend downward airflow and 5) to include comments on pest control, birds, rodents and insects. Reviewers agreed that the program (as is or with changes) would be helpful to them in the process of designing aeration systems. They would recommend it to county agents, farmers and aeration equipment suppliers. Half of the reviewers responding reported that the technical evaluation process caused them to think about the problem of aeration system design differently, and six indicated that they would consider changes to their current aeration system design procedure. Most of these reviewers were considering the use of different air path ratios for the outer ducts depending on the grain depth. One reviewer 94 said the evaluation process did not cause him to think about the problem differently, but he would use the program to design more accurately and to quickly try different alternatives. Reviewers made additional comments on the usability of the program. One reviewer, who designs aeration systems on a regular basis, suggested modifying the program so it would run without a printer or commercial software. Others reiterated their previous comments to add new capabilities. The reviewers also wanted expert users to be able to change design guideline factors easily. Some Very positive comments were 1) ”good program”; 2) "it serves the audience you identify”; 3) "with use it, like old wine, will get better with age"; 4) ”generally very good and easy to use” and 5) ”very impressed". IMPLICATIONS OF EVALUATION The results of the evaluation process were scrutinized to consider the implications for future use of the aeration system design program. Following are implications for the technical content and usability of the program. TECHNICAL iMPLICATIONS The concurrent validity test indicated that a ”moderate" or "substantial" difference exists between the design guidelines used in the program and by the reviewers. Differences in design guidelines among the reviewers were also found. The results generated by the program were concurrent with the guidelines used to develop the program, so the difference in problem solutions is a function of variation in experts' preferred guidelines. Reviewers generally approved the content and sensitivity of the program. Construct Considerations Changing the program to completely satisfy all reviewers may be an enormous task. However, some key changes would make the program more 95 flexible. One change would be to allow an expert to change design guideline factors in the program. This capability should be available to experts only and not to clients. For example, an expert could customize the program by changing the air path ratio factors. Five changes are recommended for the construct of the program. The program could generate more practical designs for shallow storages by ignoring grain depths equal to or less than a given parameter. This parameter should be alterable by an aeration design expert and would initially be set at 1.2 m (4 ft). This parameter should be verified with experimental data or observations. The second recommended change is to increase the percent airflow velocity variation from 5 to 10 percent, to allow selection of a smaller size fan, duct or supply tube. The third change addresses the variation in rules used to determine the distance to offset a perforated duct from the end of a storage. The current method maintains air paths as equal as possible and should be retained as a calculation of the maximum distance to offset a duct from the end of a storage. Another method is needed which allows a greater variation in air flow paths, similar to the results of the reviewers. A ratio factor should be used to allow an aeration design expert to place the end of a duct between the points determined by the two methods. For example, if the ratio factor was set at 0.5, the end of the duct would be placed halfway between the two points. Another change is to increase the allowable length of plastic aeration tubing from a fan. The current value of 18.2 m (60 It) should be changed to 24.4 m (80 ft). The fifth change is to include additional fan size data in the program, particularly data for centrifugal fans less than 3.7 kW (5 hp). 96 Development of the aeration system design program and the technical review process pointed out several areas of aeration system design that would benefit from additional research. Some t0pics that should be considered for investigation are - the allowable depth of grain that will cool or warm by conduction without aeration -- effects of a tarp-covered storage on airflow distribution along a duct - effects of a small percentage of open area in ducts on airflow distribution - rules for determining the offset of a perforated duct from the end of a storage -— effects of corrugated and smooth wall conduits on airflow distribution - bed depth to use in estimating static pressure of grain in a flat storage Content Considerations Reviewers suggested improvements to the response screens and 'help' information as listed in Tables 17 and 19. Some suggestions are purely cosmetic. Incorporation of these changes should depend on the expert who is using the program or preparing it for use by non-experts. Two changes are recommended for the response screens. First, the question about structure liners should be clarified to state that, if requested, information will be printed at the end of the program. Second, illustrations for the fan arrangement screen should be improved. The illustration for ”fans at ends only” should be changed to have fans at only one end of the storage. The figures should be rescaled so that length and width are approximately equal or different figures should be used for widthwise and lengthwise duct direction. An expert who wants to use the program himself or have clients use it should consider making changes to the questions and 'help' information to customize 97 the program. The text displayed on the screens is defined in an ASCII file that can easily be modified with common text editing software. USABILITY IMPLICATIONS Results of the usability evaluation were very favorable. The user interface developed for this program was very easy to use and was recommended for use by beginning microcomputer users, county extension agents and farmers. Two changes are recommended for the interview processor. One, the user interface should be changed so the highlighted option on choice response screens is always selected when the screen is exited. Two, the user interface should be adapted to run on common IBM-compatible computers with graphics capabilities by adding display device independence. Reviewers offered suggestions for the design drawing, component specification list and management recommendations. The term 'connector' on the component specification list should be changed to 'supply tube'. Changes to the management recommendations should be tailored to the expert using the program. Any changes to the management recommendations can be made with text editing software since an ASCII file similar to the interview text is used. The aeration system design program should be evaluated by county extension agents and farmers for ease of use. This additional evaluation may result in further improvements to the interview processor. The development system (described in Chapter III) should be used to develop additional applications to test its flexibilities. Software tools in the development system should be updated as improved versions become available. Software improvements should make it easier to develop a new application. The cost of commercial software used in the development system is a hindrance to distribution of programs developed with the system. Lower cost 98 commercial products should be considered or advantageous licensing agreements should be pursued with the manufacturers. CHAPTER VI SUMMARY AND RECOMMENDATIONS A computer program was developed to design aeration systems for farm- sized flat grain storages. The program utilizes interactive computer graphics technology to interact with users. Aeration system design guidelines and recommendations from various sources were consolidated into a set of guidelines for use in the computer program. A development system was presented and set of software tools was synthesized for development of agricultural engineering design programs. The development system was modeled after an expert's problem solving process for design applications and divides a computer program into components of interview, calculations, design drawing and management recommendations. With this development system a computer program may be developed using several different software products, but the program appears as one to a user. A group of software tools suitable for implementing each component of the development system was presented and the tools used to implement the aeration system design program were described. The interview, management recommendations and framework components were implemented with software developed in the Interactive Computer Graphics Laboratory in the Agricultural Engineering department at Michigan State University. The calculations component consisted of a program written by the author in the 'C' programming 99 100 language. Commercial software products, AutoCAD and Synthesis, were used to implement the design drawing processor. The calculations component of the aeration system design program consists of post spacing, storage capacity and component placement and sizing modules. The placement of ducts was accomplished with a modified air path ratio method. A higher air path ratio was used to place a duct from an outer wall of a storage compared to placement in the center of a storage. This method results in duct placement similar to methods which base the number and placement of ducts on the size of the storage. Based on the user responses to questions about a grain storage, the program prepares paper copy of a floor plan of the duct layout, a list of component specifications and a list management recommendations for the user. A stnictured review process was used to evaluate the aeration system design program. Nine extension specialists and industry representatives evaluated technical and usability aspects of the program. Technical content was evaluated for concurrent validity, construct validity, content validity and sensitivity. Usability evaluation centered on ease of use, information conveyance, pertinence of illustrations and usefulness of the design drawing and management recommendations. Differences were found between results generated by the computer program and the reviewers. Differences were also found among reviewers. The difference in problem solutions is a function of variation in the reviewers' preferred guidelines. Reviewers generally approved the content and sensitivity of the program. Results of the usability evaluation wdre very favorable. The user interface was rated very easy to use and was recommended for use by beginning microcomputer users, county extension agents and farmers. Reviewers agreed 101 that the program (as is or with changes) would be helpful to them in the process of designing aeration systems. They would recommend the program to county extension agents, farmers and aeration equipment suppliers. Two-thirds of the reviewers were considering changes to their design process as a result of the evaluation process. RECOMMENDATIONS FOR AGRICULTURAL DESIGN PROGRAMS The development system described in Chapter III should be used for development of agricultural engineering design programs. By dividing the program development process into components, commercial software products can be used when available and the software used to implement one component of the program can be upgraded or replaced without redoing the entire program. Graphics should be utilized in a program as much as possible, as they stimulate a user's interest and can be used to reduce the amount of text a user must read. Software tools in the development system should be upgraded as improved versions become available. Software improvements should make it easier to develop an application. Lower cost commercial software products should be considered to make it easier for interested parties to obtain and run the program. RECOMMENDATIONS FOR AERATION SYSTEM DESIGN Development of the aeration system design program and the technical review process pointed out several areas of aeration system design that would benefit from additional research. Some topics that should be investigated are - the allowable depth of grain that will cool or warm by conduction without aeration. - the effects of a tarp-covered storage on airflow distribution along a duct. 102 the effects of a small percentage of open area in ducts on airflow distribution. the effects of corrugated and smooth wall conduits on airflow distribution. rules for determining the offset of a perforated duct from the end of a storage. the bed depth to use in estimating static pressure of grain in a peaked storage. LIST OF REFERENCES LIST OF REFERENCES ASAE. 1987. ASAE standards 1987. American Society of Agricultural Engineers. St. Joseph, Michigan. AT&T. 1985. AT&T image capture board: truevision image processing software. AT&T Electronic Photography and Imaging Center, Indianapolis, Indiana. Borg, WP. and MD. Gall. 1971. Education research an introduction. David McKay Company, New York. Brook, RC. 1979. Aeration systems for dry grain. Agricultural Engineering Information Series bulletin AElS-391, File No. 18.151. Michigan State University, E. Lansing, Michigan. Brook, RC. and E.W. Harmsen. 1982. Aeration fan and duct selection for flat grain storage. User's Manual for TELCAL 2.2. Cooperative Extension Service, Michigan State University, E. Lansing, Michigan. Brook, RC. 1983. Using buildings for grain storage. Agricultural Engineering lnforrnation Series bulletin AElS-478, File No. 18.154. Michigan State University, E. Lansing, Michigan. Brook, RC. 1986. Unpublished data on airflow tests through plastic aeration duct. Agricultural Engineering Department, Michigan State University, E. Lansing, Michigan. Brook, RC. and DC. Watson. 1986. Stored grain management. Agricultural Engineering lnforrnation Series bulletin AElS-560, File No. 18.15. Michigan State University, E. Lansing, Michigan. Brooker, D.B., F.W. Bakker-Arkema and CW. Hall, 1974. Drying cereal grains. The AVI Publishing Company, Inc. Westport, Connecticut. Burrell, N.J. 1974. Aeration. Chapter 12 in: Storage of cereal grains and their products. American Association of Cereal Chemists, St. Paul, Minnesota. 103 104 Cloud, HA. and RV. Morey. 1980. Fan and equipment selection for natural-air drying, dryeration, in-storage cooling, and aeration systems. Agricultural Extension Service bulletin M-166. University of Minnesota, St. Paul, Minnesota. Foster, G.H. and J. Tuite. 1986. Aeration and stored grain management. Chapter 5 in: Storage of cereal grains and their products. American Association of Cereal Chemists, St. Paul, Minnesota. Hancor, 1985. Hancor grain aeration system design. Hancor Engineering Facts. Hancor, Inc. Findlay, Ohio. Holligan, P.J., R. Wingate-Hall and RC. Danh. 1982. Capacities of rectangular containers filled with free floating materials. Journal of Agricultural Engineering Research 27: 363-367. Holman, LE., compiler. 1960. Aeration of grain in commercial storages. Marketing Research Report No. 178. Transportation and Facilities Research Division, Agricultural Marketing Service, United States Department of Agriculture. Hunter A.J., 1985. Formulae for the volume of stored granular materials. Journal of Agricultural Engineering Research 32:31 -46. Irish, W.W., G.D. Wells, R.A. Parsons and GR. Bodman. 1984. Pole and post buildings: design and construction handbook. Northeast Regional Agricultural Engineering Service. McKenzie, BA. 1978. Sizing aeration and storage components for grain. Paper developed forthe Farm Electrification Conference. Purdue University, W. Lafayette, Indiana. Midwest Plan Service. 1987. Grain drying, handling, and storage handbook. In press. Midwest Plan Service, Ames, Iowa. Noyes, RT. 1967. Aeration for safe grain storage. Cooperative Extension Service bulletin AE-71. Purdue University, W. Lafayette, Indiana. Peterson, W.H. 1985. Design principles for grain aeration in flat storages. Illinois Farm Electrification Council Fact Sheet No. 9. University of Illinois, Urbana, Illinois. Pierce, RC. and GR. Bodman, 1987. Piling angles of corn and milo. American Society of Agricultural Engineers paper No. 87-4058. St. Joseph, Michigan. 105 Shove, G.C. 1959. Airflow analysis of grain ventilation ducts. Unpublished PhD dissertation. Iowa State University, Ames, Iowa. Steele, J.L. and G.C. Shove. 1969. Design charts for flow and pressure distribution in perforated air ducts. Transactions of the ASAE 12(2):220-224. Watson, D.G., G.A. Peterson and W.G. Bickert. 1986. Software system for developing interactive computer graphics applications. American Society of Agricultural Engineers paper No. 86-5027. St. Joseph, Michigan. APPENDICES APPENDIX A Listing of Interview Text File i/ID INFI t/TLl AERATION SYSTEM DESIGN i/TX Developed by: 0.6. Watson and R.C. Brook Kellogg Computer Graphics Project Agricultural Engineering Michigan State University E. Lansing, MI 48824 (517) 355-1890 Copyright 1987 All Rights Reserved SIEX SIHP aerplan i/HL INFZ SINK INFSO t/ID INFIO t/TLl Help with key commands t/IX Key Function Fl Help with current screen F2 Help with key commands F3 or PgUp Back up to previous screen F4 or PgDn Continue to next screen F9 Restart from beginning Alt-F10 Quit program Use the Up and Down arrow keys to change position of the highlight box. The 'Enter' key is used to: 1) select or deselect a choice response 2) end an alphanumeric or numeric response. t/EX i/NP t/NX END t/ID INFSO t/TL General instructions t/TXPleese note the two lines in the green area at the bottom of the screen. These two lines of help information are visible at all times. Press the F1 key, a sample help screen will be displayed. Press the F2 key, a list of special key commands will be displayed. The F1 and F2 keys can be pressed at any time. 106 107 t/EX t/HP keys t/HL INFSl t/NX ALPIlO t/ID ALP110 t/TLl Client information t/ONl Enter the following information about t/ONZ the client: SIPRI name SIPRZ company S/PR3 address t/PR4 city t/PRS state t/PRS zip code S/PR7 phone t/VRl name 01.30s fi/VR2 company 01.30s slVR3 address 01.30s t/VRQ city 01.30s t/VRS state 01.30s ‘IVRS zip_code 01.30s t/VR? phone 01.30s t/HP clientin ‘IHL INF111 SINK CHOIZO t/ID CHOIZO t/TLl Grain type S/QNl Select the type of grain to be stored: t/PRI shelled corn t/PRZ soybeans SIPRB wheat t/PR4 grain sorghum QIVRI grain_type tld t/HP grains t/HL INF121 t/NX CHOl40 \IID C80140 SlTLl New structure t/QNl Is a new structure planned for the t/ONZ grain storage? 0/PR1 no t/PRZ yes fi/VRI new_building 51d SIHP structur t/HL INFldl i/NX CHOl45 CH0147 t/ID CHOI4S h/TLl Construction type ‘IQNI Is your storage structure of post-frame t/QNZ construction? t/PRl yes t/PRZ no i/VRl construction_type 51d t/HL INF146 fi/NX CHOISO CH0160 t/ID CH0147 SITLl Construction type t/ONl Are you planning to use post-frame t/ONZ construction for your new building? t/PRl yes SIPRZ no i/VRl construction_type 51d t/HL INF148 ‘INX CHOISO CH0160 t/ID CH0150 SITLl Post spacing SIONI i/ONZ ‘IONJ SIPRI 9/PR2 9/PR3 9/PR4 9/PR5 \lVRl 108 Select the post spacing of the storage structure or self supporting grain wall: 2 feet 4 feet 6 feet 8 feet self supporting grain wall post_spacing 91d QIHP postspac ‘IHL INFISl t/NX CHOléo i/ID CHOIGO 9/TL1 ‘IQNI 9/ON2 9/PR1 t/PRZ 9/VRI SIB? Structure liner Do you need information on grain liners or self supporting grain walls? no yes liner_info 51d liners 9/HL INF161 QINX NUM170 S/ID NUM170 ‘ITLI ‘IONI ‘IPRI SIPRZ QIVRI .lVRZ Storage size Enter the length and width of the storage: storage width, ft storage length, ft storage_width 05.1f 40 1 999 storage_length 95.1f 80 1 999 ‘IHP storsize ‘IHL INF171 SINX NUM180 9/ID NUM180 9/TL1 SIONI ‘IONZ i/PRI 9/PR2 9/PR3 9/PR4 9/VR1 ‘IVRZ 9/VR3 9/VR4 Grain depths on walls Enter the higher and lower grain depths planned for the side and end walls: higher side grain depth, ft lower side grain depth, ft higher end grain depth, ft lower and grain depth, ft higher_sidewall_height 95.2f 4 0 30 lower_sidewall_height 95.2f 4 0 30 higher_endwall_height 95.2f 4 0 30 lower_endwall_height 95.2f 4 0 30 9/HP walldpth SIHL INF181 SINX SPL filID NUM180b 9/TL1 9/081 SIONZ fi/PRI SIPRZ SIPR3 i/PR4 Grain depths on walls Enter the deep and shallow grain depths planned for the side and end walls: deep side grain depth, ft shallow side grain depth, ft deep and grain depth, ft shallow and grain depth, ft 9/VR1 higher_sidewall_height 15.2f 4 0 20 t/VRZ lower_sidewall_height 35.2f 4 0 20 t/VR3 higher_endwall_height 95.2f 4 0 20 §IVR4 lower_endwall_height 95.2! 4 0 20 t/HP walldpth t/HL INF181 i/NX SPL fi/ID INF185 9/TL1 Post size SIIXBased on the 9/post_spac_ft ft post spacing and the highest grain depth of t/highest_wall ft, a post size of at least t/pcst_size is required. 109 SIEX ‘IHP postsize t/HL INF186 t/NX NUM190 8/ID INF187 9/TL1 Post size t/TXNARNING: Based on the post spacing of t/post_spac_ft ft and the highest grain depth on a wall of 9/highest_wall ft a post size of greater than 8' x 8' is required. I/Ex tt/HL INF188 SINX NUM190 9/ID NUM190 t/TLl Maximum piling height SIONI Enter the maximum piling height of the 9/0N2 grain in the storage structure: 8/PR1 maximum piling height, ft 9/VRl maximum_piling_height 95.2f 12 1 99 9/HP maxpile ’IHL INF191 9/NX SPL 9/ID INF193 SITLl Grain depth problem SITXGrain depths on walls are impossible based on storage dimensions. Either the storage is very small or a grain depth on a wall is very high. Check your storage dimensions. If they are correct, the grain depths on the walls must be reduced. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate the program. SIEX SINX END t/ID INF195 9/TL1 Bushel capacity SITXThe grain storage you have described will hold approximately 9/bushel_capacity bushels, with the actual peak at t/peak_height ft being leveled to a width of t/width_of_peak_height ft. If this is more or less than required you may want to go back and change the storage size or grain depths. Press F3 or PgUp if you need to go back and make changes. t/EX S/HP bushel SINX CH0200 9/ID INF197 SITLI Small storage t/TXNOTE: Your grain storage of 9/bushel_capacity bushels with a peak depth of 9/peak_height ft is too small to be used with this program. Typically storages of less than t/minimum_bushels bushels or peak grain depth of 9/minimum_depth ft or less can be held for 3 months without aeration. You may want to recheck the dimensions or grain depths. 110 Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. \IEX SINX END 8/ID CH0200 SITLl Number of ducts 9/0N1 Select the method for determining the SIONZ number of ducts: 9/PR1 computer selected 8/PR2 user selected SIVRl duct_selection_method 81d ‘18? compman t/HL INFZOl SINX SPL t/ID NUMZOS 8/TL1 Number of ducts SIQNI Enter the number of ducts to place in SIONZ the storage: SIPRl number of ducts 8/VR1 desired_number_of_ducts 81d SIHP numducts 9/HL INF206 S/NX CH0240 9/ID CHOZ40 9/TL1 Duct type 0/ON1 Select the preferred duct type: QIPRI plastic SIPRZ spiral-10k metal 8/233 round metal t/PR4 half-round metal 9/VR1 duct_type 91d 9/HP ducttype 8/HL INF241 QINX CHOZJO 9/ID CHOZJO SITLl Duct direction 8/0Nl Select the preferred direction of 9/ON2 duct runs: SIPRI lengthwise 9/PR2 widthwise 9/VR1 duct_direction 91d 9/HF ductdirc S/HL INF231 SINX CHOZZO t/ID CHOZZO 9/TL1 Fan type 9/QN1 Select the type of fan you prefer to use: ilPRl axial 9/PR2 centrifugal ‘IVRI fan_type 91d SIHP fantype ilHL INF221 SINX CH0210 i/ID CH0210 SITLl Fan arrangement SIQNl Select a fan arrangement option: 9/PR1 end and middle placement 9/PR2 and placement only 9/PR3 middle placement preferred 8/VR1 desired_fan_arrangement 51d OIHP fanarr i/HL INF211 SINX NUMZSO ‘IID NUMZSO 111 S/TLl Airflow rate S/QNl Enter the design airflow rate for the S/QNZ aeration system in terms of cfm per S/QN3 bushel: S/PRl airflow rate, cfm/bu S/VRl cfm_per_bushel S4.2f 0.15 0.01 9.99 S/HP airflow S/HL INFZSI S/NK SPL S/ID INF261 S/TLl Calculations complete S/TK This grain storage requires S/number_of_ducts duct(s). This program will next print the component specifications and display the aeration system plan. Be sure the printer is ready before continuing. S/EK SINK SPL S/ID INF263 S/TLl Too many ducts S/TKThis grain storage requires more than 20 ducts, which is the limit for this program. Either the storage is very large or the grain profile is very shallow. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. S/EK S/NK INF300 S/ID INF265 S/TLl Nidthwise placement not recommended S/TKNidthwise duct placement is not recommended for this storage. The resulting airflow would be too non-uniform. Try placing ducts lengthwise or changing grain depths to provide a more level grain profile. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. S/EK S/NK INF300 S/ID INF267 S/TLl Lengthwise placement not recommended S/TKLengthwise duct placement is not recommended for this storage. The resulting airflow would be too non-uniform. Try changing grain depths to provide a more level grain profile. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. S/EK S/NK INF300 S/ID INF269 S/TLl More than 2 fans per duct S/TKMore than 2 fans are required for a duct, which is the limit for this program. , Try shortening the storage dimension corresponding to the direction of duct runs 112 or change the duct direction. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. SIEK SINK INFBOO SIID INF271 S/TLl Fan size not available S/TKA fan size required for the storage is larger than the maximum available size. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. S/EK SINK INF300 SIID INF273 SITLl Duct size not available SITKA duct size required for the storage is larger than the maximum available size. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. S/EK SINK INF300 SIID INF275 S/TLl Connector size not available SITKA connector size required for the storage is larger than the maximum available size. Use F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. S/EK SINK INF300 SIID INF277 SITLl Calculations complete SITK You selected SIdesired_number_of_ducts duct(s) and the program designed for S/number_of_ducts duct(s). This program will next print the component specifications and display the aeration system plan. Be sure the printer is ready before continuing. S/BK SINK SPL SIID INF278 S/TLl Calculations complete S/TKYou selected SIdesired_number_of_ducts duct(s) and the program designed for SInumber_of_ducts duct(s). NARNING: This arrangement is not recommended. The air path ratio from the outermost duct to the wall is SImax_apr which exceeds the normal maximum of SIdesign_max_apr for this situation. You should back up and increase the number of ducts or let this program select the number of ducts. S/EK SINK INF279 113 SIID INF279 - SITLl Calculations complete SITK Should you continue and use this design, be advised that the risk of grain spoilage is very high. This program will next print the component specifications and display the aeration system plan. Be sure the printer is ready before continuing. SIEK SINK SPL SIID CHOZBO SITLl Recommendations S/QNl Are you satisfied with the design? SIQNZ (If so. the recommendations will be S/ON3 printed.) SIPRI yes S/PRZ no S/VRl recommendations Sld SIHL SINK SPL INF290 SIID INF290 SITLl Unfinished design S/TX You can use the F3 or PgUp keys to go back and change your responses or continue forward to terminate this program. SIEK SINK INF300 SIID INF300 SITLl End of program SITK Thank you for using this aeration system design program. Remember to take your printouts. Pressing F4 or PgDn on this screen will end this program. S/EX SINK END SIID INF2 S/TLl Help for aeration system design SITKThe aeration system design program generates a customized aeration system plan based on the information provided by the user. This program was developed for farm-size flat grain storages. S/EK SIHP aerplan SINK END SIID INFSl SITLl Help for general instructions S/TKThis is a sample help screen. If you press the F1 key when a question is displayed on a screen, a help screen like this will contain information about the question. SIEK 114 S/HP keys SINK END SIID INFlll SITLl Help for client information SITKThe client is the person for whom the aeration system is being designed. Information about the client is requested for future reference in contacting the client and printing name and address on printouts. Company name may be a farm name or left blank. S/EK S/HP clientin SINK END SIID INF121 SITLl Help for grain type SITKThe aeration system design program will design an aeration system for 4 crops: shelled corn, soybeans, wheat and grain sorghum. The type of grain determines the angle of repose or filling angle of the grain in storage and the performance of an aeration system. Small grains such as wheat and grain sorghum offer higher static pressure and result in lower airflow from a given aeration fan. SIBK SIHP grains SINK END SIID INF141 SITLl Help for new structure S/TKThis response is used to make an appropriate management recommendation. If an existing structure is to be used for grain storage, a vapor barrier will probably be needed on the floor. Also, a metal roof invariably leaks somewhere and will need to be patched. If a new structure is to be built, a vapor barrier should be placed on the ground before pouring the concrete floor. Also consider a shingled roof to eliminate water leakage. SIEK SIHP structure SINK END SIID INF146 S/TLl Help for construction type SITKIf your storage structure is post-frame construction, you will be asked about post spacing and the required post size will be calculated. If your structure is not post-frame construction and you plan to pile grain against the walls, you should contact the manufacturer, builder or a consulting engineer to verify that the structure will support the desired depth of grain on the 115 side walls. SIEK SINK END SIID INF148 S/TLl Help for construction type S/TKIf your storage structure will be post-frame construction, you will be asked about post spacing. You can enter a planned post spacing and the required post size will be calculated for you. If your structure will not be post-frame construction and you plan to pile grain against the walls, you should consult with potential builders about the suitability of the building to support grain on the side walls. SIEK SINK END SIID INF151 SITLl Help for post spacing SITKThis response is used to calculate the required post size for the building. A self supporting grain wall may be used to eliminate having to reinforce the building wall. If this is the case select the 'self supporting grain wall' option. Post spacing often limits the depth to which grain can be piled on the building walls. Grain piled too high on a side wall may result in structural damage. SIEK SIHP postspac SINK END SIID INFlél SITLl Help for structure liner SITKBy responding yes to this question, a source of plans for grain liners and self supporting grain walls will be included in the recommendations printed later in the program. A liner must be installed in the storage structure to withstand the force of the grain on the walls. Various types of liners are available. Two common ones are plywood liners and self supporting grain walls. SIEK SIHP liners SINK END SIID INF171 S/TLl Help for storage size SITKThe storage size is used to calculate the bushel capacity of the storage and determine the placement of ducts. If you are not sure how much space in a building will be needed for grain storage, you can start with a trial width and length. The actual capacity will be calculated and you can revise the storage dimensions. SIEK SIHP storsize SINK END 116 SIID INF181 S/TLl Help for grain depth on walls S/TKGrain depths are used to calculate the storage size and determine the placement of ducts. This program will work with different grain depths on the four walls. Consider the side walls separately from the end walls. The side walls are the longer walls in the storage. If the two side (or end) walls will be at different grain depths then enter the higher of the two depths as the higher side (or end) grain depth. SIEK S/HP walldpth SINK END SIID INF186 S/TLl Help for post size SITKThe post size was calculated based on the post spacing and the highest grain depth on a wall. If a post smaller than S/post_size is used, then structural damage may occur. If your posts are smaller than S/post_size consider reducing grain depths on the walls or using a self supporting grain wall. SIEK SIHP postsize SINK END SIID INF188 S/TLl Help for post size SITKThis program attempted to determine the required post size based on the post spacing and the highest grain depth on a wall. The largest post size for which information is available is 8' x 8'. Consider reducing the grain depths on the walls or using a self supporting grain wall. SIEK SINK END SIID INF191 SITLl Help for maximum piling height S/TKMaximum piling height is used to determine the bushel capacity of the storage and size aeration equipment. ' Maximum piling height is the limit for how high the grain can be piled in the storage. A common limitation is the height of the trusses, since grain should not be piled up into the trusses. Loading equipment may further limit the piling height of the grain. SIEK SIHP maxpile SINK END SIID INFZOI 117 SITLl Help for number of ducts SITKThis program can determine the number of ducts to aerate the grain properly or you can set the number of ducts. It is advised that the 'computer selected' option be selected. SIEK S/HP compman SINK END SIID INF206 SITLl Help for number of ducts SITKYou have elected to enter the number of ducts to be placed in the storage. If you would rather have this program determine the number of ducts, use F3 or PgUp to back up to the previous screen and choose the 'computer selected' option. If the program has previously indicated that the required fan or duct size was larger than available, then you may need to increment the number of ducts determined by this program until the fan and duct sizes match available sizes. SIEK S/HP numducts SINK END SIID INFle SITLl Help for fan arrangement SITKThis response is used to determine whether to place a fan at the end or middle of a duct. In long storages (100' or more) the number of fans required can be reduced by placing 1 fan in the middle of the outermost ducts instead of 1 fan at each end. For long duct lengths the option 'end and middle placement' allows the program to select the placement with the least fans. The choice 'middle placement preferred' will place fans in the middle of the outermost ducts regardless of duct length. SIEK S/HP fanarr SINK END SIID INF221 S/TLl Help for fan type SITKA fan size will be determined for the fan type you select. An axial fan is usually chosen for flat storages. The smallest centrifugal fan (27'-5hp) is too large in most cases and a matching duct size is not available. Centrifugal fans are required if static pressures exceed 4' of water (which is rarely the case in flat storages) or noise level limits require a centrifugal fan. In either case, 1 fan may need to supply multiple ducts and this program does not allow a fan to supply more than 1 duct. SIEK S/HP fantype SINK END SIID INF231 SITLl Help for duct direction 118 S/TKDucts should be placed in the storage in the direction which will result in the most uniform grain depth over the duct. In most cases this means lengthwise placement. In some storages, widthwise placement is not recommended because the variation in grain depth will severely reduce the performance of the aeration system. SIEK SIHP ductdirc SINK END SIID INF241 SITLl Help for duct type SITKThe duct type affects the cost of an aeration system. Any of the ducts types will do an acceptable job in distributing air through the grain. Plastic ducts are often desirable due to lower costs, but are more susceptible to damage during handling. Spiral-lok metal is usually less expensive than round metal. The design difference between plastic and other round ducts is the allowable length of a duct. Plastic ducts are limited to shorter runs. SIEK S/HP ducttype SINK END SIID INF251 SITLl Help for airflow rate SITKThe airflow rate is a factor in sizing a fan. A proper airflow rate should be selected for grain aeration. An airflow of 0.1 to 0.2 cfm (cubic feet/ minute) per bushel is needed for farm stored grains. An airflow of 0.1 cfm/bu is adequate for clean, dry grain. For poor quality grain (high broken kernels and fines content) use 0.2 cfm/bu for an adequate airflow. For grain of average condition an airflow rate of 0.15 cfm/bu is recommended. SIEK SIHP airflow SINK END SIID “25170 SITKThe length of the storage must be greater than or equal to its width. Press a key to continue. SIEK SIID MESIBOA SITKGrain depth on the higher side wall must be greater than or equal to the lower side wall depth. Press a key to continue. SIEK S/ID MESlBOB SITKGrain depth on the higher end wall must be greater than or equal to the lower end wall depth. 119 Press a key to continue. SIEK SIID M35190 S/TKGrain depth on the walls of the storage cannot be higher than the maximum piling height. Press a key to continue. SIEK SIID M35250 SITKOne moment please, while the necessary calculations are performed. SIEK SIID M35261 SITKOne moment please, while the component specifications are being printed and the drawing is being prepared for display. SIEK SIID M25280 SITKOne moment please, while the recommendations are being prepared and printed. SIEK SIID MESAlOl S/TKUnable to open file to write data structure. SIEK SIID MESAlOZ S/TKUnable to close file after writing data structure. SIEK SIID MESAIOJ S/TKUnable to open file to read data into structure. SIEK SIID MESAIOS S/TKUnable to close file after reading data into structure. SIEK SIID MESAlOS SITKUnable to Open file to write data items. SIEK SIID MESAlOS SITKUnable to close file after writing data items. SIEK * SIID MESAlO? SITKUnable to open file to read data items into structure. SIEK SIID MESAIOH SITKUnable to close file after reading data items into structure. S/EX SIID MESAIO9 SITKUnable to open drawing specification file. S/EX 120 SIID MESAllO SITKUnable to close drawing specification file. S/EX SIID MESAlll SITKUnable to open component specification file. SIEK SIID MESAllZ SITKUnable to close component specification file. SIEK APPENDIX B 'C' Source Code for Function to Perform Consistency Checks int consistency_check(key) char I'key: ( I' consistency_check *I double x, y, z: char value_string[MAK_STRING_LENGTH]: if (!strnicmp(key, I'NUMl'IO", 6)) ( get_intview_data_item('storage_width', value_string): x - atof(value_string): get_intview_data_item('storage_length', value_string): y - atof(value_string): if (y < x) { display_message('MESI70', TIL_KBHIT): return ('1): } else if (!strnicmp(key, 'NUMlBO', 6)) { get_intview_data_item('higher_sidewall_height', value_string): x - atof(value_string): get_intview_data_item('lower_sidewall_height', value_string); y - atof(value_string): if (x < y) I display_message('MESIBOa', TIL_KBHIT): return (-l): } get_intview_data_item('higher_endwall_height', value_string): x - atof(value_string): get_intview_data_item('lower_endwall_height', value_string): y - atof(value_string): if (x < y) { display_message('MESIHOb', TIL_KBHIT): return (-l): } } else if (3strnicmp(key, 'NUM190', 6)) { get_intview_data_item('higher_sidewall_height', value_string): x - atof(value_string); get_intview_data_item('higher_endwall_height', value_string); y - atof(value_string): get_intview_data_item('maximum_piling_height', value_string); z - atof(value_string); if (z < max(x, y)) { display_message('MESl90', TIL_KBHIT): return (-1): } } return (0): } /* consistency_check 'I 121 APPENDIX C 'C' Source Code for Function to Perform Special Flow Control void special_next_screen(key) char 'key: { /‘ special_next_screen */ char temp_string[MAK_STRING_LENGTH]: if (istrnicmp(key, 'NUMlBO', 6)) ( } copy_data_to_struct(): if (design_data.post_spacing it larger(design_data.higher_sidewall_height, { i { } design_data.higher_endwall_height) > 0) if (post_sizing()) strcpy(screen_key, 'INF187'); else { sprintf(temp_string, 'Sd', design_data.post_spacing); put_intview_data_item('post_spac_ft', temp_string): put_intview_data_item('post_size', design_data.post_size): sprintf(temp_string, I'S3.lf", larger(design_data.higher_sidewall_height, design_data.higher_endwall_height)i: put_intview_data_item('highest_wall', temp_string): strcpy(screen_key, 'INFlBS'): } else put_intview_data_item('post_size', design_data.post_size); strcpy(screen_key, 'NUMl90'); else if (istrnicmp(key, 'NUM190', 6)) i { (28.3. copy_data_to_struct(): switch (storage_capacity()) case 0: sprintf(temp_string, 'Sld', (long) design_data.bushel_capacity): put_intview_data_item('bushel_capacity', temp_string): sprintf(temp_string, 'S3.lf', design_data.peak_height): put_intview_data_item('peak_height', temp_string): sprintf(temp_string, I'S3.1f", design_data.width_of_peak_height): put_intview_data_item('width_of_peak_height', temp_string): strcpy(screen_key, 'INF195'); break: case 1: strepy(screen_key, 'INF193'): break: 2: sprintf(temp_string, 'S3.lf', design_data.peak_height): put_intview_data_item('peak_height', temp_string): sprintf(temp_string, 'Sld', (long) design_data.bushel_capacity): 122 123 put_intview_data_item('bushel_capacity', temp_string): sprintf(temp_string, 'Sd', (int) factor.minimum_bushels); put_intview_data_item('minimum_bushels', temp_string): sprintf(temp_string, 'Sd', (int) factor.minimum_depth): put_intview_data_item('minimum_depth', temp_string): strcpy(screen_key, 'INF197'); break: } } else if (!strnicmp(key, 'CHOZOO', 6)) { get_intview_data_item('duct_selection_method', temp_string): if (atoi(temp_string) -- 0) ( sprintf(temp_string, '0'): put_intview_data_item('desired_number_of_ducts', temp_string): strcpy(screen_key, 'CH0240'): } else strcpy(screen_key, 'NUMZOS'): } else if (istrnicmp(key, I'NUMZSO", 6)) ( display_message('MESZSO', LEAVE_UP): copy_data_to_struct(): switch (component_placement_sizing()) ( case 0: sprintf(temp_string, 'Sd', design_data.number_of_ducts); put_intview_data-item('number_of_ducts', temp_string); if (design_data.desired_number_of_ducts) { float higher_wall, design_apr: if (design_data.duct_direction -- LENGTHWISE) higher_wall - design_data.higher_sidewall_height: else higher_wall - design_data.higher_endwall_height: if (higher_wall >- factor.depth_deep) design_apr - factor.ratio_deep: else design_apr - factor.ratio_shallow: if (max(design_data.lower_side_air_path_ratio, design_data.higher_side_air_path_ratio) > design_apr) { sprintf(temp_string, 'S3.2f', max(design_data. lower_side_airdpath_ratio, design_data. higher_side_air_path_ratioii: put_intview_data_item('max_apr', temp_string): sprintf(temp_string, 'S3.1f', design_apr): put_intview_data_item('design_max_apr', temp_string): strcpy(screen_key, 'INF278'): ) else strcpy(screen_key, 'INF277'): 1 else strcpy(screen_key, 'INF261'): break: case 1: strcpy(screen_key, 'INF263'): break: case 2: strcpy(screen-key, ”INFZGS'): break: case 3: strcpy(screen_key, 'INF267'): break: case 4: strcpy(screen_key, 'INF269'): break; case 5: 124 strcpy(screen_key, 'INF271'): break: case 6: strcpy(screen_key, I'INF273"): break: case 7: strcpy(screen_key, 'INF275'); break: } flush_keyboard(): } else if (istrnicmp(key, 'INF261', 6) ll istrnicmp(key, 'INF277', 6) ll istrnicmp(key, 'INF279', 6)) { display_message('MESZ61', LEAVE_UP): drawing_processor(): strcpy(screen_key, 'CH0280'): flush_keyboard(): } else if (istrnicmp(key, 'CHOZBO', 6)) { get_intview_data_item('recommendations', temp_string); if (atoi(temp_string) -- 0) ( display_message('MESZBO', LEAVE_UP): recommendations_processor(): } strcpy(screen_key, 'INF300'); flush_keyboard(): /* special_next_screen */ APPENDIX D Sample Data File Produced by interview Component name company address city state zip_code phone grain_type new_building construction_type post_spacing liner_info storage_width storage_length higher_sidewall_height lower_sidewall_height higher_endwall_height lower_endwall_height post_spac_ft post_size highest_wall maximum_piling_height bushel_capacity peak_height width_of_peak_height duct_selection_method desired_number_of_ducts duct_type duct_direction fan_type desired_fan_arrangement cfm_per_bushel Dennis Watson Michigan State University 106A Farrall Hall E. Lansing Michigan 48824 123-456-7890 0 O OO‘OSCSGHUSOUO OO O Ham m- s O X as x 54517 16.0 17.1 OOOONO O APPENDIX E Sample Data File Produced by Calculations Component name company address city state zip_code phone grain_type new_building construction_type post_spacing liner_info storage_width storage_length higher_sidewall_height lower_sidewall_height higher_endwall_height lower_endwall_height maximum_piling_height desired_number_of_ducts desired_fan_arrangement fan_type duct_direction duct_type cfm_per_bushel post_size tan_angle_of_repose peak_height width_of_peak_height 1ength_of_peak_height bushel_capacity lower_side_air_path_ratio higher_side_air_path_ratio number_of_ducts duct_diameter duct_length duct_distance_from_lower_sidewall duct_distance_from_lower_endwall duct_distance_to_lower_boundary duct_distance_to_higher_boundary duct_bushels duct_fan_arrangement number_of_fans fan_diameter fan_horsepower fan_cfm fan_operating_static_pressure connector_diameter connector_length connector_distance_from_lower_sidewall connector_distance_from_lower_endwall duct_diameter duct_length duct_distance_from_lower_sidewall Dennis Watson Michigan State University 106A Farrall Hall E. Lansing Michigan 48824 123-456-7890 0 0 0 8 0 60.000000 100.000000 6.000000 6.000000 6.000000 6.000000 16.000000 0 NOOO 0.150000 6' x 6' 0.466308 16.000000 17.109862 57.109862 54517.499342 1.639740 1.639740 4 12 81.000000 9.500000 9.500000 0.000000 12.000000 8270.757177 0 1 12 0.330000 1740.190226 0.596495 14 9.000000 0.000000 50.000000 21 53.500000 23.250000 duct_distance_from_lower_endwall duct-distance_to_lower_boundary duct_distance_to_higher_boundary duct_bushels duct_fan_arrangement number_of_fans fan_diameter fan_horsepower fan_cfm fan_operating_static_pressure connector_diameter connector_length connector_distance_from_lower_sidewall connector_distance_from_lower_endwall duct_diameter duct_length duct_distance_from_lower_sidewall duct_distance_from_lower_endwall duct_distance_to_lower_boundary duct_distance_to_higher_boundary duct_bushels duct_fan_arrangement number_of_fans fan_diameter fan_horsepower fan_cfm fan_operating_static_pressure connector_diameter connector_length connector_distance_from_lower_sidewall connector_distance_from_lower_endwall duct_diameter duct_length duct_distance_from_lower_sidewall duct_distance_from_lower_endwall duct_distance_to_lower_boundary duct_distance_to_higher_boundary duct_bushels duct_fan_arrangement number_of_fans fan_diameter fan_horsepower fan_cfm fan_operating_static_pressure connector_diameter connector_length connector_distance_from_lower_sidewall connector_distance_from_lower_endwall 23.250000 12.000000 30.000000 18987.992494 1 1 16 1.500000 3773.250000 0.5 21 23.250000 23.250000 0.000000 21 53.500000 36.750000 23.250000 30.000000 48.000000 18987.992494 1 1 16 1.500000 3773.250000 0.5 21 23.250000 36.750000 0.000000 12 81.000000 50.500000 9.500000 48.000000 60.000000 8270.757177 0 1 12 0.330000 1740.190226 0.596495 14 9.000000 60.000000 50.000000 APPENDIX F 'C' Source Code for Function to Write Specification File for Synthesis int write_drawing_spec_file(filename) char filename[]: { I' write_drawing_spec_file '/ FILE *spec_fp: double “distance_end, “distance_side, length, lower_dim_offset: double dim_x, dim_y, fan_length: int midd1e_duct, duct_number, rotation_angle: char duct_filename[9], fan_filename[9], dim_filename[9], text_filename[9]: char 'dectoarch(), ftinl30]; middle_duct - design_data.number_of_ducts / 2 - 1: if (design_data.number_of_ducts S 2) ++middle_duct: if ((spec_fp - fopen(filename, 'w')) -- NULL) { printf('\nERROR 109: Unable to open drawing specification file Ss.', filename): display_message('MESAlO9', TIL_KBHIT): return (1): I fprintf(spec_fp, 'IAERATION DESIGN DRAWING SPECIFICATION FILE\n'): fprintf(spec_fp, 'Ifor Ss.\n', design_data.name): fprintf(spec_fp, 'INUM VALUE DIMENSION TEKT\n'): fprintf(spec_fp, egsss @eeeeeeee esseeaeeaeensesesawaawanseawen\nw); fprintf(spec_fp, I'/-~-- --------- \n'); strcpy(ftin, dectoarch(design_data.storage_width)): fprintf(spec_fp, '810 S-9.2f Ss\n', design_data.storage_width, ftin): strcpy(ftin, dectoarch(design_data.storage_length)); fprintf(spec_fp, I'.$20 S-9.2f Ss\n', design_data.storage_length, ftin): fprintf(spec_fp, '\n/OUTFILE INFILE ORIGIN SCALE K Y ROTATION\n'): fprintf(spec_fp, 'ICLIENT AERBASE 0.0 0.0 1.0 1.0 0.0\n'): if (design_data.duct_direction -- LENGTHNISE) { distance_end - adesign_data.duct_distance_from_lower_endwall[0]; distance_side - £design_data.duct_distance_from_lower_sidewall[0]: length - design_data.storage_width: strepy(duct_filename, LENGTHNISE_DUCT_FILENAME): else distance_end - £design_data.duct_distance_from_lower_sidewall[0]: distance_side - £design_data.duct_distance_from_lower_endwall[0]: length - design_data.storage_length: strcpy(duct_filename, WIDTHWISE_DUCT_FILENAME): for (duct_number - 0: duct_number < design_data.number_of_ducts: ++duct_number) rotation_angle - 0: fprintf(spec_fp, '5200 S-9.2f Duct Sd\n', 1.0, duct_number + 1): fprintf(spec_fp, I$212 S-9.2f\n', (float) design_data.duct_diameter [duct_number] I FEET_INCH / 2): 128 129 fprintf(spec-fp, I$220 strcpy(ftin, dectoarch(‘(distance_end + duct_number))): fprintf(spec_fp, '5240 if (duct_number <- middle_duct) { strcpy(ftin, dectoarch(*(distance_side + duct_number))): fprintf(spec_fp, '5232 ftin): fprintf(spec_fp, “$235 S-9.2f\n', 0.005): if (design_data.duct_fan_arrangement[duct_number] > 0) fprintf(spec_fp, '5236 else fprintf(spec_fp, "$236 fprintf(spec_fp, "$237 fprintf(spec_fp, ”$238 DIM_LINE_LENGTH) ) .- S-9.2f\n', DIM_0FFSET): S-9.2f\n', DIM_OFFSET): S-9.2f\n', (float) ((duct_number + 1) ' I else I strcpy(ftin, dectoarch(length - “(distance_side + duct_number))): fprintf(spec_fp, “$232 S-9.2f duct_number), ftin): fprintf(spec_fp, I$235 duct_number)): fprintf(spec_fp, “$236 S-9.2f\n', DIM_OFFSET): if (design_data.duct_fan_arrangement[duct_number] > 0) S-9.2f\n', length - *(distance_side + lower_dim_offset - (float) design_data.fan_diameter[duct_number][0] FEET_INCH ‘ FAN_LENGTH_FACTOR + DIM_OFFSET: else lower_dim_offset - DIM_OFFSET: fprintf(spec_fp, "$237 S-9.2f\n', lower_dim_offset): fprintf(spec_fp, '3238 I if (design_data.duct_direction -- LENGTHWISE) fprintf(spec_fp, "OCLIENT Ss S9.2f S9.2f 1.0 1.0 S3d\n', duct_filename, *(distance_end + duct_number), “(distance_side + duct_number), rotation_angle): else fprintf(spec_fp, 'OCLIENT Ss S9.2f S9.2f 1.0 1.0 S3d\n', S-9.2f\n', design_data.duct_length[duct_number]): S-9.2f Ss\n', *(distance_end + duct_number), Ss\n', length - *(distance_side + ftin) a' S-9.2f Ss\n', *(distance_side + duct_number), S-9.2f\n', (float) design_data.fan_diameter [duct_number)[0] I FEET_INCH ' FAN_LENGTH_FACTOR + DIM_OFFSET): / S-9.2f\n', (float) ((design_data.number_of_ducts - duct_number) ' DIM_LINE_LENGTH + DIM_OFFSET - lower_dim_offset)): duct_filename, duct_number). fprintf(spec_fp, "$312 [duct_number][0] I fprintf(spec_fp, I'5314 [duct_number][0] I fprintf(spec_fp, "$322 [duct-number][0) I fprintf(spec_fp, '5330 [duct_number][0)): fprintf(spec_fp, "$332 '(distance_side + duct_number), *(distance_end + rotation_angle): S-9.2f\n', (float) design_data.fan_diameter FEET_INCH / 2): S-9.2f\n', (float) design_data.fan_diameter FEET_INCH ' FAN_LENGTH_FACTOR): S-9.2f\n', (float) design_data.connector_diameter FEET_INCH I 2): S-9.2f\n', design_data.connector_length S-9.2f\n', design_data.duct_length[duct_number]): if (design_data.duct_fan_arrangement[duct_number] -- 2) { S-9.2f Ss\n', 1.0, 'A'): S-9.2f Ss\n', 1.0, '8'): fprintf(spec_fp, "$300 fprintf(spec_fp, '$301 fprintf(spec_fp, '5317 [duct_number][l] I FEET_INCH / 2): fprintf(spec_fp, “$319 [duct_number][l] I FEET_INCH ' FAN_LENGTH_FACTOR): fprintf(spec_fp, '5327 [duct_number][l] / FEET_INCH I 2): fprintf(spec_fp, I$335 [duct_number][l]): fprintf(spec_fp, "$340 S-9.2f\n', 0.0): I S-9.2f\n', (float) design_data.fan_diameter S-9.2f\n', (float) design_data.fan_diameter S-9.2f\n', design_data.connector_length S-9.2f\n', (float) design_data.connector_diameter else { if (design_data.duct_fan_arrangement[duct_number] -- 1 II duct_number -- 0) fprintf(spec_fp, "$300 S-9.2f Ss\n', 1.0, 'A'): else fprintf(spec_fp, '5300 S—9.2f Ss\n', 1.0, ' ”): 130 fprintf(spec_fp, '5301 S-9.2f Ss\n', 1.0, ' '): fprintf(spec_fp, I'5317 S-9.2f\n', 0.0): fprintf(spec_fp, '3319 S-9.2f\n', 0.0): fprintf(spec_fp, '3327 S-9.2f\n', 0.0): fprintf(spec_fp, I'$33S S-9.2f\n', 0.0): I if (design_data.duct_direction -- LENGTHWISE) if (design_data.duct_fan_arrangement[duct_number]) strcpy(fan_filename, LENGTHNISE_FAN_FILENAME): else I strcpy(fan_filename, NIDTHWISE_FAN_FILENAME): if (duct_number) rotation_angle - 180: I else if (design_data.duct_fan_arrangement[duct_number]) strcpy(fan_filename, WIDTHWISE_FAN_FILENAME): else I strcpy(fan_filename, LENGTHNISE_FAN_FILENAME): if (duct_number) rotation_angle - 180: I fprintf(spec_fp, 'ICLIENT Ss S9.2f S9.2f 1.0 1.0 S3d\n', fan_filename, design_data.connector_distance_from-lower_endwall[duct_number][0], design_data.connector_distance_from_lower_sidewall[duct_number][0], rotation_angle): if (design_data.duct_fan_arrangement[duct_number] -- 0) I if (duct_number) I fprintf(spec_fp, ”$500 S-9.2f Ss\n', 1.0, 'A'): fprintf(spec_fp, "$510 S-9.2f\n', (float) design_data.fan_diameter [duct_number][O] I FEET_INCH I 2): if (design_data.duct_direction -- LENGTHWISE) strcpy(text_filename, VERTICAL_TEKT_FILENAME): else strcpy(text_filename, HORIZONTAL_TEKT_FILENAME): rotation_angle - 0: fprintf(spec_fp, 'OCLIENT Ss S9.2f S9.2f 1.0 1.0 S3d\n', text_filename, design_data.connector_distance_from_lower_endwall [duct_number][0], design_data.connector_distance_from_lower_sidewall [duct_number][0], rotation_angle): I dim_x - design_data.connector_distance_from_1ower_endwall[duct_number][0]: dim_y - design_data.connector_distance_from_lower_sidewall[duct_number][0]: fan_length - design_data.fan_diameter[duct_number][O] I FEET_INCH * FAN_LENGTH_FACTOR: fprintf(spec_fp, I'5410 S-9.2f\n', fan_length + DIM_OFFSET): fprintf(spec_fp, "$420 S-9.2f\n', 6.0 - (fan_length + DIM_OFFSET)): fprintf(spec_fp, '5430 S-9.2f\n', DIM_OFFSET): if (design_data.duct_direction -- LENGTHWISE) I strcpy(ftin, dectoarch(dim_x)): fprintf(spec_fp, "$440 S-9.21f Ss\n', dim_x, ftin): if (duct_number) strcpy(dim_filename, HORIZONTAL_DIM1_FILENAME): else strcpy(dim_filename, HORIZONTAL_DIMO_FILENAME): else strcpy(ftin, dectoarch(dim_y)): fprintf(spec_fp, '5440 S-9.2f Ss\n', dim_y, ftin): if (duct_number) strcpy(dim_filename, VERTICAL_DIM1_FILENAME): else strepy(dim_filename, VERTICAL_DIMO_FILENAME): I rotation_angle - 0: fprintf(spec_fp, 'tCLIENT Ss S9.2f S9.2f 1.0 1.0 S3d\n', 131 dim_filename, dim_x, dim_y, rotation_angle): I I if (fclose(spec_fp) -- -1) I printf('\nERROR 110: Unable to close drawing specification file Ss.', filename); display_message('MESAllO', TIL_KBHIT): return (2): I return (0): /* write_drawing_spec_file ‘I APPENDIX G Listing of Management Recommendations Text File S/VR 110 name S1.30s SIVR 111 company S1.30s SIVR 112 address S1.30s SIVR 113 city S1.30s SIVR 114 state S1.15s SIVR 115 zip_code Sl.15s SIVR 116 phone S1.1Ss SIVR 150 post_spacing S2d SIVR 155 post_size S7.7s SIVR 171 storage_width S4.1f SIVR 172 storage_length S4.1f SIVR 175 bushel_capacity S7.0f S/VR 176 peak_height S3.1f SIVR 177 width_of_peak_height S3.1f SIVR 180 higher_sidewall_height S3.1f SIVR 181 lower_sidewall_height S3.1f S/VR 182 higher_endwall_height S3.1f SIVR 183 lower_endwall_height S3.1f SIVR 190 maximum_piling_height S3.1f SIVR 205 desired_number_of_ducts S2d SIVR 207 number_of_ducts S2d S/VR 208 lower_side_air_path_ratio S3.2f SIVR 209 higher_side_air_path_ratio S3.2f SIVR 250 cfm_per_bushel S3.2f SIID DATlO SIDS Client name and address S/AT 06 Watson S/DT 04-07-87 SITK This aeration system has been designed for: S/VR110 S/VRlll S/VR112 S/VRll3, S/VR114 SIVRllS S/VR116 The following listing summarizes information about the aeration system: SIEX SIID DATZOa SIDS Interview data -- grain SIAT DG Watson S/DT 04-07-87 SITK Grain -- shelled corn SIEK SIID DAT20b SITK Grain -- soybeans SIEK SIID DAT20c SITK Grain -- wheat 132 S/EX SIID SITK S/EX SIID SIDS S/AT SIDT S/TX SIBX SIID S/TX SIEX SIID SIDS SIAT SIDT SITK Post SIEK SIID SITK SIEK SIID S/DS SIAT S/DT SITK S/EX SIID S/TX SIEK SIID SIDS S/AT S/DT SITK DATZOd Grain -- DAT25a 133 grain sorghum Interview data -- structure DG Watson 04-07-87 Building -- DATZSb Building -- DAT30a Interview data -- frame DG Watson 04-12-87 Construction -- spacing -- DAT30b Construction -- DAT35a Interview data -- liner DG Watson 04-07-87 existing DOV construction post frame SIVRlSO' non-post frame Grain liner information -- not requested DAT35b Grain liner information -- requested DAT4O Interview data -- storage dimensions DG Watson 04—07-87 Storage size -- Sidewall depths: higher side wall -- lower side wall -- higher end wall -- lower end wall -- Maximum piling height -- Bushel capacity -- Actual peak height -- Width of peak -- S/EX SIID SIDS SIAT S/DT SITX SIEK SIID SITX S/EX SIID SIDS SIAT S/DT S/TX S/EX SIID DAT45a Interview data -- number 06 Watson 04-07-87 Ducts -- DAT45b Ducts -- DATSOa t/va171' by SIVR172' S/VR180' S/VR181' S/VR182' S/VR183' S/VR190' S/VR175 S/VR176' S/VR177' of ducts computer selected SIVR207 user requested SIVRZOS computer used SIVR207 Calculated air path ratios DG Watson 04-12-87 Air path ratios: from lower side wall -- from higher side wall -- DATSOb S/VR208 S/VR209 134 SITK Air path ratios: from lower end wall -- SIVR208 from higher end wall -- S/VR209 SIEK SIID DATSSa SIDS Interview data -- fan arrangement SIAT DG Watson SIDT 04-07-87 SITK Fan arrangement -- end or middle placement SIEK SIID DATSSb SITK Fan arrangement -- and placement only SIEK SIID DATSSc SITK Fan arrangement -- middle placement preferred SIEK SIID DAT60a SIDS Interview data -- fan type SIAT DG Watson SIDT 04-07-87 SITK Fan type -- axial SIEK SIID DAT60b SITK Fan type -- centrifugal SIEK SIID DAT65a SIDS Interview data -- duct direction SIAT DG Watson SIDT 04-07-87 SITK Duct direction -- lengthwise SIEK SIID DAT65b SIDS Interview data -- duct direction SIAT 06 Watson SIDT 04-07-87 SITK Duct direction -- widthwise SIEK SIID DAT70a SIDS Interview data -- duct type SIAT DG Watson SIDT 04-07-87 SITX Duct type -- plastic SIEK SIID DAT70b SITK Duct type -- spiral-10k metal SIEK SIID DAT70c SITK Duct type -- round metal SIEK SIID DAT70d SITK Duct type -- half-round metal SIEK SIID DAT75 SIDS Interview data -- airflow rate SIAT DG Watson SIDT 04-07-87 SITK Airflow rate -- SIVRZSO cfm/bu SIEK SIID GENl SIDS Definition: SIAT RC Brook SIDT lODec86 SITK GENERAL COMMENTS ON FLAT STORAGES: Flat grain storages are buildings in which neither the length nor 135 width is less than two times the height of the grain on the sidewall. Otherwise, the grain tends to bridge, as does ground feed, thus increasing the sidewall pressure. SIEK SIID GEN2 SIDS Limitation - without aeration: SIAT RC Brook SIDT lODec86 SITK The use of buildings for grain storage is not recommended for more than 1 to 2 months storage if not equipped with an adequate aeration storage. SIEK SIID GEN3 SIDS Limitation - with aeration: SIAT RC Brook SIDT lODec86 SITK The use of buildings for grain storage when adequate aeration is installed is not recommended for storage of grain past late spring. SIEK SIID FLR1 SIDS Floors in existing buildings: SIAT RC Brook SIDT lODec86 SITK SPECIFIC COMMENTS ON THIS AERATION PLAN: Open areas in existing buildings frequently have irregular and cracked concrete floors or earth floors. Such floors normally have no vapor barrier. A vapor barrier of 4-6 mil plastic sheet should be placed on the floor before the aeration ducting and grain. Care should be exercised when filling the storage so that the vapor barrier is not broken or torn. SIEK SIID FLR2 SIDS Floors in new buildings: SIAT RC Brook SIDT lODec86 SIKW SITK SPECIFIC COMMENTS ON THIS AERATION PLAN: Before pouring the concrete floor in a new building designated for grain storage, place a vapor barrier of 4-6 mil plastic sheet on the ground. When pouring the concrete, care should be exercised that the vapor barrier is not broken or torn. SIEK SIID SWSI SIDS Sidewall Strength - acceptable SIAT RC Brook SIDT lODec86 SIKW SITK The grain will be piled, at most, S/VR180 feet on the sidewall of your building. With the posts spaced SIVRlSO feet on center, a post size of at least SIVRlSS is required. The smaller post dimension must face the grain. Higher grain depths or smaller posts will likely to cause structural damage to the building. SIEK SIID SW52 SIDS Sidewall Strength - unacceptable SIAT RC Brook SIDT lODec86 S/KW 136 SITK WARNING: The grain will be piled, at most, S/VR180 feet on the sidewall of your building. With a posts spacing of SIVRlSO feet on center, you are likely to cause structural damage to your building. Either add posts to the building or use a grain retaining wall. SIEK SIID SWSJ SIDS Sidewall Covering SIAT DG Watson SIDT 5-5-87 SIKW SITK Grain liners can be constructed by adding a stud wall between posts or by building portable restraining walls. Request a copy of a grain liner plan for adding a stud wall or the Midwest Plan Service plan for portable grain bulkheads. SIEK SIID SW54 SIDS Non post frame construction SIAT DG WATSON SIDT 28Apr87 SIKW SITK WARNING: Contact the manufacturer or builder of your building to determine if the walls of the building will support the grain depth of SIVR18O feet. If the manufacturer or builder cannot answer this question, contact an agricultural engineering consultant. DO NOT pile grain on the walls until you have verified the ability of the walls to support the grain. SIEK SIID RFCl SIDS Roofing Considerations -- exist building SIAT RC Brook SIDT lODec86 SIKW SITK Consider carefully the roof of an existing building. Corrugated metal roofing nailed directly to a wood rafter or truss invariably leaks water somewhere. A sealant should be used around nail heads to minimize leakage. SIEK SIID RFC2 SIDS Roofing Considerations -- new building SIAT RC Brook SIDT lODec86 S/KW SITK Consider carefully the type of roofing used. Corrugated metal roofing nailed directly to a wood rafter or truss invariably leaks water somewhere. A shingled roof is preferable to help eliminate water leakage and the potential grain spoilage problems. SIEK SIID DCTP10 SIDS Duct Placement -- not recommended SIAT 06 Watson SIDT June 6, 1987 SIKW SITK WARNING: This design is based on a 'user selected' number of ducts. This arrangement is not recommended. The air path ratios as listed above are too high to insure adequate aeration of the 137 grain. If this design is used the risk of grain spoilage is greatly increased. SIEK SIID MANl SIDS Caution on airflow delivery SIAT RC Brook SIDT lODec86 SIKW SITK GRAIN MANAGEMENT COMMENTS: The design airflow may be greater than the effective delivered airflow. Grain with excess amounts of fines or foreign material will increase the static pressure caused by the grain. The change in static pressure will lower the delivered airflow for that general area of the grain storage. The grain directly between the ducts will also receive a lower airflow than the grain directly over the ducts. Careful observation of the grain surface during cooling is important to help insure adequate cooling of all the grain in storage. SIEK SIID MAN2 SIDS Temperature Cables if Volume > 30,000 bushels SIAT RC Brook SIDT lODec86 SIKW SITK A temperature monitoring system should be installed in the grain storage. A monitoring system consists of temperature sensing cables and a conveniently located monitor for temperature display. SIEK SIID MAN3 SIDS Airflow direction SIAT RC Brook SIDT lODec86 SIKW SITK The fans should be operated for upward airflow in order to help ensure as uniform an airflow as possible along the length of the duct(s). The upward airflow also helps the management of the cooling phase by allowing observation of the air exiting the surface of the grain mass which will help show the progress of cooling in different areas of the storage. SIEK SIID MAN4 SIDS Fan type SIAT RC Brook DG Watson SIDT lODec86 June 6, 1987 SIKW SITK Generally, axial flow fans are used for grain storage aeration because they are less expensive for the low static pressures involved than centrifugal fans. Ducts are always sized for a specific fan output. Do not use a fan size different from the one specified with having the duct size recalculated. SIEK SIID MANS SIDS Gain Management Practices SIAT RC Brook SIDT lODec86 SIKW SITK Proper management practices are essential to successful storage of grain. Grain should be clean, dry and cool to insure the maintenance of quality during storage. A regular inspection of the grain during the storage period will help to avoid storage 138 problems. For more details, see Michigan State University Cooperative Extension Service bulletin E-1431. SIEK APPENDIX H 'C' Source Code of Rules for Printing Management Recommendations int man_rec_selection_rules() I /' man_rec_selection_rules “I float higher_wall, design_apr: int man_rec_counter - 0: select_man_rec('DATlO', Sman_rec_counter): switch (design_data.grain_type) I case 0: select_man_rec('DAT20a', Gman_rec_counter): break: case 1: select_man_rec('DAT20b', £man_rec_counter): break: case 2: select_man_rec('DAT20c', 5man_rec_counter): break: case 3: select_man_rec('DAT20d', sman_rec_counter): break: I if (design_data.new_building) select_man_rec('DAT25b', £man_rec_counter): else select_man_rec('DAT25a', £man_rec_counter): if (design_data.construction_type) select_man_rec('DAT30b', £man_rec_counter): else select_man_rec('DAT30a', Gman_rec_counter): if (design_data.liner_info) select_man_rec('DAT35b', iman_rec_counter): else select_man_rec('DAT35a', £man_rec_counter): select_man_rec('DAT40', 8man_rec_counter); if (design_data.desired_number_of_ducts) select_man_rec('DAT4Sb', £man_rec_counter): else select_man_rec('DAT4Sa', £man_rec_counter): if (design_data.duct_direction) select_man_rec('DAT50b', iman_rec_counter): else select_man_rec('DAT50a', iman_rec_counter): switch (design_data.desired_fan_arrangement) I case 0: select_man_rec('DAT55a', £man_rec_counter): break: case 1: select_man_rec('DAT55b', iman_rec_counter): break: case 2: select_man_rec('DAT55c', Gman_rec_counter): 139 140 break: I if (design_data.fan_type) select_man_rec('DAT60b', £man_rec_counter): else select_man_rec('DAT60a', Eman_rec_counter): if (design_data.duct_direction) select_man_rec('DAT65b', Eman_rec_counter): else select_man_rec('DAT65a', iman_rec_counter): switch (design_data.duct_type) 1 case 0: select_man_rec('DAT70a', 8man_rec_counter): break: case 1: select_man_rec('DAT70b', £man_rec_counter): break: case 2: select_man_rec('DAT70c', £man_rec_counter): break: case 3: select_man_rec('DAT70d', aman_rec_counter): break: I select_man_rec('DAT75', Sman_rec_counter): select_man_rec('GEN1', eman_rec_counter): select_man_rec('GEN2', sman_rec_counter): select_man_rec('GEN3', Sman_rec_counter): if (design_data.new_building) I select_man_rec('FLR2', £man_rec_counter): select_man_rec('RFC2', Gman_rec_counter): I else I select_man_rec('FLR1', £man_rec_counter): select_men_rec('RFCl', iman_rec_counter): I if (design_data.construction_type) select_man_rec('5W54', 6man_rec_counter): else if (design_data.post_spacing !- 0) I if (design_data.post_size[0] -- '\0') select_man_rec('SW52', £man_rec_counter): else select_man_rec('SW51', Eman-rec_counter): I if (design_data.liner_info) select_man_rec('SWS3', £man_rec_counter): if (design_data.duct_direction -- LENGTHWISE) higher_wall - design_data.higher_sidewall_height: else higher_wall - design_data.higher_endwall‘height: if (higher_wall >- factor.depth_deep) design_apr - factor.ratio_deep: else design_apr - factor.ratio_shallow; if (larger(design_data.lower_side_air_path_ratio, design_data.higher_side_air_path_ratio) > design_apr) select_man_rec('DCTP10', Sman_rec_counter): select_man_rec('MAN1', 5man_rec_counter): if (design_data.bushel_capacity > 30000) select_man_rec('MAN2', £man_rec_counter); select_man_rec('MAN3', iman_rec_counter): select_man_rec('MAN4', £man_rec_counter): select_man_rec('MAN5', Gman-rec_counter): return (man_rec_counter): /* man_rec_selection_rules '/ APPENDIX I information Sheets and Evaluation Instruments Sent to Reviewers Before On-Site Visit Information sheets and evaluation instruments sent to the reviewers before the on-site visit consisted of the following: case study overview and instructions information sheet case study 1 description case study 1 cross-sectional view of grain storage case study 1 floor plan for sketching and dimensioning component placement case study 1 table of component specifications case study 1 recommendations list case study 2 description case study 2 cross-sectional view of grain storage case study 2 floor plan for sketching and dimensioning component placement case study 2 table of component specifications case study 2 recommendations list questionnaire for aeration system design guidelines 141 142 AERATION SYSTEM DESIGN FOR FLAT GRAiN STORAGES Case Studies Overview of «dualism plan MawaumsymemdesignwogmnhubeendewbpedwhichgenwemscuMaemflonsysem design Wmmadesimflominiommflonabommeg'ainsbmgedssaibedbyme proqam userand the design guidelines built intothe pregam. As anexpert in aeration system design. youhawbeenukedbwahabflncontpumrprogmnfuedmcdcunemwdusabiflty. This muonldededmotwophasesandmeacfivllesforeadfphaeeueasbliows: Phaei-beioreouron-sitsvisit: ' desigringmaerationsymem(byyomumldym8mds)brourtwocasestudes ' sumrlzhgaerationsystemdesignguideiines ’ selectmgoiomornyocasesmdesiromywrfiissiortmemringihehands-onevaiuation Phaez—mlrmgouron-sltsvisit: ' hands-mhtroductlontotheconputerprogmn soivingceseshdeswlththeoonputerprogrem comparing computer solutions to your solutions Mdliierenoesindssimmethodoiogy summarizing resutsof technical command usability evaluation Instructions for case studies Twocessstudissareatfached. Yoursoknionoithesscasestudleswiilasmstusinevaiuatingthedesigw widelinasuasdhmeconputerprogsm. ForyoucomenienceJiveworksheetsareprovidsdioresch cessmdy. flucomemwuseofmeworieheemisasioliowa: Worksheet Cornet-mucus m ammmmwmwmmmmm a2 aossWdMngoic-esUdywimgridbrclarlflceuonoigrainpmfle #8 lioorplan (withgrid)oicesestudystorege for sketching component piacernent u tsbieoicomponentspsclficsioreiorilstingdeeimremflts 05 Whaflstiorilshgmydesiminpiemeflaflonandmnsmmem recommmrthscasestudy Pleasesoivemecssesmdesandimemeworksheemtodescribeyourdesign. Wehuemsdamsbryoummehwmldngyoudaimwmwmdxu. “mmwmunmuawummmmm Astheiinalstepinpreparhgioroucnmtevidtmhssesehctomortwocasestudssirunymuflies. Youcssesmdeswilbetmeddurhgmehands-onevekmfionofuncombrprog'm During the on site visit. we will pick up your completed case studies and questionaire. 143 AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAGES Case Study 1 A grain producer needs an aeration system for an existing pole barn in which shelled corn will be stored from November to August. Grain will be dry, clean and cool. Storage specifications are as follows: width 60.0 it length 120.0 it grain depths: side walls 6.0 it end walls 0.0 it maximum peak 12.0 it The piling height is limited to 12 ft by the trusses, but equipment is available to level the pile in the center to maximize storage capacity (refer to cross sectional view of case study 1). Bushel capacity of this storage is 49.800 bushels. Assume that the structure can support the grain depths listed above. The grain producer's preferences regarding equipment and placement are: duct type : plastic aeration tubing duct direction : lengthwise in storage fen type : axial fan placement : either ends or middle of ducts m’r flow rate : 1/10 cfmlbu The grain producer requests your assistance in determining the number and placement of ducts and sizing of ducts. fans and ian-to-duct connectors. The above preferences may be changed if you feel it is important to achieve a good design. The attached cross sectional view of case study 1 is provided for your convenience. Please complete the table of component specifications to summarize the results of your design and sketch the placement of components on the floor plan provided. On the recommendation sheet. list any design implementation or management recommendations which you would make to the grain producer in addition to the component list and floor plan. If you need additional information contact Dennis Watson or Roger Brook at (517) 353- 7888 or 353-4458. Case Study 1 - Worksheet #1 144 AERA'ITON svsrsm DESIGN FOR FLAT GRAIN STORAGES Case Study 1 CrosaPSectionai View of Grain Storage Ll *lil“ .1: 60’ 4-l' Vertical grid lines in grain area are 2' on center. Case Study1 -- Worksheet #2 145 a. .8653 .. .Sam 88 cacao so .« 2e e2... 25 32:2. 23 .8533: .03 1. .ceEeeeE Eocene—co mes—3.32:5 o:- 23:28.» ac. ca... Loo.“— . >36 38 mmosaohm 22:0 5.... so“. 2033 55>» zo=<¢m< 146 AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAGES Case Study 1 Table of Component Specifications When completing the following table of component sizes, place the floor plan drawing with the printed text in the normal reading position. Reference the ducts by number with duct # 1 being closest to the lower left corner of the drawing. Component Size Duct Number I I I 2 I 3 I 4 I 5 I 5 I 7 I I I I I I I I I diameter. in | l I l I | I I I I I I I I I I length. It I | I | I I I I I I I | I I I I number of fans | I I l I l I | Ian diameter, in | I I I I | I I fan horsepower. hp l I l l l l l I fan cfm output. cfm l I I I l l I l I static pressure. in H20 | | I I I I | l fan connector diameter. in | | l | I I | l Case Study 1 -- Worksheet #4 147 AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAGES Case Study 1 Recommendations List When an expert works with a client on a design problem, he often provides additional recommendations to the client for implementation and management of the design. For the case study, list the design implementation and management recommendations and any supplemental information you would provide to the client. List of Recommendations Case Study 1 -- Worksheet #5 148 AERA'I10N SYSTEM DESIGN FOR FLAT GRAIN STORAGES Case Study 2 A grain producer needs an aeration system for an existing pole barn in which shelled corn will be stored from November to June. Grain will be dry and cool. but the producer does not use a grain cleaner. Storage specifications are as follows: width 50.0 it length 60.0 ft grain depths: side walls 6.0 it end walls 6.0 it maximum peak 12.0 it The piling height is limited to 12 it by the trusses, but equipment is available to level the pile in the center to maximize storage capacity (refer to cross sectional view of case study 2). Bushel capacity of this storage is 23.200 bushels. Assume that the structure can support the grain depths listed above. The grain producer's preferences regarding equipment and placement are: duct type : round metal aeration tubing duct direction : widthwise in the storage fan type : axial fen placement : ends of duct only air flow rate : 1/5 cfm/bu The grain producer requests your assistance in determining the number and placement of ducts and sizing of ducts. fans and fan-to-duct connectors. The above preferences may be changed if you feel it is important to achieve a good design. The attached cross sectional view of case study 2 is provided for your convenience. Please complete the table of component specifications to summarize the results of your design and sketch the placement of components on the floor plan provided. On the recommendation sheet. list any design implementation or management recommendations which you would make to the grain producer in addition to the component list and floor plan. if you need additional information contact Dennis Watson or Roger Brook at (517) 353- 7888 or 353-4456. Case Study 2 - Worksheet #1 149 AERATION SYSTEM DESIGN FOR FLAT GRAIN STORAGES Case Study 2 Cross-Sectional View of Grain Storage LI ‘I‘IIT at: s 50' 4» Vertical grid lines in grain area are 2' on center. Case Study 2 -- Worksheet #2 150 S .8553 -- m 5.5 88 .LScee co .« 2e sec: 2.6 32:2. use .3553: JI .n be .ceEeoe... Essex—Eco 9.303.565 o:- 2.288% 3. 55 Loo.“— « scan 38 303.9% 22:6 .53“. mo“. 2033 Sage ZOF