PSYCHROMETRIC ASPECTS OF HEAT AND “OISTURE REMOVAL FROM A POULTRY HOUSE BY VENTILATION Thesis for the Daft“ of M. S. MICHIGAN STATE UNWERSITY Mohammad Saeed 139966 ___._. _ AA.- ? "7 3 141151115 p. , Michigan Stats University Illa. 4' 4 .. PSYCHROMETRIC ASPECTS OF HEAT AND MOISTURE REMOVAL FROM A POULTRY HOUSE BY VENTILATION By Mohammad Saeed A THESIS Submitted tO Michigan State University in partial fulfillment Of the requirements for the degree Of MASTER OF SCIENCE Department Of Agricultural Engineering 1966 ABSTRACT PSYCHROMETRIC ASPECTS OF HEAT AND MOISTURE REMOVAL FROM A POULTRY HOUSE BY VENTILATION By Mohammad Saeed The primary objective Of this investigation was to study the interactions of temperatures, humidities and air flow rates in a poultry house during various summer cli- matic conditions. The work was carried out as follows: 1. A continuous record Of the inside dry and wet bulb temperatures, outside dry and wet bulb temperatures and attic temperatures was made with a recording potentiometer. Air velocities at various key points in the rectangular slotted inlet were measured and the air flow rate was determined. The flow was varied by Operating different number of fans and varying the width of the openings. The total air flow volume was checked by calculat— ing the air exhausted by the fans Data were analyzed: From the continuously re— corded data, temperatures at 5 minute intervals were taken. At these temperatures outside and Mohammad Saeed inside enthalpies, humidity ratios, specific volumes and relative humidities were determined. The heat and moisture produced by the birds at various ambient temperatures were estimated from published data. Heat and moisture inputs and outputs were than calculated. 5. Figures were drawn to show: (a) The variation of inside temperature with different flow rates. (b) The variation of outside temperature with time on different days. (c) Variation of heat and moisture input and output with different flow rates. (d) The change in inside and outside humidity ratios at various flow rates. (e) The inside conditions on a psychrometric chart. From the study of these diagrams, the following con- clusions were drawn: 1. The dry and wet bulb temperature differentials between inside and outside appear to be quite constant during a given day for a specific house. Evaporative cooling in a house depends upon the dry and wet bulb temperatures of the incoming ventilation air and the evaporative conditions and air distribution within the house. 3. Mohammad Saeed A decrease in ventilation air flow does not necessarily decrease the moisture removal ability of the air and under some cases will bring about more evaporative cooling resulting in a cooler house interior. The exhaust ventilation air relative humidity for different days having various climatic conditions was quite constant for the house studdied. The "humidity range" for this house was 62-72 per cent. This humidity range would appear to be a measure of the ventilation system effectiveness in moisture removal and evaporative cooling. Approved 277% j: W \.Major Professor Approved Wm M par men airman ACKNOWLEDGMENTS The author wishes to express his sincere thanks to Dr. Merle L. Esmay of the Agricultural Engineering Depart- ment, under whose inspirational guidance, constant super- vision, and unfailing interest this investigation was undertaken. He also wishes to thank Mr. and Mrs. Burns of Millington, Michigan, for allowing their poultry house to be used for this study. Appreciation is extended to Mr. HaJime Ota, Agri— cultural Engineer, U. S. D. A., for sending the necessary literature regarding the study and his Offer for further help. He is thankful to Mr. James Cawood for his help with instrumentation. He also wishes to thank Professor John M. Moore, of the Poultry Science Department for his assistance and valuable consultation. Finally, recognition and appreciation is expressed to those who contributed in one way or another to this investi— gation. ii TABLE OF CONTENTS ACKNOWLEDGMENTS LIST OF FIGURES INTRODUCTION OBJECTIVE REVIEW OF LITERATURE Heat Moisture. . . . . . . . . Ventilation. . . . . . . . MEASUREMENTS The Poultry House. Temperature Measurements Velocity Measurements Fan Output Measurements. Static Pressure Difference Measurements Other Observations CALCULATIONS Air Flow. . Air Exhausted Temperature CorrectiOns. Relative Humidity, Enthalpy, Humidity Ratio, and Specific Volume . Air Flow in Lbs. Per Hour Heat Transfer Through Walls . Heat Transfer Through the Ceiling Heat From Electric Lamps . . Heat Removed By the Ventilation Bird Heat Production. . Moisture Produced. Heat Input and Output iii Page ii DISCUSSIONS AND FINDINGS . Temperature Differentials Heat Balance . . Moisture Balance . . . Evaporative Cooling on August 10, 1965. Air Flow. . . . . . . Winter Operation . CONCLUSIONS . . . . BIBLIOGRAPHY . . . . . . . APPENDIX A. . APPENDIX B. . iv Figure O\U'1 10. 11. 12. 13. 1A. 15. 16. 17. 18. LIST OF FIGURES Page House Details . . . . . . . . . . l3 Arrangement of Cages in the House . . . lA Arrangement of Cages (Another View). . . 1A General Appearance Of Birds In Cages . . 15 Droppings From the Hens. . . . . . . 15 Droppings From the Hens. . . . . . . l6 Droppings From the Hens. . . . . . . l6 Ventilation Air Inlet Set At A Inches . . 17 Exterior View Of the Southern Wall . . . l7 Arrangement of the Exhaust Fans (Exterior View). . . . . . . . . . . . . 19 Type "A" Fan in Operation . . . . . . 19 Type "B" Fan in Operation . . . . . . 2O Ventilation Air Inlet on the Outside Northern Wall . . . . . . . . . 20 The Potentiometer and the Ice Bath . . . 21 Technique of Holding the Probe in Air Current . . . . . . . 2l Hot Wire Anemometer . . . . . . . . 23 Points of Velocity Measurements . . . . 23 23 Vane Anemometer Figure 19. 20. 21. 22. 23. 2A. 25. 26. 27. 28. 29. 30. 31. 32. 33. 3A. 35. Velocity Measurement Through l/2-inch Inlet Fan Details . . . . . Manometer. Inside and Outside Temperatures.At 5 Minute Interval on July 29, 1965 Inside and Outside Temperatures At 5 Minute Interval on July 29, 1965 . . . . Inside and Outside Temperatures At 5 Minute Interval on August 10, 1965. . . Inside and Outside Temperatures At 5 Minute Interval on September 7, 1965 Inside and Outside Temperatures At 5 Minute Interval on November 11, 1965 . . Inside and Outside Temperatures At 5 Minute Interval on November 11, 1965 . . Heat and Moisture Inputs and Outputs At 5 Minute Interval on July 29, 1965 . Heat Inputs and Outputs on August 10, 1965. Heat Inputs and Outputs on August 10, 1965. Heat and Moisture Inputs and Outputs At 5 Minute Interval on September 7, 1965. Heat and Moisture Inputs and Outputs At 5 Minute Interval on November 11, 1965. Heat and November Moisture Interval Moisture Interval Moisture Inputs and Outputs On 11, 1965 . . . . . . . Inputs and Outputs At 5 Minute on August 10, 1965. . Input and Output At 5 Minute on August 10, 1965. vi Page 2A 25 27 A0 41 A2 43 AA 45 A7 A8 49 50 51 52 55 56 i __.._ _ 445': g, * __ — Figure Page 36. Inside and Outside Humidity Ratio Differ— ence at Various Flow Rates . . . . . . 6O 37. Inside Conditions 0- Psychrometric Chart . 62 38. Velocities at Various Points on Outside of Fan on November 11, 1965. . . . . . 102 vii INTRODUCTION Proper ventilation of a poultry house is necessary to replace the stale, moist, and contaminated inside air with fresh and clean outside air. Since an exchange of air generally involves a loss or gain Of heat, the venti- lation rate must be kept in proper balance with all environ- mental factors tO maintain the desired temperature. Opti- mum environment is not based on temperature alone but upon the interactions of temperature, humidity, radiation and air movement. Optimum environment keeps the poultry at peak health and maximum productivity by minimizing the stresses. Environment involves two sets Of controls, namely: the homeothermy of the chickens, and the man—made control for regulation Of the environment around the chicken. The design, development, and operation of a ventilation system is based on conduction, convection, radiation, air movement, and air water-vapour relationships. Properly de- signed houses and environmental controls are necessary. Without these it is not always possible to cope with sudden and severe temperature and humidity changes. Environmental changes within the house are undesirable because birds can— not adjust to sudden changes. Variation in temperature, humidity, and air movement may be allowed that do not affect the growth, production, health, and general well-being of the housed birds. At Summer temperatures in the range Of the upper housing limit (85 to 90 degrees F), the amount of ventilation air movement to dissipate the metabolic heat of the birds as well as the moisture is critical. Some evaporative cooling benefit can be derived if the outside wet bulb temperature is not too high. Proper design of the poultry house insulation and ventilation systems need careful engineering analysis. Many studies have been carried out on various engineering aspects of the poultry houses. Calorimetric studies have been made on laying hens to determine the behavior of hens under vari- ous conditions. Because of easier environmental control and handling efficiencies, better systems can now be designed and constructed. This study was conducted on one poultry house to ana- lyze the effect of prevailing summer climatic conditions and the volume of ventilation air exchange on: 1. Evaporative cooling 2. Heat removal, and 3. Ambient conditions in the house. OBJECTIVE The objective of this research study was to determine and analyze some of the interactions of evaporative cooling, water evaporation, and air flow rates in a poultry house during various summer climatic conditions. REVIEW OF LITERATURE A prOperly controlled environment is necessary to keep laying hens at peak health and productivity, and re— sult in lower medication costs, better feed conversion, cleaner birds and eggs, longer building life, and better working conditions (6) (21) (22). Environmental control involves the factors: heat, moisture, and ventilation. The review of literature was, therefore, made in the following three parts: (1) Heat, (2) Moisture, (3) Venti- lation. Heat Optimum temperature ranges vary considerably with the age and type of birds. Rapid temperature fluctuations should be prevented, for birds cannot adjust quickly to swift changes (22). Esmay (10) states that the theoretical low temperature for housing adult birds is 61.7 degrees F. which is the lower limit of their thermal neutrality. In cold climates a practical housing temperature of 55 degrees F. is, how- ever, very satisfactory with a minimum of A5 degrees F. The upper housing temperature should desirably be not above 90 degrees F. According to Barott and Pringle (3) optimum tempera- ture for poultry chicks over 5 weeks old may be considered to be 70 degrees F. Ota and McNally (20) state that as ambient tempera- tures were reduced below 85 degrees F., the day sensible heat tended to stabilize until about 45 degrees F., at which time it began to increase again with the decreasing temperatures. The hens were apparently able to maintain a constant rate of heat dissipation between 85 degrees F. and A5 degrees F. Perhaps this could be considered a "comfort— able" range of temperatures. Both day and night latent heat generally decreased with decreasing temperatures. They also showed that both sensible and latent heat decreased with age. Dukes (8), Mitchell (17), and Kibler (14) showed that metabolism of laying hens decreased with age. The tests by Ota, Garver, and Ashby (19) showed that total heat production decreased from SM B.T.U. per hour per hen at A0 degrees F. to 3A B.T.U. per hour per hen at 85 degrees F. This 37 per cent reduction in total heat emitted was in contrast with the heat production estimated by Mitchell and Kelley (17). The latent heat production per bird as found by them (Ota, Garver, and Ashby) was three to six times as large as the estimates of 5 to 8 B.T.U. per hour per hen at temperatures between A0 to 60 degrees F. by Mitchell and Kelley. Moreover, at an average temperature 0f 85 degrees F. the tests by Ota, Ashby (19) showed sensi- ble heat as 1“ per cent and latent heat 86 per cent of the total, while Mitchell and Kelley estimated that latent and sensible heat were equal. At the lower temperature more feed was consumed and more water was needed to utilize the nutrients. At the high temperature less feed was eaten and less water was used for metabolism, but more water was needed to permit evaporative cooling (l9). Ota and McNally (20) also reported that generally the leghorns dissipate more sensible heat per unit weight than other breeds. Thus it would appear that white leghorns were the least protected against low temperatures and proba— bly the most affected by it as Hutt (13) has also indicated. Moisture The maximum humidity that can be tolerated by birds without loss of production varies with the temperature and duration. Maintaining correct humidity conditions minimizes problems of wet litter, dirty eggs and birds, building de- terioration, moisture condensation and working comfort (20, 23). Esmay (11) states that adult chickens will tolerate a wide range of relative humidity. In cold climates rela— tive humidity may be maintained satisfactorily up to 80 per cent with a 55 degree F. housing temperature. Lower relative humidities are desirable with high housing tempera— ture. Chickens can better tolerate temperatures above 85 degrees F. if the relative humidity is below 55 per cent. When the outside temperature falls, air exchange is sacri- ficed to conserve heat. In such a case, fecal water and respiration moisture from the chickens cumulate in the house. Moisture in the house could be reduced by removing litter and droppings. The partition of the two sources Of moisture is academic in the design of a ventilation system as moisture is evaporated from the droppings and litter. At other times, however, respired moisture from the chickens may be condensed on surfaces within the house. Fecal production is related to feed consumption and varies from 75 to 80 per cent Of feed as the ambient temperature increases from 20 to 100 degrees F. (10). Ota and McNally (20) showed that 5” per cent Of the total water output Of white leghorns at 9“ degrees F. was evaporative. This percentage decreased to about 30 per cent at 26 degrees F. About one—third of the total water output from white leghorn hens (more than 220 days of age) was evaporative at 65 degrees F. Ota (20) states also that the evaporative water per— centage at various temperatures may be different depending upon age and perhaps egg production. With tests on Rhode Island Reds at 92 degrees F. there was 6 pounds per day per 100 hens difference in evaporative moisture between hens producing 65 and 23 per cent eggs. Younger hens produced 21 per cent more eggs than older hens in a test. The fecal production rate varied with feed and water consumption as well as egg production. Barre and Sammet (A) state that it is not possible to specify an optimum relative humidity. The optimum range would shift, depending on the temperature, since these two factors are interdependent in their effect on physiological reactions. High relative humidity at high air temperature increases the difficulty of dissipating heat by evaporation and this is an adverse factor with respect to body tempera- ture regulation. At environmental temperatures of 50 degrees F. or less, about 10 per cent Of the total heat appears as latent heat in respired and is not available for tempera~ ture control in ventilation (A). Additional heat is required to remove a portion of excreted moisture by ventilation. Ventilation A.S.A.E. Yearbook (7) defines ventilation as a system of air exchange which accomplishes one or more of the follow— ing: 1. Provides desired amount of fresh air to all parts of the shelter without drafts. 2. Maintains temperatures in the shelter within de- sired limits. 3. Maintains relative humidity within desired limits. Barre and Sammet (7) state that the amount of venti— lation required depends on the indoor and outdoor tempera— tures, the U value of exposed surfaces and the rate at which moisture is being produced. The temperature difference between supply and house air is highly important, because temperature control in the house is strongly affected by the difference. The greater the difference in the inside and the outside temperatures, the more is the conducted heat gain or loss.(2) Proper distribution of the ventilation air creates suitable combinations Of temperature, humidity, and air motion in the occupied zone of the house. TO obtain com- fort conditions within this zone, standard limits have been established as acceptable "Effective Temperatures." This term comprises air temperature, motion, humidity and their physiological effect on the body. Any variation from ac- cepted standards of one Of these elements may result in dis- comfort to the occupants. The same effect may be caused by lack of uniformity of conditions. Such discomfort may arise due to excessive room air temperature variations (horizon- tally, vertically, Or both), excessive air motion (draft), failure to deliver or distribute the air according to the load requirements at the different locations, or too rapid fluctuations of room temperature or aim motion (gusts) (2). A.S.A.E. Yearbook (7) states that ventilation is ac— complished in an exhaust system by the creation of a low pressure in the structure, causing fresh air to enter where— ever openings exist. Pressure differences across walls in ventilated shelters should range between 0.02 and 0.0A inches, water gage, with satisfactory inlet area (7). 10 PrOper air distribution can be Obtained by varying the in- take cross-sectional area to fit the situation. The use of two or more fans Operating together on a given space leads to better distribution of the air cur- rents than is possible with a single fan, if they are cor- rectly situated with respect to the air inlets and to each other (28). Modern studies have, however, shown that prOper distribution of ventilation air could be had if the inlet is properly located irrespective Of the number and location of the fans (10). A distinctive feature Of a propeller fan at work is that air approaches the fan from all directions on the in- take side, quite a considerable proportion entering radially, while on the delivery side the air is discharged very nearly in a solid cylinder, although the velocity is not uniformly distributed (28). These fans work best when there is no tube or other restriction on either side, but if ducts or tubes are neces- sary, they should be as short as possible, and their diameter should be at least 20 per cent greater than that of the fan. According to Allen, Walker, and James (15) the velocity Of air and consequently the air quantity depend upon the static pressure. Esmay, Zindel and Sheppard (11) state that the actual fan air delivery is dependent upon the shape of the blade, number of blades, shape of the fan orifice, and Speed of operation. 11 The capacity and speed of a fan vary as the square root of the static pressure difference (1, 5, 29). MEASUREMENTS The Poultry House This study was conducted on a AO' x 180' x 8' pountry house located near Millington, Michigan. The house was equipped with A032 cages each measuring 8 in. x 16 in. The arrangement of the cages is shown in Figure l and illustrated by Figures 2 and 3. On the various days of experimentation, namely July 29, 1965, August 10, 1965, September 7, 1965, and November 11, 1965, the house con- tained 6587, 6556, 6613, and 6095 birds respectively. The hens were H & N leghorns hatched on April 10, 196A. Figure A gives the general appearance Of the birds in the cages. The droppings from the hens are seen in Figures 5, 6, and 7. They formed well—defined cones. Figure 1 shows dimensions, orientation and other de— tails of the poultry house. The adjustable slots on the southern side of the house were completely closed during the experiment, while those on the Opposite side (A7 in number each A5 inches long) were set at desired widths. Figure 8 shows the inlet set at A—inches. There were 6 exhaust fans: 3 of type "A" with a rated capacity of 10800 c.f.m. and 3 type "B" with a rated 12 13 :Ltsoh— sd'——I-s'<')-I-—35 433.15 450% 323-45011 4w 4OFT_ ,. 40' , I ELEVATION l T“ ‘ <3 d‘ E. E Q 3 r :3 . II): .J o _J 9 . u (I) '- mf' u ‘3' " '3 g 5 _5/8 Pvaooo 2 finsanuoms ., o .3 J 5 i (0 F J...w._l_ 2' g :23 III WALLS DETAILS .- - 3 < II. .- = I" F o o '0 ‘0 Q _’ Q' :3 ' J" z 3 I 3 4 if ROCKWOCL-w 5‘ 5's“Pvaooo ‘ :3 iv CEILING DETAILS F FAN P POTENTIONETER M MANOMETER R ICE BATH THERNOCOUPLES POSITIONS I INSIDE. DB 2 INSIDE W8 3 OUTSIDE DB 4 OUTSIDE W8 .iL 6 ATTIC W new nous: DETAILS ’1 1+ “arc"iflf'w . late, as. . ‘2 ‘ b‘a’flw Figure 3.--Arrangement of cages (another View) I}; , and...’ Figure A.--General appearance of birds in the cages. C '1. “ i . Figure 5. —-Droppings frOm the hens. t. Q. . 7 . . . ‘0»: '2 ‘ . - mks“ \xk \\§\\\\N{\ \ I Figure 7.--Droppings frOm the hens. I v.0, ' .- > d Figure 9.--Exterior view Of the southern wall. 18 capacity of 10000 c.f.m. at 1/8—inch static pressure. The exterior view of the southern wall is shown in Figures 9 and 10, which give the position and arrangement of the fans also. Figures 11 and 12 show the two types of fans in Oper- ation. The difference in the design Of the blades should be noted. The outside air is Obtained through a series of open- ings near the ceiling on the northern wall (Figure 13). The air then passes through the adjustable slots to enter the house. The ventilation rate was varied by putting a differ- ent number of fans into Operation and varying the inlet width. Wall and insulation details are shown in Figure 1 (iii) and (iv). Figure 13 also shows the metal roof and siding. Temperature Measurements Inside dry and wet bulb, outside dry and wet bulb, attic and reference junction temperature measurements were made with thermocouples. These thermocouples were of the copper constantin type. To get wet bulb temperature measure- ments with thermocouples, their junctions were enclosed in bulbs made from wick and then properly wetted. The potenti- ometer was,of the Brown recording type and is shown in Figure 1A. A Dewar flask was used as an ice bath for refer- ence to avoid melting of the ice. Checks on the temperatures were made with a half degree certified thermometer and sling psychrometer. 19 '_ V ‘ I. , , ‘_ ‘ ‘ ‘ ‘.‘v _‘- ._ '. r " V .t" ‘.“ ~' I ’8’." P'.‘ «.3. ,l' l o ' I ‘ l \ f v I . Figure 10.—-Arrangement of the exhaust fads. A ,/,.//,/,w,‘-----------_-_-_ Figure 11.~— A n L \/ Figure 12.--Type "B” fan in operation. .I‘ Figure l3.--Ventilation air inlet on the outside northern wall. F'- "4/ Figure lA.--The potentiometer and the ice bath. Figure 15.--Technique of holding the probe in air current. .4 22 Velocity Measurements Measurements of the ventilation air velocities were made with a hot wire anemometer (Figure 16). The probe was held in the air stream at the point Of measurement taking care not to interrupt the air flow and thus produce un— desirable currents which would affect the readings. The technique of holding the instrument and keeping the probe in the air current through the slot is shown in Figures 15 and 19. The readings were noted when the indicator was stationary for a while to ensure that the measurements did not correSpond to the periodic gusts. The velocities as read by the instrument were in feet per minute. The readings were taken at various key points (Figure 17) in the slot to get a true velocity profile through the slot. Fan Output Measurement The air exhausted by the fans was also measured to provide a check on the ventilation air. The face of the ex— haust grille was marked Off into a number of equal rectangles and velocities were observed at mid points Of these spaces (Figure 20). A vane anemometer (Figure 18) was used for these velocity measurements. For consistency the vane anemometer was previously checked with the hot wire anemo- meter. This was done by putting them in a uniform air stream created by a fan in a closed room. One set of ob— servations was: 23 PROBE LV C M FIG IB‘. VANE ANEMOMETER “\———- IIO VOLTS LC- FIG SIHOT WIRE ANE’MOIIETER 0' in IT T --—- -——ee —— —-—45. ' —-—---- ———03- —---"I 03 06 09 r . ‘ I u__9_..| | I.._"$—~ L1 ‘45 r‘ "‘ a. I L ‘ .1 ‘_ —-—-—%‘ 1‘2. ‘ _.3_ «Z I I FIG I72 POINTS OF VELOCITY MEASUREMENT g .yr‘ I Aug. , ,. Figure l9.—-Velocity measurement through l/2-inch inlet. I 25 IHGZO FAN DETAM§ [/1 // p/V xi // A”? 35!! 9/ CL EAR : I A ‘ . V4 HmK *- ! rj/ 4IN.0£L L5 / .37 UL. « .31- :65” IA '6 5 'I r* II |.5" 26 Hot wire anemometer readings every 15 seconds were: 850 850 850 850 850 850 800 800 850 850 850 800 850 850 850 850 850 850 850 850 800 Average = 8A0 F.P.M. Simulataneous reading shown by the vane anemometer in the 5—minute interval was A230 feet, i.e. a velocity of 8A6 feet per minute. The difference was less than one per cent. Static Pressure Difference Measurement The manometer (Figure 21) was levelled and the bubble centered in the circle. The micrometer dial was set with zero in front and the movable indicator at zero. The well was filled and adjustment made by carefully moving the dial left or right until the miniscus in the guage glass read ex— actly zero. The liquid was sucked up into the expansion bulb and then released. The miniscus was again found at zero. This ensured the absence Of any air bubble. The pro— cess was repeated if the miniscus did not return to zero. The well was raised or lowered so that two complete revolutions of the dial indicated 0.01 inch on the scale. Then one tube was placed inside and the other outside to obtain the static pressure difference. Other Observations Record of the outside wind direction and the number of eggs was also kept. 27 35.202; 3 e: Buzuu 92.44261. any—.4052. wqm<>oz .25 «upmzomoi Sam zoazaaxu moss J . udmmao m A a: .12 m..— 72 6.! CALCULATIONS Air Flow Q = V . A where Q = Air flow V = Velocity A = Cross-sectional area. Considering the slot as shown in Figure 17, the velocities (or average velocities) at points 1, 2, and 3 are known. These points may be regarded as the key points of the left quarter, middle half, and right quarter panel respectively. Therefore, Air flow through any panel = Velocity at l X quarter panel area + velocity at 2 x half panel area + velocity at 3 x quarter panel area. Total flow = Sum Of the flows through all panels. In cases where the velocity measurements were taken every third panel, it was assumed that a panel takes care Of those flanking it on either side. The summarized calculations follow: July 29, 1965: Length of Opening = A5 inches Width of opening = A inches 28 29 Area of the Opening = l l/A sq. ft. Quarter area = 5/16 sq. ft. Half area = 5/8 sq. ft. Air flow = 2(500x5/l6+A00x5/8 +3(A16x5/16+3OOX5/8 +3(A33X5/l6+333x5/8 +3(500x5/16+367X5/8 +3(633X5/l6+A50x5/8 +3(650x5/l6+Al7x5/8 +3(700x5/16+A83X5/8 +3(533x5/16+A00x5/8 = 2AA6O C.F.M. +300x5/16)+3(367x5/16+350x5/8+300x5/l6) +267x5/16)+3(A67x5/16+367x5/8+300x5/16) +267x5/16)+3(A17x5/l6+300x5/8+250x5/l6) +3l7x5/16)+3(750x5/16+A50x5/8+333x5/l6) +A00x5/l6)+3(583x5/l6+A50x5/8+Al7x5/16) +333x5/16)+3(617x5/l6+A17x5/8+A17x5/16) +367x5/16)+3(600x5/l6+550x5/8+A67x5/l6) +300x5/l6)+3(A33XS/l6+333x5/8+233X5/l6) Air Exhausted Three type "A" fans: Length of rectangles across the grille = 8.25-inches Width of rectangles = 3.75-inches Width Of the lowermost rectangles = 3-inches Therefore, air exhausted by each fan = 3 x 8.25 x 1/1AA x (570 + 560 + 590 + 610) +3.75 x 8.25 x 1/1uu x (1200 + 820 + 950 + 1120 +1080 + 1070 + 1050 + 1200 + 1110 +980 + 1090 + 1120 + 1050 + 980 + 960 + 810 + 820 + 760 + 980 + 730 + 800 + 870 + 770 + 780 + 660 + 650 + 610 + 600 + 610 + 590 + 610 + 680) = A290 C.F.M. Two type "B" fans: Length of rectangles across the grille = 7—inches 30 Width of rectangles = A-inches Width of lowermost rectangle = 2.25-inches Air exhausted by each fan a 2.25 x 7 x l/lAA x (560 +570 + A90 + 560 + 630) + A x 7 x l/lAA x (680 + 530 + A10 + 350 + 380 + 730 + 850 + 630 + 710 + 680 + 720 + 780 + 750 + 830 + 860 + 730 + 660 + 710 + 750 + 770 + 690 + 610 + 530 + 7A0 + 780 + 710 + 660 + 690 + 710 + 800 + 770 + 850 + 920 + 870 + 900 + 850 + 860 + 870 + 760 + 860) = 593A C.F.M. Therefore, air exhausted by the fans (3 type "A" and 2 type "B" = 3 x A290 + 2 x 5934 = 2u7u1 C.F.M. Against 2A660 C.F.M. Similarly the ventilation air flow on other days were determined. The results were: August 10, 1965: 1. Width of Opening = A—inches Number of fans = 5 Total Flow = 2A7A0 C.F.M. 2. Width of Opening = 2-inches Number of fans = 5 Total Flow = 19740 C.F.M- 3. Width of Opening = 2-inches Number of fans = 3 Total Flow = 17600 C.F.M. 31 September 7, 1965 1. Width Of opening = A-inches Number of fans = 5 Total flow 3 28070 C.F.M. Width of Opening a 2-inches Number Of fans = 5 Total Flow = 21A20 C.F.M. November 11, 1965 1. On November 11, 1965 from 2:30 P.M. to 3:15 P.M. one Of the type "A" fans with a short circular duct on outside was in Operation. a method of dividing the area into a number of concentric zones and measuring the velocities on the circle enclosing the area of each zone was used. shows this kind of arrangement. Width of opening = 1/2—inch Number of fans a 2 Total flow = 8150 C.F.M. Width Of Opening = l/2-inch Number of fans a 1 Total flow s 5215 C.F.M. Width of Opening = l/2-inch Number of fans = 5 Total flow a 8650 C.F.M. was then calculated as follows: To determine the amount of air exhausted Figure 38 (Appendix B) The amount Of air exhausted 32 Average velocities at points 1, 2, 3, A, 5, 6, 7, and 8 are: 1067, 1209.5, 897, 784.5, 901, 1260, and 1553.5 feet per minute respectively. Average velocities at points 9, 10, 11, and 12 are 353.5, 582, 861, and 303.5 respectively. Flow for the zone l-2-3—A-5-6—7—8 (Figure 23) 1/8 x n/A x [(34/12)2 — (22/12)2] x (1067 + 1209.5 + 1291.5 + 897 + 78A.5 + 901 + 1260 + 1553.5) 1100 C.F.M. --------------------------- (I) Flow through the zone 9-10-11-12 "/4 x [(22/12)2 - (10/12)2l x l/A x (353.5 + 582 + 861 + 303.5) = A210 C.F.M. -------------------------- (II) Therefore, total air exhausted = (I) + (II) = 5310 C.F.M. Temperature Corrections The readings given by the instrument (potentiometer) were adjusted by applying corrections. The error on any particular day was determined by averaging the deviations of the instrument readings from those given by the half degree certified thermometer and sling psychrometer as follows: 33 July 29, 1965 Instrument Certified Thermometer Readings And/Or Sling Psychrometer Difference Readings 72 68.5 3.5 55 60 5 66 6A 2 60 57 3 72 71.5 0.5 65 62 3 Average error = l/6(3.5+5+2+3+0.5+3) = 17/6 = 3 approximately. August 10, 1965 Certified Thermometer Instrument And/0r Sling Psychrometer Difference Readings Readings 91 87.5 3.5 75.5 71 A.5 91 87 A 76.5 73 3.5 Average error = l/A(3.5+A.5+A+3-5) = l/A(l5.5) = 3.875 = A approximately. 3A September 7, 1965 Another potentiometer was used on this day. The temperature readings obtained with the certified thermometer and sling psychrometer were: Isms? Trussesggmmr 78.5 78 0.5 77.5 78.5 -1 78-5 79 -0.5 77 78 76 70 68 73.5 73.5 73 67 67 Differences from certified thermometer in this second set are: -1 and 0 (certified thermometer) and 1, 2, 0.5 and 0 (sling psychrometer). On average, the difference is negligible and therefore no correction was applied on this day. 35 November 11, 1965 On this day, the potentiometer taken on July 29, and August 10 was used. The readings were: Certified Thermometer W 35 32.5 2.5 60.5 55-5 56 51 5 147.5 42-5 5 ”3 38.5 24.5 61 57.5 3'5 63.5 59.5 ’4 55 50.5 24.5 47.5 “-5 3 43.5 39 “'5 uu ”0 u 63 60 3 56 50.5 5'5 Total 53 Average = A approximately. Relative Humidity,,Entha1py, Humidity Ratio and Specific Volume Enthalpies at various wet bulb temperatures were read from a table (A.S.H.R.E. Guide and Data Book). Relative 36 humidities, humidity ratios, and specific volumes were determined from A.S.H.R.E. psychrometric chart. Air Flow In Lbs. Per Hour Knowing the air flow in cubic feet per minute and the specific volume, the flow in lbs. per hour was determined from Lbs/Hour = C.F.M. x 60 x 1bs./cubic foot. The units of specific volume are cubic feet per pound. Heat Transfer Through Walls Total wall area = (180+A0) x 2 x 8 = 3520 sq. ft. Inside surface coefficient = 1.65 Outside surface coefficient = 6 Conductivity of plywood = 0.80 Conductivity of glass blanket = 3.7 Therefore, Overall heat transfer coefficient l U: 0.61 + €%g% + 3?; + 0.17 = 0.069 B.T.U. per hour per degree F. per square foot U.A = 0.069 X 3520 = 2A3 Heat transfer through the walls = 2A3 x Difference in in- side and outside temperatures. 37 Heat Transfer Through the Ceiling Total ceiling area = 180 x A0 = 7200 sq. ft. Inside surface coefficient = 1.65, i.e. R = 0.61 Outside surface coefficient = 1.65, i.e. R = 0.61 Conductivity of plywood = 0.80 Conductivity of rock wool = 3.70 (Figure 1) Therefore, overall heat transfer coefficient = l = .0413 0.61 + 8480 + 3.7 x 6 + 0.61 U.A = .0413 x 7200 = 297 and heat transfer through the ceiling = 297 x difference of attic and inside temperatures. Heat From Electric Lamps Number of electric lamps in the house = 76 25 watts. Power of each K.W.H./Hour x B.T.U./K.W.H. Because B.T.U./Hour Therefore, heat from the lamps in B.T.U. per hour = 76 x 25 x 1/1000 x 3413 = 6485 B. T. U./Hour. Heat Removed by the Ventilation From the enthalpy difference and the air flow in lbs. per hour: Heat removed by ventilation (see Appendix) - Enthalpy difference x Air flow. 38 Bird Heat Production The day heat production by A lb. white leghorn hens at various temperatures is given by Ota (20) in the form of a chart which gives the values in B.T.U. per hour per bird. From this, heat in B.T.U. per hour was Obtained by multiplying of the number of birds (see Appendix A). Moisture Produced The moisture produced by the birds at various tempera— ture levels is given by Ota (20) in a tabular form. The moisture output from the table was read in lbs. per day per 10 hens. Moisture in Lbs. per hour = Moisture in.lbs. per day per 10 hens x l/2A x number of hens x 1/10. Heat Input and Output Input = Sum of the components adding heat to the house. Output = Sum of the components removing heat from the house (Appendix A). DISCUSSIONS AND FINDINGS Temperature Differentials The inside and outside temperatures are plotted at 5 minutes interval in Figures 22 to 27. These diagrams show that differences in inside and outside dry bulb tempera- tures, and inside and outside wet bulb temperatures are con- stant under similar weather conditions and at the same flow rates. If there is a change in either of the two, the differential changes and assumes a new constant value. The temperature differentials were: --——-— -‘-- Date Time Flow Differential Rate (inside - outside) July 29, 1965 12:45 - 1:15 24660 +7 July 29, 1965 2:35 - 3:05 24660 +5 Aug. 10, 1965 12:00 - 12:30 2A7AO -2 Aug. 10, 1965 1:35 - l:A5 197A0 —3.5 Aug. 10, 1965 3:00 - 3:15 17600 -5 Sept. 7, 1965 2:10 - 2:30 21420 +4 Sept. 7, 1965 3:40 — 4:15 28070 +3 AO mw..mN >15... 20 443mm»; 2.2 n .._.< mas—w... wo.m......o oz< mgmz. NvaE a? .~ E3 .NI 3 no... 93. .EII o a. 1 - I I- I L11II1 ......... -Iou zao omoe~ 1 A on _ 4.. 1 a at 1 11: - _ on 1 -I 33.8.3 _ I 3 352. II on -I 8 mo_mSo.-I I - no usz. I I LEI a. 1 1 I I- III- II 1I 1 1 IIIII on 1 1 1 II I I III II I I1Ii I1. 1;! ,1 1 A1 3.6. one 20 443551.212 n .2 .2sz mango o 3.621 361.. o .. ,. . 1 ME. b .1. I I as.» 61.61 . 1F 1 1 1 1 1 .4 1 1 .51. _ 11 I 1 . 1 1 1 1 1. 1 1 _ _ lo. .. 1 1 1 1 1 1 . a 1 1 , 1 _ 1 1 1 1 .1 1 .I--1 , _ 30:31 1 1 _ 1 1 1 . 4.. A __ 1 1 If I I 1.----I1I III -1. w 1.II12. 1 _ 1 1 1 IlII- I 1 . 1 1 . 1 1.1.]... 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ON 43 t __ z _ _ 0 OBNOEPDO... m3 uo.m2.+ 5 mo wo_mh30§ 4..m.o wo_mz..v W1 on on _ I p - Loo. 2&0 ONOON 2&0 OMEN 1W '10th mm.:>oz zo mmmPEmMQZNP mo_m._.30 024 mez. mm 0.... ow -_ I81! -04... . -9.....--- - 8w... boom. . om. OWN. a; .3850 no mew-v.3: O3 N032. 1”! T .d n 0 No.9: ._-_.... -.___.‘ 7. :3 on.» so... So .~ 2...... no oz "a: 5.2. 00. 1+5 mm... >02 20 na>mm._.z_ 2.2 m ._.< wazm... mew—.30 w mafiz. RN 9...". m3; .lolo_nm a..-» an.» . jun! owP 8- jar LVN-w jo . - _-l . o. -. - 1.- 1 .. Tail-.8 n IIIIIIIEIIIIII we ,3 II" - -_ e, I'll-II.- . _ ‘1 n o ”052. . : -- p — T G / I. I. - - - - l- W W arm Tllll .240 030.. 24... .mhqu. ..N\. X 0 IN: M l. 1.. O 0 3 3 ... J U. I. Z N o A: g V J. N s m H6 The maximum differential for heating is 7 degrees F. above the outside temperature and that for cooling 5 degrees below the outside temperature. If all heat were removed by ventilation as sensible heat, the inside temperature would rise to 72°F., 75°F., 94.5°F., 97.5°F., 102°F., 84.5°F., and 82.5°F. respectively on the date and time mentioned above. The effective eva- porative cooling (difference between these and the actual inside temperatures taking place is then 3, 6, 12, 10.5, 13, 12.5 and 8.5. It is worthwhile to note that the inside wet bulb temperature curve goes parallel to that for outside wet bulb temperature. Heat Balance The heat input and output are shown in Figures 28, 29, 30, 31, 32, and 33. The heat input No. l is based on the total heat production (day only) by a 4 pound bird as reported by Ota and McNally (20), and was obtained by con- ducting a series of studies on 10 laying hens in standard lO-inch wide individual cages in a calometer 7 x 5 x 6 ft. Input No. 2 is based on the average daily heat production per pound of live weight obtained from similar studies by Ota (15). On July 29, 1965 from l2:HO P.M. to 1:45 P.M. (Figure 28) the heat output is equal to input No. l but greater than input No. 2, From 2:35 P.M. to 3:05 P.M. the output a? modNN 20 4<>mm._.z. 2.2 m #4 kaQHDO .m 3.sz NEH—.902 .0 Cum: ¢~0_n_ amusnow 3 o o 9 “£381 15.... .. E LE... OOur 0 ~ 2&0 oowvu . _. _ _ _ was. a finite-v- $-17 iiTlILov _ i . . _ _ _ . _- - i -..- N x W . . _ O L. . l i w i i .l. _ i E. . u M m . i. 8 . . i u __ I. -._ _ .- __ n i , / . , i % f H . . h ___ i a i i _ _\|.||l.| AN. :52. ._.— —.—.__- 49 .mmd. bad 20 3.31.50 6 95¢; bum: ov:n lioLi II. 1 [ sun: 01 nova 3 I l I I i : I f 1 l I l I l l l l UH/nlfl OOOI X 0mg... bu! o-m..~ ov.~ bv; 0.... Onlo on __ 3- . I- 1l1_ M r ,. w - ,i-ITL... \ a. 5...... I/ .3.- ’ I haukaol/ 03 35...... I zl.-r..---.-.. M.-.- L J. m. w 9 V N O N M S O S .. 9 .. mu. Z... m H” w m N 1 ql 3 3 I. l— 50 mmfin—ww ZO 4<>mm._.z. 2.2 m #4 whamhzo 07¢ OOI¢ onun ov-m . _ - .4; w whiz. own m2: 9% ON-~ mm:...m.Os. .m .rdm... 50.“. 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