rassés This is to certify that the thesis entitled CONSERVATION OF ENERGY IN THE RESIDENTIAL BUILDING COMMUNITY VIA COMPUTER APPLICATIONS presented by Richard Joseph Patterson has been accepted towards fulfillment of the requirements for Ph.D. degreeinfigflflmnal Engineering Technology .) , / 7’ a 9' c V/é ’l 4 _ x6? (L/éff/Ceé/ Major professor 0 Date “’évéfii/Z/ZI/ / / / 0.7639 MSU LIBRARIES m \' RETURNING MATERIALS: Place in book drop to remove this checkout from your record. FINES will be charged if book is returned after the date stamped below. CONSERVATION OF ENERGY IN THE RESIDENTIAL BUILDING COMMUNITY VIA COMPUTER APPLICATIONS By Richard Joseph Patterson A DISSERTATION Submitted to Michigan State University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Agricultural Engineering Department 1981 7// "/ '. ‘4 (' ABSTRACT CONSERVATION OF ENERGY IN THE RESIDENTIAL BUILDING COMMUNITY VIA COMPUTER APPLICATIONS By Richard Joseph Patterson Surveys agree that between 20 to 30 percent of the total United States energy consumption is expended to satisfy the energy needs of human dwellings. Approximately 70 percent of the energy expended in the home is for the purposes of space heating and cooling. This magnitude of consumption, combined with the scarcity in supply of the energy forms used in the home and the increasing costs of available energy supplies, attest to the need for upgrading the energy performance of the residence. This thesis proposes the energy performance of the residence be improved through: (1) application of computer programs which evaluate the energy performance of residences and (2) establishment of an energy/ housing computer capability network which will allow programs addressing building energy performance to be accessed by.users in the residential building community. Three computer programs, IBUC, TRNSYS, and NBSLD, were selected as being representative of existing enerQY/housing programs which address building energy performance. Each program is applied to a typical residence. Using the application as a common basis, each program is discussed with respect to achieving input and output, heat transfer methodology, aspect of building energy performance addressed, and energy Richard Joseph Patterson performance information produced. The three programs range from those utilizing simple simulation techniques employing algebraic equations to those employing sophisticated mathematical models using differential equations. The central processor times and the central memory require- ments vary accordingly. A plan for expanding energy/housing computer capability in the residential building community is proposed. The plan for expanding computer capability involves two key developments. One is the selec- tion of the local governmental unit as the site in the residential building community to serve as an energy/housing computer capability resource center. The local computer capability resource center will provide computer access facilities and user assistance so that a library of energy/housing programs may be accessed and utilized. The second development is the formation of a group of cooperating agencies. This group is composed of representatives from agencies in the residential building community with energy/housing expertise and this group has the responsibility for the development, implementation, and continued operation of the energy/housing computer capability network. ACKNOWLEDGMENTS Many people have contributed, in many ways, to the completion of this work. A thank you is extended to each and every one. Appreciation is expressed to those serving on the Guidance Com- mittee: Professors Bakker-Arkema, Bickert, Mackson, and Lloyd. Also to Dr. Brook and Mr. Cron.for their participation in the oral exam- ination. There are several individuals to whom special appreciation must be expressed, because their contributions were of a very special nature. A special thank you to friend and major advisor, F. w. Bakker- Arkema. Without his special efforts in the way of timely inspiration, guidance, and understanding, this objective would not have been achieved. To Mom and Dad Patterson, thank you for the support that only parents can give. To Florence and Fred Dalzen, thank you for the support of all types that you have given. To "Jut," "Jumpy" ("Loopy"), "Tyke," and ”Teeny," a very special "gracias!" ii TABLE OF CONTENTS LIST OF TABLES .......................... LIST OF FIGURES ......................... I. 2. 3. 4. 3.l Building Energy Performance: A New Priority . . . . 3.2 Energy Consumption and Potential Savings ...... 3.3 Emergence of Building Energy Performance Criteria ...................... 3.4 New Approach to Building Design and Construction .................... 3.4.l Sizing of conditioning equipment ...... 3.4.2 Consideration of factors influencing building energy performance ......... 3.5 Evaluating Building Energy Performance With the Air of a Computer ............... 3.5.l Computer: an appropriate tool ....... 3.5.2 Existing energy computer programs ...... .5.2. energy calculation sequence . code compliance .......... load and energy analysis programs . auditing programs ......... the IBUC program .......... the TRNSYS program ......... the NBSLD program ......... “0000000000“ 566666 566666 6665666 Program sources ............... Computer access networks .......... Proper application of computer capability ................. 000000 010101 01-500 APPROACH TO THIS STUDY ................. vii THE IBUC PROGRAM .................... 25 5.1 The Purpose of IBUC ................ 25 5.2 Input TO IBUC ................... 28 5.3 Output From IBUC ................. 29 5.4 IBUC Methodology ................. 32 5.4.1 The heating multiplier ........... 34 5.4.2 The energy cost value ........... 39 5.4.3 The heating factor ............. 40 5.4.4 The savings factor ............. 40 5.5 Summary Of the IBUC Program ........ ‘. . . . 41 THE TRNSYS PROGRAM ................... 43 6.1 Purpose Of TRNSYS ................. 43 6.2 Individual TRNSYS Modules ............. 45 6.2.1 Module identification ........... 45 6.2.2 Module parameters ............. 49 6.2.3 Individual module inputs .......... 49 6.2.4 Module derivatives ............. 50 6.3 Program Formulation Examples ........... 51 6.3.1 TRNSYS program: module TYPE 12 ...... 52 6.3.2 TRNSYS program: modules TYPE 17, 18, and 19 ................. 58 6.4 TRNSYS Methodology ................ 65 6.4.1 TRNSYS module TYPE 12 ........... 55 6.4.2 TRNSYS modules TYPE 17, 18, and 19 ..... 67 6.4.2.1 TYPE 17 wall ........... 67 6.4.2.2 TYPE 18 room ........... 59 6.4.2.3 TYPE 19 room and basement ..... 70 6.5 Summary of the TRNSYS Program ........... 72 THE NBSLD PROGRAM ................... 74 7.1 Purpose of NBSLD ................. 74 7.2 Input to NBSLD .................. 75 7.3 Output from NBSLD ................. 81 7.4 NBSLD Methodology ................. 88 7.4.1 Factors describing heat loss and heat gain ................. 90 7.4.2 Energy exchange scheme ........... 91 7.4.3 Heat balance equations ........... 92 iv IO. 11. 12. 13. 7.4.4 Conduction transfer functions ......... 95 7.4.5 NBSLD simulation formats ........... 97 7.5 Summary of the NBSLD Program ............. 99 CAPABILITIES AND LIMITATIONS OF IBUC, TRNSYS, AND NBSLD ......................... 101 8.1 IBUC, TRNSYS, and NBSLD vs. Ideal Energy/ Housing Program ................... 101 8.2 Major Deficiencies of IBUC, TRNSYS, and NBSLD . . . . 104 8.2.1 Quality of workmanship ............ 104 8.2.2 Building energy economics ........... 105 EXPANSION OF COMPUTER CAPABILITY IN THE RBC ........ 108 9.1 The Residential Building Community .......... 109 9.1.1 Consumers in the RBC ............. 109 9.1.2 Suppliers in the RBC ............. 110 9.1.3 Regulators in the RBC ............. 111 9.2 Existing Computer Capability in the RBC ....... 111 9.2.1 Computer capability - large organizations ................. 112 9.2.2 Computer capability - small organizations and individuals ......... 113 9.3 Energy/Housing Information Needs of the RBC ..... 115 9.4 Plan for Expanding Computer Capability in the RBC ...................... 118 9.4.1 Expanded public service role of the local governmental unit ............ 118 9.4.2 Group of cooperating agencies ......... 121 9.4.3 Funding the energy/housing computer capability network .............. 123 CONCLUDING DISCUSSION ................... 126 10.1 Energy/Housing Computer Programs .......... 126 10.2 Expansion of Computer Capability .......... 129 CONCLUSIONS ........................ 132 SUGGESTIONS FOR FUTURE NORK ................ 134 REFERENCES ........................ 135 APPENDIX A - EXCERPTS FROM ASHRAE STANDARD 90A-80 AND MICHIGAN ENERGY CODE ......... 141 APPENDIX B - COMPLETED INPUT FORM FOR THE IBUC PROGRAM .................. 154 APPENDIX C - COMPLETED INPUT FORM FOR THE NBSLD PROGRAM .................. 160 vi LIST OF TABLES Table Page 5.1 Input values to the IBUC computer program describing the example residence .............. 27 5.2 Effect Of geographic location on heating multiplier values and the effect of heating multiplier values on estimated yearly savings from the IBUC program ..... 38 8.1 Characteristics of the IBUC, TRNSYS and NBSLD computer programs ..................... 102 8.2 Economic parameters required for a life cycle cost analysis of building energy performance options ...... 106 vii Figure 5.1 Output from the IBUC computer program showing the estimated dollar savings for the example residence . . . . 5.2 IBUC calculation sequence for gas heating ........ 6.1 The type of individual module information required for a TRNSYS program module ................. 6.2 Example input values for a typical TRNSYS program component module ..................... 6.3 An example block diagram of a complete program using the LIST OF FIGURES methodology of the Degree-Hour TRNSYS module ... . . . . . . Actual input information for the example TRNSYS program depicted in Figure 6.3 .................. Output from the example TRNSYS program depicted in Figure 6. 3 ........................ An example block diagram of a complete program using the methodology of the TYPE 17, 18, and 19 TRNSYS modules Input information for the TRNSYS program depicted in Figure 6.6 ........................ Output from the TRNSYS program depicted in Figure 6.6 Input values to the NBSLD program describing the example residence .................... Type of output produced when the NBSLD program is run in the Design Day mode (RUNTYP = 2) ......... Design Day heating load output from the NBSLD program Hourly Design Day heating load output from the NBSLD program . ..................... Type of output produced when the NBSLD program is run in the Simulation mode (RUNTYP = l) ......... viii Page 30 33 46 47 53 55 57 59 62 64 82 83 84 - Figure Page 7.6 Example of hour-by-hour simulation output from the NBSLD program ...................... 89 7.7 Simplified illustration of the energy exchange process simulated by the NBSLD program ........... 93 ix 1. INTRODUCTION Of all the energy expended in the United States approximately 23.5 percent (Johnson, 1976a) is consumed for various purposes in the resi- dence. Approximately 87.5 percent of the residential energy expendi- ture is used for the purposes of comfort space conditioning (73.5%) and domestic water heating (14%) (Johnson, 1977a). These percentages repre- sent consumption conditions of most of the United States' present housing stock which was estimated to be 78 million units in 1975 (Johnson, 1977a). Most existing dwellings were designed and built at a time when energy was readily available and was comparatively low in price. Conse- quently, the energy performance of these buildings was not given a high priority. In the present era Of increasing energy costs and uncertain availability, building energy performance has become a high priority. Existing homes or new homes built using past design and construction practices are cOnsidered wasteful'of energy resources and are expensive to maintain at customary comfort levels. New energy performance criteria for dwellings are evolving that reflect the present energy situation. Shaping the new standards are the factors of potential energy savings (patriotic incentive) and/or potential dollar savings (economic incentive). Through legislation (Act No. 230 of Public Acts of 1972) an energy performance standard, ASHRAE Standard 90-75, was adopted in 1977 to become the initial mandatory energy code for new buildings in the State of Michigan. Discussion of both the Mich- igan Energy Code, ASHRAE Standard 90-75, and ASHRAE 90A-80 is included in sections 3.3 and 8.3 and Appendix A of this thesis. For dwellings to meet newly developing energy performance criteria and/or comply with energy codes, a re-evaluation of the methods, materials, and systems of construction used in the design and building of new homes and in the retrofitting of existing homes is in order. The re-evaluation referred to above comprises numerous options for improving the energy performance of both new and existing dwellings. Each option requires the simultanebus consideration of many interrelated factors in order to determine its relative economic and/or thermal merits. A thorough energy performance analysis, involving more than a few energy saving options, quickly becomes too complex for the individual. With the aid of a computer and an appropriate energy/housing computer program the analysis can be performed rapidly and accurately, providing an evaluation of each option considered. Having the information provided by the com- puter analysis, the individual can proceed to make well informed decisions regarding the improvement of building energy performance. Petersen (1974) comments on the significant need for making infor- mation concerning the various options for improving the energy perfor- mance of dwellings available to those who can benefit most by it. One way of accomplishing this is to extend computer capability (computing facilities and library of energy/housing programs) into the residential building community (RBC), making it available to individuals concerned with improving the energy performance Of buildings. For an extension effort of this kind to be realized a viable plan is required which addresses and resolves the problems of energy/housing program avail- ability and computing facilities accessibility. There are many computer programs in existence which address an array of energy/housing problem areas. Many of these programs are written by and for persons with heat transfer and computer backgrounds. With the exception of some energy code officials and home builders who have had exposure to the Michigan Energy Code, most potential program users in the RBC do not have computer or heat transfer knowledge.. New energy/housing computer programs need to be developed and/or existing programs modified such that their usage is within the capabilities of potential users in the RBC. . Existing computer programs vary in size as well as in the particular aspect of building energy performance addressed. Large programs require computers having large central memory (>'l70 k) and central processor capabilities. Computing facilities of this Size are normally associated with academic institutions, corporations, or privately owned companies in the business of providing computing services. Some Of the smaller energy/housing programs may Operate on microcomputers (< 20 k RAM). Computing facilities of this size are increasing in popularity and decreasing in cost. Energy/housing computer programs must be accessible to potential users if they are to provide the information needed to aid in making decisions on energy/housing matters. Telecommunication systems have developed to the point that access to powerful computer facilities is possible wherever an ordinary telephone is located. However, providing computer access is complicated by the diverse composition of the RBC. In addition most potential users presently cannot justify acquiring their own access facilities. There is presently some computer capability available in the RBC. That Computer capability which is presently available does not reach enough of the potential users in the RBC nor does it provide the variety of energy/housing computer programs needed. A network of access sites is required to expand computer capability to those in the diverse RBC who do not now have this service. To establish an energy/housing network a coordinated, cooperative effort is required. This can only be accom- plished by an organization having the enerQY/housing expertise and the willingness to accept the challenge and the responsibility. 2. OBJECTIVES The primary Objective of this study is to propose a plan for improving the energy performance of residences by extending computer capability (a library of energy/housing computer programs and facilities to access these programs) to the residential building community. The primary objective incorporates the following secondary objectives: a. Assess existing computer programs addressing energy/housing. subjects by selecting programs of three different levels of ability to predict the energy performance of residences and comparing their characteristics, capabilities, and limitations. b. Develop a specific action plan for the residential building community which will facilitate the selection and utilization of computer programs generating information needed to make better informed energy/housing decisions. 3. REVIEW OF LITERATURE 3.1 Building Energy Performance: A New Priority Energy performance has become a high priority among the character- istics by which buildings are judged. The priority level that a build- ing characteristic attains at any given time is influenced by many factors (costs, availability, style, technology, etc.) associated with the particular characteristic. When something happens that causes the influencing factors of one building characteristic to change, all of the characteristics undergo a reranking of priority. The shuffling of building characteristic priorities is a normal process that is continuous and gradual. The sudden change in energy costs and availability Of some energy sources directly affected building energy performance and caused a sudden reranking of building character- istics with energy performance gaining a much higher priority. When energy was readily available and relatively inexpensive, there was little incentive for energy conservation in buildings. This was indicated by the fact that many homes built prior to 1960 have less than three inches of ceiling insulation and none in the walls, under floors or over unheated areas. They were also lacking in both heat gain and loss protection for windows. These constrUction practices were not irrational with respect to energy conservation (Petersen, 1974), since they reflected the level of priority that energy performance held under the circumstances at the time the homes were built. 3.2 Energy Consumption and Potential Savings Estimates vary as to the amount of energy expended, as well as the potential for reducing this amount, in providing comfort conditioning, lighting, and operating appliances in buildings. Sparks (1977) stated that close to one-third of the nation's energy is used for these pur- poses. ERDA experts (from Sparks, 1977) indicated that comfort con- ditioning, lighting, and operation of appliances could be achieved.with half as much as is now consumed for these purposes. Roberts in Berry (1975) agreed with the one-third usage figure and estimated that 80 per- cent of this amount is used for comfort conditioning and water heating. They further indicated that approximately 40 percent Of the energy used for comfort conditioning is wasted due to building design, construction practices, and occupant practices. Johnson (1977a) estimated the amount of energy used by each dwelling to be about 200 million btu of primary energy per year. He also indicated that the on-site distribution of energy usage in a single family detached home includes 73.5 percent for comfort conditioning and 14 percent for water heating. The energy performance Of the estimated 78 million residences (Johnson, 1977a) can be improved. Ambrose (1975) referred to the need for developing practical methods for reducing energy consumption in existing dwellings and Landergan (from Berry, 1975) suggested that empha- sis on conservation be directed toward existing structures. Energy con- servation at the single family residence level was advocated by Swenson (1977) as being just as important and beneficial as is conservation in large buildings with comparatively larger energy budgets. Petersen (1974) evaluated various combinations of energy conserving techniques to determine if they would be economically optimal for existing resi- dences. 3.3 Emergence of Building Energy Performance Criteria Individuals seeking relief from increasing utility bills began looking for ways of improving the energy performance of their buildings. This was the beginning of the development of new energy performance criteria to serve as a guide to improve the energy performance of existing homes and in the construction of new buildings. Many publica- tions became available concerning various energy conserving actions applicable to existing buildings (Oviatt, 1975; Petersen, 1974; Federal Energy Administration, 1977). Formal energy performance standards have been developed pertaining to new building construction. ASHRAE Standard 90-75 (ASHRAE, 1975) began development in 1973 with a joint emergency workshop on energy con- servation in buildings (Berry, 1975) and gained final approval in 1975. In 1977, ASHRAE Standard 90-75 was adopted by reference along with several rules to become the Michigan Energy Code (1976). ASHRAE Stand- ard 90-75 has also been used as the technical base for the develOpment of a model energy code (U.S. Dept. Energy, 1977). New building energy performance criteria continue to be developed and existing ones revised. ASHRAE Standard 90-75 has been revised (ASHRAE/IE5, 1980) and a program to develop Building Energy Performance Standards (BEPS) (U.S. Dept. Energy, 1979) is currently underway. In general, these are more complex energy performance criteria than the original ASHRAE 90-75. One reason for this is the consideration being given to the effect, on energy resources, of the form of energy used at the building site (RIF, resource impact factor) and the energy resources consumed in providing that fuel or energy (RUF, resource utilization factor) (ASHRAE/IE5, 1980). To illustrate the intent and approach of ASHRAE Standard 9OA-80 several sections are included in Appendix A. ‘ The energy resources issue is underscored by comments such as those by Smith and Pease (1973). They compare various building materials in terms of the energy used to produce them and in terms of the costs Of their effect on the environment as a result of manufacturing them. Also, Demkin in Berry (1975) discussed a proposed study by Stein to measure the total energy impact of construction materials on the environment. In the case of the ASHRAE Standard (section 12) it was felt that if energy resources were not given consideration the standard would not be addressing the fundamental issue of energy conservation (Coad, 1977). 3.4 New Approach to Building Design and Construction 3.4.1 Sizing of conditioning equipment A re-evaluation of the approach to the design and construction of buildings and their space conditioning means is needed in view of emerging building energy performance criteria. One of the practices in need of examination is that of selecting space conditioning equipment to satisfy the thermal requirements of buildings. Ideally, the equipment selected will have just enough capacity to maintain the desired comfort conditions during times of the most severe weather conditions (ASHRAE, 10 1977 and Sherwood & Hans, 1979). If the equipment does not have the capacity to provide the desired conditions it is undersized. The oppo- site, the selection of equipment that has more capacity to heat or cool than is required by a particular structure, is oversizing. A The practice of oversizing conditioning equipment is more common place than is undersizing. There appear to be three reasons for over- sizing. Black (1977) referred to the conservative or "be sure" design philosophy developed over the years with respect to sizing of heating equipment. Since the penality for oversizing has been less severe than the penality for undersizing, oversized equipment was usually selected. Sherwood and Hans (1979) cited the need for oversized equipment in dwellings to compensate, by brute force, for building design deficiencies. Buffington (1975) indicated that oversizing of equipment is due to the .use of the traditional steady-state calculation methods in determining the heating and cooling load of the building. For whatever reason the selection of oversized equipment occurs, the result is a waste of resources and a sacrifice in the comfort conditions attainable. Over- sized equipment generally operates at reduced efficiency and requires. more energy and materials to manufacture than equipment appropriately sized (Kusuda, 1976). 3.4.2 Consideration of factors influencing buildingAenergy performance Proper sizing of conditioning equipment is only one aspect of the overall strategy for the design and construction of buildings with improved energy performance. A much broadened and refined approach to 11 building design and construction is needed if buildings are to reflect the new, developing energy performance criteria. A new strategy must account for as many of the building energy performance factors as pos- sible. Sherwood and Hans (1979) indicate that the building mass, the relationship of the building to its surroundings (including local cli- mate), and human comfort requirements are factors which influence build- ing design and should be considered. According to Coad (1976) the building industry should abandon singular concepts for a universal market and instead return to the practice of designing buildings for a particular region giving consideration to the local climate and to the materials and methods of construction best suited to that region. The need for a new approach was summarized by Sherwood and Hans (1979) as they pointed out that "the solution to the challenge of more energy-efficient house design obviously lies in more imaginative approaches to this complex problem than in the past. More efficient design will also require more careful engineering, rather than just selection and specification of materials on the basis of outdated rule- of-thumb methods." A similar opinion was expressed by AIA Research Corp., (1976): Buildings are constructed to moderate the extremes of external climate to maintain the building interior within the narrow ranges of temperature and humidity that support occupant com- fort. Building design can begin to accomplish this role by working with instead of against climatic impacts. 12 3.5 Evaluating Building Energy Performance With the Aid of a Computer 3.5.1_ Computer: an appropriate tool For reasons of speed, accuracy and convenience the computer is an appropriate tool to use in evaluating various aspects of building energy performance. In instances where the procedure is rigorOus, taking into account many factors and using SOphisticated techniques, the computer is a necessity. If the program employed is comprehensive and indicates the proper response to the change of the many influencing parameters, the computer can be used to evaluate the sensitivity of various design alternatives (Kusuda, 1976). Burch §t_al, (1975) indicate that the large memory banks Of computers have made it possible to determine the hourly heating and cooling load of buildings as they fluctuate due to varying climatic and building factors. Colliver et_gl, (1976) stated that a dynamic model enables home owners to evaluate the numerous and complex interactions among occupant living habits, structural character- istics, and weather conditions which are unique from one home owner to another. Chen (1976) pointed out that the engineer, architect, and building owner all have an interest in the energy performance of a build- ing and that the computer can be of assistance in providing relevant information to each of them. The simulation capability of a computer is a necessity, according to Tamblyn (1977) and Chen (1976), when dealing with heating and cooling systems with limited heat sources, such as solar energy, in which thermal storage plays a major role. 13 3.5.2 Existing energy computer programs 3.5.2.1 energy calculation sequence Many computer programs are in existence addressing a variety of subjects related to building energy performance. The purposes of such programs include energy auditing, space load calculations, energy con- sumptiOn, energy code compliance, energy costs analysis, and individual system component simulation. These programs fall within an energy cal- culation sequence framework with three basic parts: (1) rate Of heat loss or gain to the conditioned space (building energy load), (2) energy consumption over a given time period (building energy consumption), and (3) building owning and operating costs. The relationship between each of the sequence parts was described by Stoecker (1976) and discussed in part by Black (1977), Crall (1975), and Black and Coad (1976). Building energy load is needed as input information for the building energy con- sumption component. Information concerning energy consumption is required input for the economic analysis part of the energy calculation sequence. Carrying out an energy calculation sequence, or any part of it, can be a very complex or relatively simple task depending on the number of influencing factors accounted for and the methods used to account for them. As stated by Buffington (1975) and Kusuda (1976), determination of the building energy load and building energy requirements may be carried out in a simple manner giving approximate results or they may be carried 14 out in increasing degrees of complexity accounting for more and more Of 'the influencing factors and giving more and more accurate results. 3.5.2.2 code compliance Computer programs are available to determine the compliance of buildings with energy codes and will be utilized more extensively as codes become more comprehensive. Compliance with section four (exterior envelope) of ASHRAE Standard 90-75 is offered through APEC (undated) services using a program, ST090, containing some optimization (with respect to meeting code requirements) capability. ENERCODE is a computer program addressing the subject of compliance of the exterior envelope component of the Michigan Energy Code (ENERCODE, undated). Johnson (1976) referred to ASHRAE Standard 90-75 as "a complex technical standard." Even more complexity will be encountered as build- ing energy codes become more performance (vs. specification) (Olin gt_al, 1975) oriented which is considered desirable (Stein from Berry, 1975). According to comments by Carlson (1980) compliance with the Building Energy Performance Standards being developed (U.S. Dept. Energy, 1979) will be determined by one Of three computer programs selected for this purpose. Kusuda (1979a) attempted to develop a computer program with a simplified calculation procedure which still retains the capability to evaluate a building for compliance with sections 10, 11, and 12 of ASHRAE Standard 90-75. 15 3.5.2.3 load and energy analysis programs In a series of articles Chen (1975a, 1975b, 1976) discussed 12 com- puter programs dealing with the calculation of building heating and cooling loads and building energy consumption. His discussion includes not only the overall program capabilities, but also the various methods available for computing heat gain through building exterior walls and for determining cooling loads. He cited the possibility of a spread among loads calculated by various methods of as much as 80 percent. A compilation of programs undertaken by Crall (1975, 1976) resulted in a bibliography of programs pertaining to the area of heating, refrig- erating, air conditioning, and ventilating. Eighty-nine programs are included. Some of these deal with specific subjects outside the scope of this study. Thirty-four programs address the subjects of heating and/or cooling load determination, solar specialty programs, and building energy analysis. Romine (1976) discussed several programs available through the Automated Procedures for Engineering Consultants, Inc. (APEC) organiza- tion.- Included, and of particular interest to this study, are a heating and cooling load calculation program (HCC-III) and a program for deter- mining compliance with section 4 of ASHRAE Standard 90-75 (STD90). 3.5.2.4 auditing programs Several computer programs exist in the general area Of energy auditing of buildings. Buffington (1975a) developed computer models for simulating the transient energy requirements for heating and cooling of 16 buildings and applied them to a residential building (Buffington, 1975b). Colliver gt_al, (1976) described the HOUSE program which uses the individ- ual characteristics of a house, its inhabitants, and its location to estimate the total and dynamic energy usage. Another computer program entitled HOUSE was developed by Bodman §t_gl, (1979) to assist home owners in evaluating various energy conservation techniques of their own home. This program emphasizes energy conservation through good manage- ment. A home insulation analysis program developed by Hinkle gt_al, (1979a) and Hinkle gt_al, (1979b) estimates winter heating costs for homes in the northern and central parts of the United States. To pro- vide home owners with an evaluation of the economics Of additional insul- ation, program CHEAP was developed by Fehr gt_al, (1979). HACC is a program created by Bowen §t_gl, (1979) to provide interested citizens with energy and economic analysis of their home which could help them make well informed energy decisions. The state of Ohio has developed a computerized Home Energy Analysis audit which features a simple question- naire yet provides a comprehensive and easy to understand analysis report (Ventresca, 1979). One version of the Ohio computerized audit, the mini audit, features an input information form not requiring any dwelling dimensions, as the area of the home is estimated by the computer. 3.5.2.5. the IBUC_prggram The IBUC (In the Bank or Up the Chimney) computer program, analyzing weather proofing the home, was developed by Harsh et a1. (1976) and is based on a publication by the U.S. Dept. Housing and Urban Development 17 (1975). IBUC analyzes six energy conserving actions with respect to their potential savings if implemented, their estimated cost to imple- ment, and the amount of time to pay off the initial investment. The program is available on the Michigan State University Cooperative Exten- sion Service TELPLAN system described by Harsh and Black (1971), Bakker- Arkema and Black (1974), Brook and Bakker-Arkema (1978), and Harsh (1978). IBUC is discussed in detail in a later section. 3.5.2.6 the TRNSYS program TRNSYS (Transient System Simulation) is a computer program that utilizes a modular structural programming concept enabling it to model a variety of solar and building components. Instructions for the use of TRNSYS has been given by Klein gt_al. (1974). The user selects from a model library the component models corresponding to the components of the system to be simulated, specifies the manner in which they are inter- connected, and supplies the design parameters required by each component subroutine. Available component models include those normally associated with an active solar energy collection system, such as collectors, storage tanks, and controls and those simulating the dynamic heat flow through the walls, roof and floor Of a building. System variations are created by adding or rearranging components. The versatility of the TRNSYS program has been demonstrated by Klein gt_3l: (1975) in the simulation of a home space heating system with both solar and conventional energy inputs. One of the results indicated is that there is little difference in system performance between parallel and series arrangements of the auxiliary and solar heat units with the 18 load. Also, the inclusion of a heat exchanger between the collector and storage tank results in an eight percent reduction in heating by solar energy for the year. The feasibility of heating water for use in the food processing industry with solar energy was studied by Thomas (1977) using the TRNSYS program. In general, the simulation results indicated that solar water heating was economically feasible for food processing plants especially when electricity was the auxiliary water heating energy source being replaced by solar. TRNSYS is included in the bibliography of computer programs developed by Crall (1976) in the category of solar programs also described as specialty building energy analysis programs. The TRNSYS program was selected as one of three computer programs suited for de ermining com- pliance with the Building Energy Performance Standards (Whalon, 1980). 3.5.2.7 the NBSLD prggram The NBSLD (National Bureau of Standards Load Determination) program is the third program to be discussed in detail. Kusuda (1976a) described most of the subroutines incorporated into NBSLD and provided instructions for its use. The approach to load determination used in NBSLD is the most rigor- ous of the three programs discussed and employs the methodology recom- mended by the ASHRAE task group on energy requirements discussed by Kusuda (1976b) and reviewed in a series of papers by Chen (1975a, 1975b, 1976). 19 The capabilities of the NBSLD program have been applied in several instances. NBSLD was used by the National Concrete Masonry Association (1976) to evaluate the effect of heat storage in building components on the building heating and cooling load and thus the capacity of heating and cooling equipment needed. Burch §t_al: (1975) performed a valida- tion study Of NBSLD using an instrumented woodframed four bedroom town- house operated in a manner simulating occupancy and fluctuating climatic conditions. The test house was located in an environmental laboratory where winter and summer conditions were created like those occurring in Kalamazoo, Michigan and Macon, Georgia. It was found that NBSLD pre- dicted maximum loads averaging 3.2 percent higher than measured and pre- dicted energy requirements averaging 1.5 percent lower than measured values. Jones and Hendrix (1976) employed NBSLD to Obtain information on energy conservation opportunities that encourage more energy efficient Operation of homes in the Austin, Texas area. 3.5.3 Program sources There are four sources of computer programs addressing various aspects of energy according to Romine (1976). These include the educa- tional community, computer manufacturers and networks, equipments manu- facturers or trade associations, and engineering firms. Programs developed by each of these sources have both positive and negative char- acteristics in terms of quality and availability. Generally, the pro- grams developed by the education community are more easily obtained than programs developed by other sources. 20 3.5.4 Commuter access networks The need to provide information on improving the energy performance of homes to individuals in the RBC is supported by several authors. Petersen (1974) pointed out the need for home owners and home buyers to have access to this information for these individuals will be the ones to demand more energy conservation in the housing market. According to Colliver gt_al, (1976) residential dwellers do not have sufficient infor- mation concerning the possibilities of energy conservation in their homes and, therefore, are not utilizing existing technology (energy con-. servation) to its full potential. One approach discussed by Black and Coad (1976), that is suitable for extending computer capability to smaller organizations is that of the shared-time computer network. Using a purchased or leased communi- cating terminal and an ordinary telephone, communication access to high capacity computing equipment can be obtained. A number of world wide shared-time networks are available including TELENET, MERIT and INFONET (Kusuda, 1976). The National Association of Home Builders (NAHB) uses a computer access network to permit home builders, subcontractors, and associated organizations to access NAHB's Automated Management Informa- tion System (AMIS) (NAHB, undated). Currently this network does not offer programs addressing energy/housing subjects. I A number of universities have developed computer access networks through their Agricultural Extension Service programs and are currently offering an energy/housing program, among others, to their users. The HOUSE program (Bodman g§_al,, 1979) is available through the University of Nebraska AGNET (AGricultural computer NETwork) system (Kendrick §t_al,, 21 1976). The Virginia Polytechnic Institute and State University Offers the HACC program (Bowen et_al,, 1979) through the Computer Management Network (CMN). A home insulation analysis program is available on the FACTS (Fast Agricultural Communications Terminal System) network of the Indiana Cooperative Extension Service (Hinkle et_gl:, 1979a and Hinkle gt_al,, 1979b). The IBUC (In the Bank or Up the Chimney) program developed by Harsh et_al,, (1976) is available on Michigan State Univer- sity's TELPLAN system. Another way of making computerized energy/housing programs avail- able is to mail or distribute input forms to potential users. Based on the returned information the computer analysis is performed and the results mail returned to the home owner. The CHEAP (Computerized Home Energy Analysis Program) program is administered in this manner in order to provide the service to more people (Fehr §t_al:, 1977 and Fehr et_al,, ,1979) although it is also available through terminal access. Both postal services and portable computer terminals are used by the Ohio Department of Energy to make their Home Energy Analysis residential audit available to home owners (Ventresca, 1979). Mail out-return methods of computerized energy audits and analysis have not had good response rates. Ventresca (1979) indicated a return rate of 10 to 20 percent for the 29 question format of Project Conserve. Bowet gt_al, (1979) indicated a four percent return rate on a free offering of home energy analysis by the Virginia State Energy Office and Virginia Cooperative Extension Service. Bowen gt_al, (1979) sug- gested a lack of motivation to complete the input form as the reason for the poor response rate. 22 3.5.5 Prpper application of compgter capability The computer program and the computer program user are both impor- tant factors in successfully attaining creditable information to help in making decisions on enerQY/housing matters. Proper program selection and application can provide beneficial results, but misuse or improper application of programs can also occur. In a comparison of several pro- grams Spielvogel (1977) found that the degree of agreement between programs depended on the interpretive ability of the user and on the suitability of the program for the particular building being studied. Ventresca (1979) referred to the importance of selecting a computer pro- gram using methodologies appropriate for home energy auditing purposes as opposed to using a program using complex methodologies for auditing and requiring large amounts of detailed input information. In a dis- cussion on the appropriateness of various programs, Black (1977) com- mented that the output from a complex program Obtained by a user not understanding the purpose or methodology of the program can give the user an impression of knowledge that does not exist. 4. APPROACH TO THIS STUDY The computer is well established as an appropriate tool for appli- _cation to tasks involving repetitive, lengthy, time consuming, and incon- venient mathematical and manipulative operations. This makes the computer well suited for application to situations addressing building energy performance. From the many programs in existence three were selected for this study which represent the range in techniques used to evaluate the var- ious aspects of building energy performance. The three selected are: (1) In the Bank or Up the Chimney (IBUC), (2) TRNsient SYstem Simula- tion (TRNSYS), and (3) National Bureau of Standards Load Determination (NBSLD) program. The IBUC program is available on the Michigan State University Cooperative Extension Service TELPLAN system. IBUC employs a steady state load calculation methodology and a degree day energy consumption methodology, applied to the energy auditing of homes. The TRNSYS program is available on the Michigan State University central computer since it was used previously for the simulation of solar water heating systems for commercial application (Thomas, 1977). This program represents both steady state and dynamic approaches to building energy performance. TRNSYS uses a unique approach to system simulation in that the user creates the system to be simulated from a library of available component simulation subroutines. 23 24 The NBSLD computer program was not available at Michigan State University prior to this study. A NBSLD program manual was obtained and from the program listing a punched card deck was created. Some modifi- cations Of the program were necessary to make it compatible with the Michigan State University central computer facility. In addition to the modifications, some debugging of NBSLD was required before correct out- put could be achieved. The NBSLD program offers several options in both steady state and dynamic energy load determinations of buildings. The discussion which follows is a comparison of the IBUC, TRNSYS, and NBSLD computer programs in terms of: (1) input format and type of information required, (2) heat transfer methodology used, (3) output format and type of information produced, and (4) general operating char- acteristics of each program. Neither a validation of the programs nor a comparison of program output values is intended. The intent is that through the discussion, a better understanding of the characteristics of typical energy/housing programs can be gained. With a good understanding of typical programs one can better assess other existing programs and select and use the program appropriate to achieve the desired Objective. Many program runs were made in exploring the characteristics of the three computer programs. Each program was applied to a residential building of single level ranch design with a natural gas forced air heating system. Since the purpose was to explore the characteristics Of the programs, input information describing the example house was varied from run to run. Examples Of the kind of changes made in the input are: (l) heating and cooling situations, (2) with and without 25 windows, (3) constant and changing weather conditions, (4) flat and sloped roof surfaces, and (5) with and without basements. Because of the variety of input information the examples of program input and out- put appearing in figures and tables which follow will vary from example to example. The figures and tables were selected to illustrate a pro- gram's features rather than to compare output values with a particular residence which had had its energy performance documented. Following the discussion of the three programs a plan is proposed for making computer programs, addressing building energy performance, accessible to potential users in the residential building community. By doing this the computer becomes a tool which the residential building community can use to easily gain information necessary for making well informed decisions related to building energy performance. The plan is based on an assessment of the composition of the residential building community and of the current state of computer capability in the resi- dential building community. A proposal is made on how the use of com- puters can be expanded to provide computer capability services to the residential building community. 5. THE IBUC PROGRAM 5.1 The Purpose Of IBUC In the Bank or Up the Chimney (IBUC) (Harsh gt_§l,, 1976) is a computer program adopted from a manual of the same title (U.S. Dept. Housing and Urban Development, 1975), prepared for the United States Dept. Of Housing and Urban Development (HUD) by Abt Associates, Inc., Cambridge, Massachusetts. The HUD publication is intended for use by a home owner and has two objectives: (1) to assist in making the best choice of energy saving home improvements and (2) to provide step-by- step information on the correct installation of the improvements. The computer program adopted from the HUD manual deals only with the first Objective. Use of the IBUC program enables the home owner to easily gain the economic information needed on which the correct choice of energy saving home improvement decision is based. Through either the HUD manual or the computer program, users are made aware of the potential economic impact of various energy conserving actions. The IBUC program eliminates all manual calculations and simplifies the required input information on the part of the home owner, thus encouraging his participation. Examples of input and output for the IBUC computer program are shown in Table 5.1 and Figure 5.1 respectively. The information pre- sented is used to illustrate the features of IBUC, discussed in the following sections. 26 27 Table 5.1 Input values to the IBUC computer program describing the example residence. See Appendix B for a completed IBUC input form using these same values. Section I General Information 1a. 3, b. 14, c. 3, d. 1, e. 1620, f. l, g. 0 2a. *, b. *, c. *, d. *, e. *, f. * Section II Caulking and Weatherproofing Doors and Windows 3a. 2, b. 14, c. 2 4a. 2, b. 2, c. i4, d. 2 Section III Storm Window Information 5a. 3, b. 12 Section IV Attic Insulation 6a. 1, b. 3, c. 0, d. l, e. 0, f. 0, g. 0 7. 42, 24 8. 16, 32 9. 10, 10 (10-26 not applicable) Section V Wall Insulation Information 27a. 164, b. 0, c. 0 28a. 0, b. O, c. 2 Section VI Crawl Space Walls, Floors, and Basement Wall Information 29. 0 29a. 1, b. 0, c. 1, d. 0 30a. 110 (31-34 not applicable) 35a. 4, b. 58 Section VII Changing Thermostat Setting 36a. 973, b. 4 (37 not applicable) 38. O (completes input information) 28 5.2 Input to IBUC The input information for the IBUC program describes the physical characteristics of the residence including the basic dimensions, the number of windows and doors, and the style of architecture. Information describing the extent to which some energy saving actions have already been employed and their current physical condition is also requested. Such items as weatherstripping, caulking and amount of insulation are included. Other inputs requested include the type of fuel and the indoor thermostat setting (although not used in determining space load require- ments). A complete input form for the IBUC program is included in Appendix B. Table 5.1 is an example of typical input information needed for the IBUC program. For the house in this example, input information is needed for all six (sections II-VII) of the energy saving options avail- able in the IBUC program. .Section I is a general information category. The values in Table 5.1 are the same as the values shown in the IBUC input form included in Appendix B. The amount of descriptive information required varies depending on the users' choice from among six options pertaining to energy conserving actions. The options are: (1) caulking and weatherstripping, (2) storm windows, (3) attic insulation, (4) wall insulation, (5) crawl space/ basement wall insulation or floor insulation, and (6) thermostat adjust- ment. Any number of these may be selected depending on the users‘ needs and interests. Using all six options the example required 51 items of input. As few as 10 input items are needed if only one of the Options is desired. Regardless of the options selected, supplying the information 29 is not a demanding task as the input items require responses in the form of either checked choices (section I), numerical quantities, or basic structural dimensions. A number of illustrations are used to aid in the user's understanding of the information requested by particular input items (see input form in Appendix B). 5.3 Output from IBUC Output from the IBUC program, a result of the input information in Table 5.1, is shown in Figure 5.1. The output consists of economic information on each of the six energy conserving options. Some of the six options are broken down into two energy conserving actions with economic information output for each one. Option one, the caulking and weatherstripping option, is divided into two economic outputs. One regarding caulking doors and windows, the other regarding weather- stripping doors and windows. The output from each energy conserving action contains three items of economic information: (1) estimated dollar savings realized the first year as a result of implementing the energy saving option, (2) estimated investment to implement the option, and (3) estimated number of years to pay back for the Option. The home owner can use this economic informa- tion to choose the energy conserving action he wishes to implement. The decision may be based on pay-back period alone or it may be based on the finances available for improving the energy performance of the home. Estimated dollar savings is simply the change in the thermal per- formance of the home, expressed in monetary terms, resulting from the energy conserving action. This enables the home owner to compare 3O 06..- In THE game q; Up THE CHIMNEY o... q coneursp cagg=qm To RNGLTZE MEQTHEP EDDDFING THE HUME =qmruv LIVING EDUCHTTUH CUUDEPQTIVE EETENEIGN TEPVICE urcurgau :Tqrg Uwrwsegrrv .3. ORDERING amp MEATHEPETPIPPING DEEP: 9ND mrnDOm: ... 1; IRVING? EEDM CHDLRINE DDDPE END MINDDm: us/rew a 4. TUTQL INSTRLLRTTUN ED:T a 6 ED. 94T633CK PERIOD 4???? s 4.3 a. savrwes =90” weeruevsrereerwe Dope: END MTHDDm: of You = II. TUTRL IHETRELRTIDN COST = s 40. Per—BREE PERIOD (v93: 1 3.2 ... STQPM MINDCM ThsTaLEnTIDN ... 3; sevrwe: FROM ETDPM MINDBM INDTREEETTDH narrow a 57; TOTeE INETaLLPTIDn BUTT 2 6 420. Par-sack PERIOD ever» a - 3.3 ..e ATTIC INEDLRTIDN ... 4; ERVING: FQUM TNEULRTING 9 UNFIHISHED RTTIC TDTBE RODEO anuuec TNETELaTIDn eeraecw PEPDID INCHES INCHES sevrnstsn COSTfflY rEePs 4 I.O 26. tar; 4.0 5 3:0 5?. "300. 4.4 a 5.0 PO. 473. 3.4 to 2.0 Pa; 656. 6.4 IE 9.6 as. 334; 7.3 T4 II.O 67; I012. 3.1 .5. wet: TNEuEaTrOn ... .; Equues Peon rnsuuerrne HEEL: (6 res 2 III. TDTaE INETELEETIDN CDET a s 656. PRYancw PERIOD {3933 i 4;? ‘NDTEo 44 a chrnchDP MILL NEED TO DO Tar: JOE “° UBBMC 39968; UNDER EEODes; ewD serEnenT MALL: Iwzuterrow ... e. SBVING? Ewan INSULJTTNG Doom; :PECE rsxrew = 49. TDTEL INETaLEeTIDN CDET . s 205. Par-Dace PEEIDD (W93? 2 3.? IO; sevrwos EPOM TNIDERTTNE BREEMENT mutt: iE/TQT a 46. TDTJE r~ETELEnTIO~ CD:T 2 6 I30. Paw-gnaw ngrgn recsv s 3,5 .66 THEOMUETQT ADJUSTMENT .9. TI; SQUINGZ EPDM THEPMCTTQT Teen-Down tsrvcw = I13. Figure 5.1 Output from the IBUC computer program showing the estimated dollar savings for the example residence. 31 various energy conserving actions, or several stages of implementation of one particular energy conserving action, on the basis of energy saved each year, valued in dollars. The Option indicating the most savings in Figure 5.1 is thermostat set back. One hundred thirteen dollars is expected to be saved as the result of a four degree (input 36 b) lowering in thermostat setting. A savings of one hundred eleven dollars is estimated from insulating the house walls. The least amount of savings expected is from caulking the fourteen doors and windows. Only four dollars a year is expected from this energy saving Option. Input information (input 3 a) indicated the present condition of door and window caulking to be fair. Estimated investment is the second item Of economic information output for each energy conserving action. This value is selected by the computer from a stored file of costs assigned to the various thermal improvements. Periodic updating of the cost file is necessary if the economic output is to reflect current construction material prices. Even then improvements costs may not reflect user local conditions because local costs may vary from the average costs in the data file. The most expensive thermal improvements shown in Figure 5.1 are ceiling and wall insulation. If seven inches are added to the existing three inches (input 6 b), the cost is estimated to be six hundred fifty- six dollars. If nine or 11 more inches are added the costs are expected to be eight hundred thirty-four and one thousand twelve dollars respec- tively. Wall insulation is estimated to also cost six hundred fifty-six dollars. The least expensive energy conserving action is thermostat turn-down at no cost. Immediate savings are realized from this energy saving action. 32 Estimated years to pay back is the third output item of economic information. Years to pay back is the estimated investment divided by the estimated savings per year after the estimated yearly savings has been adjusted to reflect its present value. The years to pay back in Figure 5.1 range from a low of 3.2 years for weatherstripping to a high of 8.1 for 11 additional inches Of ceiling insulation. 5.4 IBUC Methodology In both the HUD manual and IBUC computer program, the output obtained is a result of the selection and mathematical manipulation of predetermined values. The IBUC program alleviates the user's task of making the selection Of the appropriate predetermined values, based on user input information, and of performing the necessary arithmatic cal- culations. In the use of predetermined values in IBUC a sacrifice in accuracy may be made since the predetermined values may collectively represent many factors which vary with the individual dwelling and dwelling location. Any discrepancy between predetermined values in the IBUC program and conditions representing the user's situation can result in output that does not reflect the user's actual situation. The derivation of the predetermined values used in the IBUC program and their effect on program output is discussed in the sections which follow. The sequence of their use in arriving at the output information, their names as used in the HUD manual, and the parameters contributing to the values are depicted in Figure 5.2. 33 mwz~>4m omh 66 x EHQQ x P x w x .HE .38 x .m: x >wgmzu ozfiemzzh m_asmxm one E05 :o_umEEo5:_ H:Q:_ szuu< «.6 mezmwu oo+mooo._ oo+mooo._ oo+mooo._ _o+6655._- co+uooo.o .o o .o oo+uooo._ Penmcmm.m oH mm o m .NP _ whamzm ach6 v5 .o .o .o 5 .6 o .o o .o e mpzazm Fo+mo~_.m No+momm.m oo+mooo.m w mmuhmzh NF oo+mooo.5 oo+mooo.— Po+mooo.P m. mmmhmzh 6 ozu 6H2: 6H2: kHz: kHz: 56 The user needs only to incorporate print and/or plot modules into the program and to identify the source module outputting the desired infor- mation. In general, the print and plot modules are utilized in the same manner as other TRNSYS library modules with certain requirements peculiar to the functions they perform. The form in which the output appears is determined by the printer module. The time interval at which output occurs is user specified. An output for the degree-hour simulation program of Figure 6.3 and 6.4 is shown in Figure 6.5. From Figure 6.3 the desired output sources are. identified by noting the UNIT number and the output position number. The output sources the the ambient air temperature (9,7) the heating load (12,3) and the cumulative heating load throughout the simulation period (24,1). These sources become the input to the printer module (UNIT 25, TYPE 25) with the resulting program output shown in Figure 6.5. Auto- matically included in column one of the output is the time of printout, the printout interval having been specified by the user in the printer module parameter list. The TRNSYS output of Figure 6.5 is for a simulation period of 24 hours in mid January. The second column is the hourly ambient tempera- ture output directly from the weather data tape. The third and fourth columns are the hourly and cumulative heating loads respectively. The greatest hourly load (6,656 KJ/HR-°C) for the example house occurred the initial hour of the simulation. The smallest load (5,381 KJ/HR-°C) occurred 19 hours into the simulation during the warmest (0°C) hourly outdoor temperature. The methodology of the energy per degree—hour module (TYPE 12) used to simulate the house in this example is discussed in section 6.5.1. 57 TIME Tamb HQLOAD TQLOAD 1104.0000-5.001E+OO 6.656E+03 O. 1105.0000-4.835E+00 6.613E+03 6.635E+O3 1106.0000-4.612E+00 6.557E+O3 1.322E+O4 1107.0000-4.446E+OO 6.514E+O3 1.975E+O4 1108.0000-4.057E+00 6.415E+03 2.622E+O4 llO9.0000-3.723E+OO 6.33OE+03 3.259E+04 lll0.0000-3.334E+OO 6.231E+03 3.887E+O4 1111.0000-3.l68E+00 6.188E+O3 4.508E+O4 1112.0000-2.945E+00 6.132E+03 5.124E+O4 1113.0000-2.779E+OO 6.089E+O3 5.735E+04 1114.0000-2.057E+OO 5.905E+03 6.355E+O4 1115.0000-1.279E+00 5.707E+03 6.915E+O4 lll6.0000-5.564E+01 6.522E+03 7.477E+04 lll7.0000-3.897E+Ol 5.480E+03 8.027E+O4 1118.0000-1.675E+01 5.423E+O3 8.572E+O4 lll9.0000-8.000E+04 5.381E+O3 9.112E+O4 1120.0000-5.564E+01 5.522E+O3 9.658E+O4 1121.0000-1.112E+OO 5.664E+O3 1.022E+05 1122.0000-1.668E+00 6.806E+O3 1.079E+05 1123.0000-1.501E+OO 5.763E+03 1.377E+05 1124.0000-1.279E+00 5.707E+03 1.194E+05 1125.0000-l.112E+OO 5.664E+O3 1.251E+05 1126.0000-1.112E+OO 5.664E+O3 1.308E+05 1127.0000-1.112E+00 5.664E+03 1.364E+05 1128.0000-1.112E+00 5.664E+03 1.421E+05 Figure 6.5 Output from the example TRNSYS program depicted in Figure 6.3. 58 The general characteristics of the TRNSYS library modules have been discussed and program formulation method has been illustrated using a simple application of the degree-hour (TYPE 12) module. While the exam- ple does serve the purpose of illustration, it by no means conveys the full extent to which the TRNSYS simulation system may be utilized. 6.3.2 TRNSYS prggram: modules TYPE 17, 18, and 19 TRNSYS modules TYPE 17, 18, and 19 account for more of the factors influencing the energy performance of a building than does the TRNSYS TYPE 12 module. The TYPE 12 module accounted for only one influencing factor, temperature difference, as the driving force in the heat trans- fer process. In addition to the air temperature difference, solar radia- tion, wind, and thermal capacitance are among the factors considered with respect to their influence on the total energy performance of the residence when TRNSYS modules l7, l8, and 19 are used. Modules TYPE 17, 18, and 19 are incorporated into the program, as it is formulated, in the same manner as any module would be if it represented a real compon- ent in a system involving the flow of energy. The simulation method- ology used in the TYPE 17, 18, and 19 subroutines is discussed in sec- tion 6.5.2. (The second example program, incorporating modules TYPE 17, 18, and 19, is illustrated in the block diagram shown in Figure 6.6. Twenty TRNSYS modules make up the simulation program. Of the 20, only seven carry different TYPE numbers since some are used repeatedly in order to give individual treatment to the building constructions of the home. 59 .mmpavos m>mzmh 6_ use .wp .5_ ma>p mgu 5o mmopouozums mg» 6:_m: Emgmoga mum—anu m we Emgmmwv xuo_a m—quxm c< 0.0 wL:6_6 duhz—xm an um>h wN buzz wflmfivh: ao—c o— mark an Fuzz ecu «us: a a a _ F l, T l 1 1.15 Mdouc aqua: a nu mark ue #62: ma mark an hmza uaoo no»: :30 30¢ a a, a .0 a a 3.3. .39. «a: .89. a 4.2: G ...—<3 2 .35. a ...: 3 2t. 2. :2: 2 9:... S 2.5 2 not. 3 .52: 2 at... an :2: 2 met an 3.5 2 BE 2 .52: H3 .30 Q R up- hl I h 33 Q .az: =2. hex; 1 l. r 71%. jiflfl 11 H 1 Oh In. 11 3’ a a = 95 ..s. was ..9. a... ...: a: ..5. 2. 8.. cm mark an buzz o~ mark «a has: on mark an baa: cg mark an Buzz cu umkh on bus: 2 = 60 The program begins with a TYPE 9 card reader module. This module accesses the weather tape which supplies hourly data on ambient temper- ature, wind velocity, and solar radiation, the major driving forces considered in the heat transfer processes. The solar radiation infor- mation from module TYPE 9 becomes input to eight TYPE 16 modules, the solar radiation processors. The solar radiation modules translate the radiation incident on a horizontal surface, as obtained from the weather data tape, to that incident on a wall or roof surface slope and orienta- tion. The translated solar information output from the solar radiation processors, TYPE 16, is supplied as input to the four TYPE 17 wall modules and the two TYPE 18 roof modules. A TYPE 17 wall module is used to predict independently the energy flow through each of the four walls of the example house. Each of the four TYPE 17 wall modules receive four inputs. The inputs are trans- lated solar information from the TYPE 16 module, wind velocity and ambient temperature input from module TYPE 9, and room temperature input from the room and basement module TYPE 19. The rate of energy transfer between a wall and the room is the output from each of the TYPE 17 wall modules used in the program. Those four energy flow rates are summed through use of a TYPE 15 algebraic operations module, yielding the total rate of energy flow through the walls of the residence. This quantity then becomes an input to the TYPE 19 module, the room and basement. Two TYPE 18 roof modules are used to model the rate of energy exchange through the roof/ceiling construction in this example. The example residence described in this program is one with roof ridges running in both the east-west and the north-south directions. This ' accounts for the roof surfaces facing four different directions. Each 61 of the two TYPE 18 roof modules account for the two opposite facing roof surfaces. Two solar radiation inputs from TYPE 16 modules are required by each of the TYPE 18 modules to account for the two opposite facing roof surfaces. Otherwise inputs to the TYPE 18 roof module are the same as for the TYPE 17 wall modules. The outputs from the two TYPE 18 roof modules are the rate of energy flow between the ceiling and the room. These two outputs are summed through use of a TYPE 15 alge- braic Operations module before becoming input to the TYPE 19 room and basement module. TYPE 19, the room and basement subroutine is a major module in the TYPE 17, 18, and 19 method of simulating the thermal performance of a residence in the TRNSYS system. The TYPE 19 module receives the output of TYPE 17 and 18 modules and incorporates this information, along with other inputs and parameters, into an algorithm leading to a determination of the thermal performance of a residence. A provision is made in the TYPE 19 module to account for a variety of user specified sources of heat gains or losses other than through the ceiling/roof and wall building constructions. The example program (Figure 6.6) indicates that three inputs are made to TYPE 19. They are the rate of energy flow between the room and the ceiling, the rate of energy flow between the room and the walls, and the ambient temperature from module TYPE 9. A TYPE 25 printer module is used to gain output from the example program. This concludes the formulation of the TYPE 17, 18, and 19 program for the simulation of the example house. All of the input for the TYPE 17, 18, and 19 program is shown in Figure 6.7. The values shown are an accumulation of the information requirements of the eight categories for each of the 20 TRNSYS modules. 62 .8.8 8886.6 8. 8888.888 58868.8 m>mzm. an. .8. 88.88sgowc. .888. 5.8 8.86.6 5.58.5 3.58.— .o n mu>=«=u.8 .8 .o .8 8 ea 5 .8. o .8 . 8n 5 .8 1.... 88.8 3. c 2...... ~ 8. . .8. . ... 8.88.8 8-888 .8 .8-88.. 8.88... 8.88.. . a .52.. 8 .5532. 8.88 8 8.88... 3.88... 8.88.. 5! 8 2 8:. 8 :5 . 9.8;. 8.88.. 8.88.. .8 5.2! an r». 5. :5 _ n 3:525: 38 .8 .8 .8 .8 :8 lb ..«8 .88. .58. 58 g g It. 5 .8. 8 .o . .8. 8 .8 . . . . . . . . .3 . 8.8... . 8 . 8 . 2 . ... 8 .n . a u 8. . .8. . .8 .8-88... 8.88.8 .8 8.88.. 6.88.8 8.88.. . . 8. .58... 8 2.8.8:: 8.8 8 8.88. . 8.88... 8.88.. .3! 8 .. 8.. 2 ...... c .553: .8 . 5.2! . an at. 86 ...! 8... . 8 . 8 ..8 . 28.... . .8 . a. . 8 .8 8.8.8.. 8.88.8 8.89.. 8.888.. 8.88.. 8.88.. . . 8 Ex... . 8883.: 8.88 ~ 8.88 . 8.88.... 8.888.. ...-a I 8. 8. 8.. n. ...s 8.88.. 8.83.. 8.88.. 8.88.. 8.88.. .8 8.88.8 8.88.... 8.88.. 8 n. «this... 8... . 588.3. .8. .8. 8.. 8. ...: . .88... . .8... . .8». . .88 . ..... .8 8.88... 8.88.. 8.88.8 8.88.. 8.888.. . mung.“ . . . . . . . . . 888. 8 8888. 8 8.888 8. 2g” .5... 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The user may obtain output from any TRNSYS subroutine by specifying the output source in the TYPE 25 printer module. (The output of Figure 6.8 is for a simulation of the example house for a period of 24 hours in I mid-January. The six outputs in Figure 6.8 are (first row) ambient temperature, heat loss through the north-south roof, attic temperature of the north-south roof, (second roof) hourly heat loss through the house walls, hourly house heating load and indoor temperature. In this simulation the indoor temperature is allowed to drift between maximum and minimum specified values. As long as the calculated indoor temperature is within the specified limits there is no heating load. This situation can be seen (Figure 6.8) during the first six hours of the simulation. At the start of the simulation indoor temperature was 21 degrees, midway between the maximum and minimum specified values. Since the minimum temperature is satisfied for the first six hours of simulation there is no need for any heating. Gradually the indoor temper- ature falls to the minimum value specified (l8.3 degrees) and heating of the house is necessary beginning the seventh hour of the simulation. The minimum indoor temperature is maintained throughout the rest of the simulation period. The maximum house heating load (l5,880 KJ/HR) is during the eighth hour of the simulation. At this time the heat loss through the walls of the house was 7,328 KJ/HR or 46 percent of the total heating load. 64 TANS NSR QLOAD RTEMP :lqflfllhylmrlnlllllzlllllalflltlfllfl1319lfllulOlUllel ..rLC. LC?Caracrtnxir..-.Cref:.T.. mfg:.09.”:9...»CCUCOCLCConcrcoaunzkCCU... .+++++.+.+.+.+.+.o.+.+.++++9¢+++++¢++++++++++¢++++ Er-.L—LEPEPEEFFEEEr.EEEEEFEEEFEr.r.:tEEEEE[EEEEEFEEEEEFEE 69.8511571524CL30605012L604G1.09.3.UL651.U5059202:u35652€ 3:07;. a Q.343C2€.237.3333314.36353,n.3231383135373332331...» 373 51.50.Lc.rda,...10,20....q,89.m8.l“dncp,78c487Qua/H.18nuocfiusq 8,68:JD..R7.?58.30.4P44R. o000.000.0000...0000.00.00.00.00.000000.00.0.0000. D.21211.6.19181515131914 1.91111121£121.11...11111....1111111 . . . . . . . . u . 1 . J 7 . .9. K . . . . . . . - . 1 . n... b. n; 1. G n... firsts—L L...Ce..0r.\.u CruLCfitb n....ULnU...C¢..r.P.P 0r... CCQALCOrJ. + + ... + .o + ...v+++++++++++++++++¢++++++++++++++++++ r. F. E E r. .L r.Er.F.EFEEFmEr.E.LEr.r.::t:t.—Lr.r.EF.LrLr~EEEp._t.r.fur.—p2r_r. ad 7. a: Q 7 b. 79th.”..- .5927. rad—327....-. C1». 370-}91481.OQ.4L .43 Eac4971.3/..41;3 .L 7 1.. 5 2 D. 7548371579.24620.35532233559799999.0.99C. 09 a 3 U 9 9 Q 9:31.316c12r.,U»JZQ..18282F.1qF“GHQLOANRO 014s64$.48.494 oneocooooooo.ooooo0.000...oooooooooooooooooooo-ooo 3n. 3.923101313112 $9.12121211...1.11111111111111111111.111 .................. ........... ... ... .. .. no . . 7 at. .UJG. .- . f7 . 1 1. 1 1 .U-. r» .L 9 O. r. 0.. .... OUCAUL pr.U.i.. .vaUAur-ucn..U»...Urxunxgor.va.ucpl.ru. 95679.9.UGOuAU.UfiUn.AUflLCPUPvP3UP..B.LGPUC ++§++++++++++++++++++++O....-+.§.+.¢+§+++++§++++++9+ ...—truthfurr.r.EF.Ef.ur—LEC FELL.EEF.—LEELFf_r_r.f,2tr.F.r.mr.F.F_FLEpLE—L...»:Crtt pLEErLE 9.75731062782902427?_SSR\C5C72HVE27DU80(6800120-(957830.030005 910 Q Balkan/54.11.124.321“. 65R.46614:47749_ U246 btu—H.4r0564n...3.L:J:U6L O a» 99.1. 6291»: 9.7735113 9.76872546785229451061412111111111 coo ocooooooooooooooooooso...oooooooooooooooooooo “at“ 04.3 14 C47 37 3737054239.21h.53341:u1:4:..617171717.17171717 .... .n..........-.....- 00 quGOGOQDG uCUOWGCCCCOD. .03 uCL uGCGOOCUG uCUCOfiCCGOOO PC3OCCCUDOSCOCCGGOGCUGOfCCGCLOGUOOOCOCU0uLOCPDCOOG CC. .rv.L»......LC£.LCfiCn. CCn EC CCOC r..uf.9n.rxfrufi.9..ufr ...r. Cr.57:12:»...(Eff. 0000000...00000000000000o000.00.000000000000000... 44556677989900112233“.45.355778899001122334455457789 ...306.3333COUCIIL11.11111111.11.111.1122222222222222.4222 1111111111111111111111111111111111111111111.1111111 111111111111111111111.11111111111111111.111111111.1.11. Figure 6.8 Output from the TRNSYS program depicted in Figure 6.6. 65 6.4 TRNSYS Methodology The discussion of heat transfer methodology is limited to those TRNSYS library modules that pertain specifically to the simulation of the thermal performance of a building. Basically, there are two methods a TRNSYS system user may employ to simulate the energy performance of a residence. One method is relatively simple while the other method is more complex. The more complex method describes the heat transfer pro- cesses in greater detail, thus more closely representing the actual heat transfer situation in a building. Both are available through the flex- ible programming provision of the TRNSYS simulation system. The method employed depends on the needs, priorities and objectives of the TRNSYS system user. 6.4.1 TRNSYS module TYPE l2 The primary module from the TRNSYS library that achieves the degree- hour simulation of the heating load of a residence is the TYPE l2 sub- routine. This module utilizes an approach similar to the degree-day concept for estimating the heating load of a residence. Degree-day values are not used by TRNSYS. Instead, an energy per degree-hour method is used. The equation for the instantaneous heat load, as used in TRNSYS module TYPE l2 is: 66 QL = UA (Tr - Tamb) = Qgen - anin where QL instantaneous residence heating load, energy/hour UA user determined residence heating requirements, energy/degree-hour Tr = residence room temperature, degrees Tamb Qgen outdoor ambient temperature, degrees constant heat gains (appliances, lighting, people), energy/hour anin = time variant heat gains to the residence, energy/hour The most significant aspect of the TRNSYS degree-hour method is the basis for obtaining the driving force temperature differential, T T is user specified, Tamb is taken from hourly climatic r ' Tamb' r records for the geographic location in which the residence is located. This provides an hourly accounting of the required energy load rather than a monthly or yearly estimate as when the degree-day concept is used. With the degree-day concept the driving force is based on an accumula- tion of degrees of temperature difference between the mean daily tempera- ture and 65 degrees F.. Four mode options are available to the user within the TYPE l2 module. These options provide programming flexibility in that one of the options will describe the users existing system. If no real system exists, there are four system options available for experimentation. Two of the options deal with situations where two sources, auxil- iary and solar for example, may both contribute to satisfy the Space heating load. In one case the auxiliary source supplies the entire load 67 when the solar supply is inadequate to satisfy the entire load. In the other option the auxiliary source makes up only that part of the total load that the solar source is unable to fulfill. In both of these cases the space load is a function of the user specified room temperature and the heating requirements of the residence. No auxiliary energy source is included in either the third or fourth mode option of TRNSYS module TYPE l2. The third option is strictly a space load determination on the basis of the user specified room temperature and the residence energy requirements. Application of the mode three option of TYPE l2 to the example residence is illustrated in Figure 6.3, 6.4, and 6.5 in the discussion of program formulation. In the fourth option of module TYPE l2 no room temperature is specified. Instead the thermal capacitance of the residence is specified. The resi- dence capacitance and the residence energy requirements then become the basis for determining the residence room temperature. 6.4.2 TRNSYS modules TYPE l7, l8, and 19 6.4.2.l TYPE l7 wall Each exterior wall of a dwelling may be modeled independently using module TYPE 17 of the TRNSYS library. Variations in each wall building construction may be described and, thereby, taken into account with respect to their effect on the thermal performance of the building. Typical information required to describe each wall includes the wall area, the percent of wall area that is window, the percent of window that is shaded, the absorptance of the wall to solar radiation and the 68 infrared emittance of the wall. Weather factors such as solar radia- tion, wind velocity and ambient air temperature are inputs to TYPE 17 from weather data. The user has the option of choosing between one of three standard wall constructions or specifying a wall construction composed of his own selection of materials. The latter option requires a thorough under- standing of the principles of heat transfer by the TRNSYS user. The three standard wall construction options are an insulated wood frame construction, an uninsulated masonry construction, and a combination wood frame with face masonry insulated construction. All of the material dimensions and thermal properties of the walls have been included in the TYPE l7 subroutine. Both differential and algebraic equations are used to describe the flow of heat through a wall construction in the TRNSYS TYPE l7 module. Algebraic equations are used to describe the flow at the outside surface node since this node is assumed to have no thermal capacitance. Three additional nodes within the opaque portion of the standard wall construc- tions are described with differential equations. These equations account for the thermal capacitance of the wall construction materials. Since derivatives are used the user must provide the TYPE l7 module with an approximate value for the initial temperature of each of the three internal wall nodes. The number of derivatives and the approximate initial temperature values are specified in information category seven and eight of the input for a TYPE l7 wall module. Conduction and radiation are the two means of heat transfer con- sidered in the TYPE l7 module. Conduction through the opaque portion of the wall and conduction through the windows are both considered, but 69 are accounted for through separate calculations. Heat gain as a result of solar radiation through window glass is the other source of heat flow considered. Total heat flow through the wall construction is the sum of the heat flow by the way of the two conduction paths and the heat flow by the way of the radiation path through the window portion of the wall. 6.4.2.2 TYPE 18 roof The TYPE l8 roof subroutine serves the same purpose in a TRNSYS pro- gram as the TYPE l7 wall module except the roof subroutine deals with heat flow through the roof/ceiling constructions. In the case of both the TYPE l7 and the TYPE l8 modules the total heat exchange between the room and the building constructions becomes input to the TYPE l9 room and basement module. The TYPE 19 module uses this information to describe the total thermal performance of the building under study. The user may select from several standard roof constructions avail- able in the TYPE l8 module. The properties of the standard construction are completely Specified within the module. The user also has the option to specify a construction composed of his own selections of building materials. The standard Options include a flat roof, with a two or three node option, and a pitched roof with or without solar collectors mounted on it. Some of the parameters that are provided by the user to the TYPE l8 module that are used to describe a typical roof/ceiling construction include the ceiling area, the areas of the roof surfaces facing different directions roof absorptance to solar radiation, and infrared emittance of 70 the roof surface. The flow of heat through the roof/ceiling assembly is described using both algebraic and differential equations. 6.4.2.3 TYPE l9 room and basement TYPE l9, the room and basement subroutine, incorporates the inputs from the TYPE l7 and the TYPE l8 modules and other sources into an over- all dwelling space heating or cooling load simulation. In addition to the load contributions from the heat flow through the ceiling and walls the contributions due to infiltration, basement construction and internal heat sources are taken into account through parameters specified by the user. Other user specifications include option code numbers, indicating the user's preferences, and the physical dimensions describing the dwelling under study. The TYPE l9 subroutine uses the same methods to describe the heat transfer processes as the TYPE l7 and l8 subroutines employed. A significant aspect of the TYPE l9 room and basement subroutine is the two options available to the user regarding the simulated control over the heating or cooling system. The two control options are referred to as the energy rate control (mode l) and the temperature level control (mode 2). With mode l, energy rate control, the room temperature is deter- mined based on all of the heat losses or gains considered in the TYPE l7, l8, and l9 modules. The calculated room temperature is compared with user specified upper and lower room temperature limits. If the calculated room temperature is above the upper acceptable limit a cooling load occurs. If the calculated room temperature is below the specified lower room 7l temperature limit, a heating load occurs. When the calculated room temperature is between the upper and lower user specified limits a no load situation is assumed. When the latter situation exists no load is output for that time step. The heating or cooling load that is calculated for a particular time step, when the mode l option is being used, is assumed to be fully satisfied, instantaneously, by an unspecified source. In a real situa- tion the space load demand is not met instantaneously. Both the heating or cooling system has inherent start-up and shut-down characteristics affecting its output over time. However, fewer TRNSYS components are needed to simulate the thermal performance of a residence when the mode 1 option is selected and the resulting load determination is suitable for many purposes. The mode 2 option of the TYPE 19 subroutine is called the room temp- erature level control. In this option TYPE l9 determines the dwelling space load as in mode 1. In addition it considers the energy transferred into the room from sources such as a furnace or solar heat supply. In this way the user can simulate various space conditioning systems in order to study their effectiveness in satisfying the space load demand. The output of the modules simulating the energy supply becomes input to the TYPE l9 module and is considered along with other energy sources in attempting to satisfy the space load of the dwelling. The energy source may or may not have the capability to satisfy the space load demand. This will be reflected by the room temperature output form TYPE l9. The performance characteristics of the energy source and any related components are taken into account in the mode 2 option. As more factors 72 are accounted for the situation becomes more realistic and accurate. Energy source system components can include modules from the TRNSYS library representing solar system devices, heat exchangers, temperature controllers and others. 6.5 Summary of the TRNSYS Program The unique feature of the TRNSYS program is the modular simulation technique. This feature allows the user to create programs to simulate a variety of systems addressing building energy performance. There is no set input form for a TRNSYS program because the input depends on the sub- routines selected for use in the simulation. Each subroutine requires the same TYPE of information. The total input for a TRNSYS program is an accumulation of the inputs for each of the subroutines used to make up the program. To make use of the TRNSYS simulation system the user needs to per- form two tasks. First, the desired program has to be developed from TRNSYS modules. Second, the required input information has to be speci- fied. To complete the first task the user should have knowledge of the relationship between the physical components of the system to be simulated. To complete the second task the user should have knowledge of the factors affecting the performance of the system's components. For the components used in this study the user should have knowledge of the factors affect- ing the heat transfer in buildings. A knowledge of computer programming is not required by the user in order to use the TRNSYS simulation system. Both algebraic and differential equations are used in TRNSYS. Differential equations are used to describe the heat transfer situations 73 taking place under transient conditions. The only way the user is involved with differential equations is in specifying the initial values of the dependent variables when required. 7. THE NBSLD PROGRAM 7.l Purpose of NBSLD The National Bureau of Standards Load Determination (NBSLD) program was developed at the National Bureau of Standards by Kusuda (1976a). The purpose of NBSLD is to aid in the thermal design of buildings by pro- viding a means of accurately determining heating and cooling loads. The organization of NBSLD consists of an executive program and numerous sub- routines. Some of the subroutines may be used individually as main pro- grams when only the information provided by that subroutine is of par- ticular interest. The NBSLD program is flexible with provision for several modes in which it may be used. It can be used to determine the design heating and cooling load for a structure based on summer and winter design conditions or it can be used for a determination of the instantaneous heating and cooling loads based on hourly weather data for a particular location. Within both of these modes there are additional options available to the user. This flexibility permits the user to thoroughly evaluate each - aspect of a structure that may affect its thermal performance. In addi- tion to its thoroughness and accuracy the NBSLD program incorporates several unique features of thermal analysis not available in other heating and cooling load calculation programs. 74 75 The NBSLD program was applied to the residence described in section 4.0. The input and the various outputs are discussed in the following sections. Figure 7.l is the input for the NBSLD simulation of the example residence. The input data of Figure 7.l is included in Appendix C in a completed NBSLD input form. Figure 7.2 shows that two types of output are obtained from NBSLD when the design day option is selected. Each is produced by different NBSLD subroutines. Figures 7.3 and 7.4 are examples of the design day outputs obtained. Figure 7.5 illustrates a third output can be obtained when the hour-by-hour method of simulation is selected. This simulation method employs an hourly weather record to simulate actual climate conditions. Figure 7.6 is an example of an hour- by-hour simulation. 7.2 Input to NBSLD Most of the input information to the NBSLD program falls into one of three categories: (I) building operating data, (2) building physical data, and (3) climatic data. The building operating data category of input consists of informa- tion regarding potential sources of heat generation within the building and information regarding ventilation air characteristics. The operating schedules of lighting, equipment, and appliances which may add to the cooling load or alleviate the building heating load are input on an hour- by-hour basis. Acceptable limits of ventilation air temperature and ventilation air rates are also inputs in this category. 76 A description of the physical aspects of the building that influence its thermal performance are inputs in the category on building physical data. Room dimensions, constant heat transfer coefficients, building material properties, infiltration rates, type of heat transfer exposures, exposure areas, and exposure orientations are typical of the input data in this category. The building physical data category requires the greatest amount of input information to the NBSLD program. The climatic data category of input includes information on the geographic location of the particular building, summer and winter design conditions, and the time of year in which the simulation is being done. Some of the information in this category is used by the program to select the appropriate weather data from a weather data tape used when the pro- gram is run in the hour-by-hour simulation mode. Information in the first two categories may be used to describe the specific characteristics of a particular space within a structure such as a single office in a large office building. In a like manner this infor- mation may also be used to describe a single room within a residence when such a detailed thermal analysis of the structure is desired. For the discussion in this study the entire house is considered to be a single room since most residences strive to have nearly uniform thermal condi- tions throughout the inhabited space. However, should it be desired to investigate the effect of isolating certain rooms or functional areas from the heating system the NBSLD program has the capability to do so. Considering the entire house as a single room in no way alters the run- ning of the NBSLD program other than to reduce the amount of input infor- mation and to shorten the computation time. 77 Input to the NBSLD program is achieved by completing the input data form in Appendix C. The NBSLD input form contains 34 data fields, each requiring a varying amount of numerical or alphanumeric information. The total amount of input data required to complete the 34 input fields depends on the complexity of the various building constructions and/or the complexity of the building configuration. The input fields that are not self-explanatory are described in the following discussion. There are five inputs in field one. RUNID is an index for the cal- culation of conduction transfer functions with a l indicating a calcula- tion of transfer functions is desired. For the RUNTYP variable, the user must input either the value l or the value 2. A l indicates a desire to have an hour-by-hour determination of the heating and cooling load using hourly weather information. A value 2 indicates an interest in the design heating and cooling load for which hourly weather infor- mation is not required. The input for the ASHRAE variable is O. This signifies the use of the exact calculation procedure to convert the heat gains and losses to loads. The other option, the weighting factor method, is incomplete. The variable IDETAL controls the amount of NBSLD output. If a O is used, the output is the heating and cooling loads. If a l is used, the output will include the input data, the heating and cooling loads, and details of intermediate calculations. The input to the METHOD variable is O signifying the radiation exchange among the room surfaces is to be treated on a room-by-room basis (in this study the residence was assumed to be'a single room). No other option is currently avail- able. Input fields three through ll are daily schedules for lighting, appliance and equipment operation, and building occupancy for weekdays, 78 weekends, and holidays respectively. Values between 0 and l are input to these nine fields. These are normalized values with the maximums specified elsewhere in the input. Input fields 12 and l3 are 24-hour profiles of thermostat settings during cooling and heating situations. Input field l4 contains maximum and minimum limits for indoor temper- ature and humidity. Input field l5 specifies the simulation starting time and duration. Input field l6 is data pertaining to design condi- tions used when no weather tape is available. Input fields l9-2l describe the various building constructions. They are used as input into the NBSLD program as many times as there are different types of constructions in the building. The exterior walls of a typical woodframed residence, for example, may be described using two different constructions since the rate of heat transfer through the wall at the framing is likely to differ from the heat transfer rate through the wall between the framing members. The construction at the stud framing might consist of four layers of materials. In a typical construction they would be (from the inside out): gypsum board, wood stud, sheathing material and siding. Through the stud cavity construc- tion there are four layers of materials, typically: gypsum board, insul- ation, sheathing and siding. Using the construction at the stud framing as an example, input into field 19 would have the value 4, indicating the number of layers of materials. Information input into field 20 consists of five items: material thickness, thermal conductivity, density, specific heat and thermal resistance. This information is input as many times for each construction as there are different material layers in that construction 79 (i.e., four times in this example). Field 21 is a provision for an alphanumeric description of each of the corresponding material layers input into field 20. Information is input into field 2l as many times for each construction as there are different material layers. This alphanumeric information does not enter into the calculations with the program, but appears in the output for clarity purposes. The total amount of input into fields l9-2l required to describe the wall construction at the stud framing is nine punch cards or lines depending on mode of input. This is an accumulation of one entry in field l9, the number of layers of materials in the construction, and four entries for each of the fields 20 and 2l. It is the input information of fields 20 and 2l that is required for a determination of the conduction transfer functions (discussed in section 7.4.4), one of the features of the NBSLD program. Specifying input information of this detail may require more effort than is required for obtaining the input for most other heating and cooling load determination programs. However, unless the user is doing research involving many unusual materials or building constructions, the conven- tional materials of construction are not so numerous nor the typical building constructions so varied that the specifying of input for fields l9-Zl becomes a difficult, time consuming task. The NBSLD program has the capability to store the conduction transfer functions once they have been computed for a particular construction and recalled whenever that same construction is again encountered. The storage mode is selected through input of the RUNID variable in input field one. By having to 80 calculate the conduction transfer functions only once for each construc- tion the amount of input and computer computation time is reduced. The information input into fields 29-3l pertains to a description of the configuration of a building. In field 29 there are eight items of input. They are an identification of the type of exposure (i.e., wall, roof, etc.), a code relating this exposure to one of the construc- tions described in fields l9-2l, the area of the exposure, and the orientation angle of the exposure in degrees clockwise from the south. The four remaining inputs to field 29 include the overall heat transfer coefficient of the exposure, a shading coefficient, and a shadow param- eter indicating whether or not external shading of the exposure occurs. Fields 30 and 3l provide for input having to do with external shading devices such as overhangs and window fins. All the input in fields 30 and 31 are in the form of dimensions locating the shading device with respect to the shaded window or wall. Fields 29-3l are input as a unit into the NBSLD program as many times as there are different exposures. There may be only one input each for the roof-ceiling and for the floor constructions. Simply shaded structures may be described with a small amount of input. The NBSLD program has the capability to accomodate very complex configura- tions when necessary. Only in fields l9-2l and fields 29-3l is the amount of input infor- mation variable from one computer run to the next. The input into the remainder of the 34 input fields is independent of the various construc- tions and differing configurations of the building. Once the input form is completed the information may be input into a computer by way of the 81 punched card mode or interactively depending on the desire of the user and the available computer input facilities. The NBSLD program was applied to the example house described in section 4.0. Figure 7.l is the input data to NBSLD for the example home. This same input is included in the NBSLD input form in Appendix C. 7.3 Output from NBSLD Due to the nature of the input information and the structure of the NBSLD program there are two design load outputs produced when the design day mode (RUNTYP = 2) is used. To illustrate how the NBSLD program functions in the RUNTYP = 2 mode a schematic representation of the rela- tionship between the type of input, the program structure, and the out- put is shown in Figure 7.2. The two outputs (Figure 7.3 and Figure 7.4) are design day loads calculated on the basis of the input of design day conditions. Each of the outputs is produced by a separate segment of the NBSLD program using a different heat transfer calculation methodology. The design load output in Figure 7.3 was produced mainly by the NBSLD subroutine, winter. This subroutine employs steady state heat transfer methodology. The three items appearing in this output are the sensible heating load (ll,Ol7 BTU/HR), the latent heating load (0), and the total design heating load for the residence (ll,Ol7 BTU/HR). Sub- routine winter is used only when the NBSLD program is run in the RUNTYP = 2 mode. As illustrated in Figure 7.2 there is a second design day output from the NBSLD program. The subroutines that produce this output have lol-OOICQ ..U "GUS! 82 4:;UCUOUIaoaoaouoO-eruccue.0.;Uououocouououuaa :.O.o.o-a.:.;.:.:.a.o.:.:.9.c.:.€-C.:no-c.:.o.o alo.°.°la‘°OOOCO°O;IJI°OCC:I°C°.aOOIODOIcOOIOI $HCITNINSIDCCKIN‘ IIOING/flOO'lN‘ O .0393700080.°oooao° aouc§ououo§uvoCoUoUI~0vovo~0vuu0~oDoUo~IOoucg.U JO°I°.°.a.cI‘O;I:ODO:O°I;O:|°.;.GO°I:OCO°O;O°O JoénéoéocoJOCaCoOoOoJoO-éDJIC0‘IOOOVO-OIC000000 wag-30303.:Iuouotiaog.505outiiUcOuUcaoUoOnU.Uu 3nCoO-O-JoOoOo$-OOO-J.00300000300030000-OQOoOoO 300.000.00005000000000000-900vDoCoOoOoOoOoOoOo 7.007.007.009.. ......-o...‘..oo..oc..oc..00‘.........-0......00..00..00..IO..OO.‘OO..OO...O... o’Il oo!!!o 00.105 09393700070370.0300 003.379.0703,0IOJO= 5'930- .0536 O O IN A? 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CONDITIONS: CONDITIONS I l WINTER OR : : SUMMER DESIGN HEAT HOURLY LOAD BASED DESIGN LOAD: ON WINTER HEATING OR CONDITIONS COOLING Figure 7.2 Type of output produced when the NBSLD program is run in the Design Day mode (RUNTYP = 2). 84 HEATING LOAD IN BTU PER HOUR SENSIBLE LOAD = 10955. LATENT LOAD = 0. TOTAL LOAD = 10955. Figure 7.3 Design day heating load output from the NBSLD program. 85 the capability Of determining the heat flow through the constructions of a building under unsteady state conditions in either a heating or cooling situation. Thus, the resulting output is the design heating load for the structure if winter design conditions are input into the program; or the design cooling load for the building if summer design conditions are input. A design day heating load output is shown in Figure 7.4. The format Of the output is the same whether the output is a heating or cool- ing load.. In the cooling load output a negative sign preceeds the load values indicating cooling. The output is displayed in hourly printouts for a 24-hour period with each hourly printout consisting Of seven items of information. In order Of appearance in the printout they are: (l) the hour of the day, (2) the outdoor drybulb temperature, (3) the outdoor wetbulb temperature, (4) the indoor drybulb temperature, (5) the indoor relative humidity, (6) the sensible heat load (QLS), and (7) the latent heat load (QLL). In addition to the 24 hourly printouts there is output information on the total load (269,098 BTU), the maximum hourly load (ll,810 BTU), and the time that the maximum hourly load occurred (8th hour). To this point the discussion concerning ouptut from the NBSLD program has considered only the case when the design day mode (RUNTYP = 2) is utilized. Figure 7.5 illuStrates that a third heating or cooling load output may be Obtained from the NBSLD program. 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(5 33 O 20 23 4! 4! .l T62 LONG LAT TZN ZLF RHOW a 4'67 43.33 .zb T7 NAMERM (Col. 3-36, Alphanumeric) N TICNO CEL T8 IROT INCLUD (INTEGER) O I T9 NLAYR (INTEGER) (NOT INPUT) IRF 20 Tst LAYER-innermost 0 20A 2nd LAYER 203 3rd LAYER 20c 4th LAYER ééA Nth LAYER 2) LAYER DESCRIPTION (24 CoT.max. Alphanumeric) 67)!“ sum 8 O A RD Tst LAYER-INNERMOST ZTAFIBre INsuLATION 2ndLAYER ZTBSHEATHING/Dec ING 3rdLAYER 21C$toa G/RJOOFIN 4thLAYER ZTN Nth LAYER 22 23 T63 24 25 .___,. NLAYR (NLAYR = ZERO CARD INDICATING END OF NALL/ROOF/FLOOR DATA) L___. 0 ZROOM ()2) ROOMNO QLITY QEQPX QCU FLCO FRAS TS CFMS ARCHGS ARCHGN I o o o o o o o o o ARCHGM ZNORM A32. / 1w IL ISTART ILEAVE 3 o 9 )7 TUL TIL QCMAX QHMAX DBVMAX DBVMIN ’79 6% 99,000 99,000 6% so 26 ITHST ITK (INTEGER) C) CD 27 NNEXP (4) NS NW NN NE (INTEGER) 2. :2 2: :2 28 L N H so 30 8 T64 29 ITYPE IRF A Azw U SHADE ABSP SHD I 5’ I500 o o o .78 0 30 SHADw (30,15) FL HT FP Aw BHL BHR D <> <3 c> <3 c> c> ca 31 FF) AT B) C] FP2 A2 82 c2 0 c> 0 <3 <3 «0 0 <3 29A ITYPE IRF A Azw U SHADE ABSP SHD 2 / 360 o o o .7 8 o 30A SHADw (30,15) FL HT FP Aw BHL BwR D 0 <3 c> o o C) c: 31A FPT A) B) CT FP2 A2 82 c2 0 o O o o o O o 32 UENDw UCELNG AENDN ATCHT ARCHGATTAIRNT C> c> c: c3 c: I 33 IEXTED IEXMS IEXME { NTVNT NVENT (INTEGER) C) C) C) CD CD 34(BLANK DATA CARD INDICATING END OF DATA) (INTEGER: ITYPE AND IRF) (INTEGER: ITYPE AND IRF)