LI B R.AR.Y OF THE U N IVLR5ITY or ILLI NOI5 69 7 no- 1-3 Co/)- Z The person charging this material is re- sponsible for its return to the library from which it was withdrawn on or before the Latest Date stamped below. Theft, mutilation, and underlining of books ore reasons for disciplinary action and may result in dismissal from the University. To renew call Telephone Center, 333-8400 UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN FEB lO. C f MAR 1 J i:-3 MAR 1 5 ^«l> MAR 3 1 IS8I L161— O-1096 Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/researchprogress03harr X\6.3 ENGINEERING EXP, MECHANICAL ENG l = B = R STEAM hliL}N T STATION DEPARTMENT HEATING RESEARCH :R-3 ™,..fNEERING LIBRARY ^HIVERSITY OF ILLINOIS URBANA, ILLINOIS RESEARCH PROGRESS REPORT 1959-60 THE l=B=R HYDRONIC RESEARCH HOUSE QQU. iHE LIBRARY OF THE OCT 17 1960 yHiVERSilY OF ILLINOIS By WARREN S. HARRIS and ROBERT R. LASCHOBER Sponsored by INSTITUTE OF BOILER AND RADIATOR MANUFACTURERS UNIVERSITY OF ILLINOIS URBANA, ILLINOIS JUNE, 1960 ^f7 EKGINEERING LIBRARY I=B=R RESEARCH PROGRESS REPORT This progress report has been prepared for the use of members of The Institute of Boiler and Radiator Manufacturers only. Its contents are not to be made available to the press or otherwise duplicated without written permission from the University of Illinois. This form of preliminary report is being adopted in order to give representatives of member, associate member and international member companies of The Institute of Boiler and Radiator Manufacturers an oppor- tunity to study results obtained in the I=B=R Research program at the earliest possible datco Since in some instances data are still incomplete or not fully analyzed, all results in these progress reports should be considered as tentative and subject to revision as further data are available. Material in these progress reports will eventually be incorporated in Engineer- ing Experiment Station Bulletins* Constructive criticism of material in this report or suggestions for further study should be sent to the authors at the I=B=R Hydronic Research House, 2103 Zuppke Drive, Urbana, Illinois o Persons whose names appear on the General I=B=R membership mailing list automatically receive a copy of progress reports. A limited number of additional copies of this report are available for distribution to members of the Institute at 50 cents per copy. RESEARCH PROGRESS REPORT - 1959-60 THE I=B=R HYDRONIC RESEARCH HOUSE The research done in the Hydronic Research House during the summer of 1959 and the winter of 1959-60 represented the first experimental work in the new house o It is, therefore, fitting that this report con- tain a brief description of the house and the reasons for building it. The construction and style of a house have distinct effects on the performance of heating and air conditioning equipment. Therefore, it is important that houses used for heating and air conditioning research be representative of current trends in housingo Furthermore, the design of a research home should be such that the more difficult heating and air conditioning problems will be encounteredo On September 5, 1959, ground was broken for the construction of a tri-level house to be used as a laboratory in which to study the per- formance of hydronic heating and cooling systems. Fig. 1 shows the exterior of the house and floor plans are shown in Fig, 2. This new house replaces the two=story I=B=R Research Home which has been used in a similar manner since 194-0. The tri-level house design in itself presents some problems not encountered in the conventional one and two story house construction. Liberal use of glass has been made in the living room. Several types of wall and ceiling constructions are available for study, A minimum of insulation was used in the walls and ceilings since the more poorly insulated houses are the more difficult to heat and cool satisfactorily. To increase the flexibility of the house, all walls were constructed so that they may be opened to make changes in the type and amount of insulation usedo Statistics on the Tri°Level I=B=R R esearch House Floor Area*, first level = U-11 Sq^ Ft. Floor Area*, second level = 592 Sq, Ft= Floor Area*, third level = 569 Sq. Fto Floor Area*, 2 car garage = 560 Sq^ Ft. Floor Area*, equipment room = 90 Sqo Fto Floor Area*, TOTAL = 2288 Sq. Ft, Number of Rooms 10 Number of Baths 2i Wall Construction: 1638 Sq. Ft. First level: Brick veneer on 6=ino light weight concrete block. Inside treatment is 1-inch wood paneling on 2 inch furring strips o No insulation. * Based on inside room dimensions. -2- Second and third levels: Frame with one inch of insulation. Outside treatment is vertical wood siding on plywood sheating, inside treatment is \/U inch plywood paneling. Ceiling construction: Kitchen and breakfast room: Lath and plaster, attic space above two inches of insulation on under side of roof rafters, 3 inch insulation above plaster. Dining room: Acoustical tile, attic space above, two inches of insulation on under side of roof rafters, 3 inch insulation above acoustical tile. Entrance and living room: Acoustical tile, two inches of insulation, no attic space above. Bedrooms: Acoustical tile, masonite, two inches of insulation on under side of roof rafters, no attic space. (Can be modified to provide attic space if desired.) Roof: Asbestos shingles on wood sheating. Two inch x 6 inch rafters were used which left an air space of approximately 3-1/2 inches between the insulation and the under side of the roof sheating. This air space was vented to the outdoors through continuous slots ^-l/2 inches wide extending the fiai length of each soffit. Floors : First level: Four inches of concrete on -4 inches of gravel fill. A U mil polyethylene film between the concrete and fill served as a vapor barrier. Insulation consisted of 1 inch styrofoam located on the inside edge of the founda- tion walls and extending from the floor surface to 2/+ inches below the floor surface. Second level: Asphalt tile, 3/4- in. plywood, 1 in. x 6 in. sub- floor on 2 in. x 10 in. joists located over a crawl space. Vents with closures were provided in the wall of the crawl space so that this space could be used either vented or unvented. The vents were in the open position during the cooling tests. Design loads: Heating: 76,350 Btu per hour at an outdoor temperature of -10 F and an indoor temperature of 70 F. Cooling: 32,335 Btu per hour at a maximum outdoor temperature of 95 F and an indoor temperature of 75 F. -3- Instrumentation Thermocouples installed in and around the house provide for the measurement of the temperature of the indoor air at four levels in each room, the temperature of the air in the crawl space, attic and outdoors; floor, wall and ceiling surfaces; temperature of the ground to depths of 10 ft. both under the house and to the side of the house; driveway and walk surfaces; the temperature of water entering and leaving the boiler and each room heating unit used in the heating system; the temperature of the fluid entering and leaving the heat exchanger and each coil of the snow melting system; the temperature of the water entering and leaving the chiller and each fan coil unit used in the summer cooling system; the temperature of the gasses leaving the boiler, and the temperature of the air entering and leaving the air-cooled condenser used in the cooling system. Recording and indicating flow meters to measure the rate of water circulation in each zone of the heating, cooling and snow melting systems. Clocks to measure the operating time of all electrical equipment included in the svs terns under test. Watt-hour meters to measure the power consumption of all electrical equipment included in the systems under test. CO2 meter for determining the completeness of combustion. Humidity indicators and recorders for measuring the moisture content of the room air and outdoor air. Heat meters to measure the rate of heat transfer through walls , ceiling, etc. COOLING - SUMMER 1959 System Used The initial cooling system consisted of a five horsepower, air- cooled, water chiller and three fan-coil units. The water chiller was located in the equipment room with the boiler while the air cooled condenser was located outdoors at the rear of the house. One fan-coil served each level of the house o The fan coil serving the first level was located at the ceiling of the hall closet. Return air reached the fan-coil through the closet door which remained slightly open throughout the tests. The conditioned air was discharged into a plenum formed by installing a false ceiling in the closets. Registers near the ceiling admitted conditioned air from this plenum into the recreation room and the den. The fan-coil serving the second level was located above the kitchen ceiling. The return air registers were located near the ceiling in the dining room in the partition between the dining room and kitchen. The space between the ceiling and the top of the kitchen cabinets served as a duct to distribute the conditioned air to registers serving the living room, dining room, kitchen and breakfast roomo The fan-coil serving the third level was located above the hall ceiling. The return air was -L- taken from the hall at the ceiling and the conditioned air was supplied to each of the bedrooms through high sidewall registers. Table 1 shows the calculated design cooling loads. These loads were determined by the method contained in the I=P=R Cooling Load Cal- culation Guide Noo C-30j except that no internal load allowance for the kitchen was made in as much as there would be no cooking in the house during the tests. The remainder of the report will cover test results obtained this summer. These will include a discussion of room air temperatures and measured cooling loads. Indoor Air Temperatures The observed average room air temperature 30 inches above the floor was between 73o2 and 75o3 F over the complete range of outdoor temperatiire (Table 2). The average room air temperature 30 in. above the floor of the first and third levels was almost independent of the outdoor temperature. However, for the second level, the average room air temperature 30 in. above the floor increased about 1,U "^ for each 10 F increase in the maximum outdoor air temperature. The relative humidity of the indoor air was about 50 percent all through the summer. The measured cooling capacity of fan-coil 2 was 11,660 Btuh at the operating conditions of this series of tests as compared to a design heat gain of 15,666 Btuh for the second level. Had the capacity of fan-coil 2 been slightly greater j, this slight increase in air temperature could have been avoided. The increase in average air temperature on the second level was too small to affect ones feeling of comfort. During a special test on August 13, air temperatures 30 in. above the floor in each room were recorded each hour. A room by room analysis of these readings indicated that the average difference between the maxi- mum and minimum temperature within any one room during the day was 3o6 F. The smallest difference was 1,6 F in the kitchen, and the largest 7.0 F in bedroom 1 and 6,0 F in bedroom 2. The temperature variations in the recreation room, living room^ and bedroom 3> the rooms in which the thermo- stats were located, were 2.3 F, 3.0 F and 3<.6 F respectively. The large temperature swing in bedrooms 1 and 2 resulted in part from a shift in load from one side of the house to the other from morning to afternoon. The thermostat for the third level was located in bedroom 3» In the morning this room received much more direct sunlight than bedrooms 1 and 2, As a result, the load in bedroom 3 was relatively large in the morning while the loads in bedrooms 1 and 2 were relatively light J but, since the operation of the fan-coil was controlled by the thermostat located in bedroom 3, the temperatures in bedrooms 1 and 2 were reduced to about 71 F during the morningo In the afternoon, when the windows in bedrooms 1 and 2 received direct sunshine, the air tem- perature in all three bedrooms was about the same. To determine the uniformity of temperature from room to room, the air temperature 30 ino above the floor in the room in which the thermostat was located was subtracted from the air temperature 30 in. above the -5- floor in each room on that level. Table 3 shows the results of this type of analysis applied to the data of the test of August 13. The air temperature in all rooms, including bathrooms and lavatories which were not supplied with conditioned air, was within +2.7 and -2,9 F of the air temperature in the room in which the zone thermostat was located. If bathrooms and lavatories are eliminated from the comparison, the extremes of unbalance become +1,2 and -2.9 Fo The greatest degree of unbalance occurred in bedrooms 1 and 2o Since the air temperature in these rooms never exceeded the air temperature in bedroom 3 by more than 0, 7 F even in the late afternoon, it is apparent that a part of the unbalanced condition could have been eliminated by a readjustment of the dampers at the supply registers to divert a greater proportion of the total air flow to bedroom 3„ On the other hand, it must be pointed out that, since direct solar radiation represents a large part of the cooling load, there is bound to be some unbalance in room air temperatures as the solar load shifts from one side of the house to the other from morning to afternoon. Measured Cooling Loads In order to determine the variation in load for each level of the house through the course of a day, special tests were made in which plas- tic curtains were installed at the top and bottom of the stairs to pre- vent air circulation from one house level to another. Hourly readings were taken of the operating times of the chiller and each fan coilj the rate of water circulation through the chiller and each fan coil; water temperatures in and out of the chiller and each fan coil; the air tem- peratures in each room; the outdoor temperature and the power consump- tion of all electric motors. The hourly cooling loads were determined from the measured water flow rates and the water temperature changes. Fig. 3 is a graphic presentation of the loads obtained during the test of August 13. Time of day is indicated along the bottom of the chart and the cooling loads in 1000 Btuh and outdoor temperature are indi- cated on the vertical scales. The maximum outdoor temperature was 92 F and this occurred at about 4.:00 PM (daylight saving time). The first and third levels had windows on the NE, SE and NW sides and hence received direct radiation all morning and late afternoon. Because of the morning sunshine the maximum load for these levels occurred at about 1:00 PM. The bulk of the glass on the second level was on the NW side of the house and therefore the maximiim load on this level did not occur until about ^:30 PM. The actual magnitudes of the measured maximum loads are shown in Table 4., The maximum load on the chiller occurred at 3 s 30 PM and amounted to 29,200 Btuh, The calculated cooling load for comparable indoor and outdoor temperatures using Guide 0-30 is 28,568o The agree- ment between measured and calculated load was equally good for the second level of the house, but for the first level the measured load was almost 13 percent less than the calculated and for the third level it was about 29 percent greater. At the present time it is not certain what caused these disagreements between measured and calculated loads. How- ever, a thorough analysis is being made in connection with a joint study of cooling load calculation procedures being made by I=B=R, National Warm Air and ARI. The report of this analysis will be available in the near future. -6- Measurement of the air flow rate through each supply register was made and the total cooling effect of the fan coil was divided between the rooms in the same proportion as the division of the total air flow. Table 5 shows a comparison of the calculated cooling load of each room and the measured maximum load for the August 13 test. The cooling effect delivered to the dining room was more than twice the calculated load, while the kitchen and breakfast room received less than the calculated amount. Because of the open design of the house, the living room, dining room and entry are in effect one room with a total calculated load of 9,4-00 Btvh which agrees closely to the total measured load of 10,800 Btuh for these rooms. The kitchen and breakfast room also are essentially one room with a total calculated load of 4.j233 Btuh, The measured load for these two rooms was only 2,700 Btuh. In guide C-30 no credit is given for shading resulting from over- hangs except on the south wall. The exposed wall of the kitchen and breakfast room faced the southeast and, therefore, even though the roof overhang was UB in,, all glass and wall areas were treated as sunlit. Actually much of the wall was shaded during most of the day and the sun's rays never fell on any of the glass area in these two rooms. Had the walls and windows been considered shaded, the calculated load would have been 3,173 Btuha The main object of the tests made in the I=B=R Hydronic Research House during the summer of 1959 was to determine the actual cooling loads on the house and to compare them with the calculated loads. As might be expected, differences between measured and calculated loads were observed. For the most part, these differences were not great > but, as was pointed out earlier, they are being carefully studied to see if they might point the way to further improvement of the cooling load calculation procedures. A report of this study will be forthcoming in the near future. HEATING PROBLEMS ENCOUNTERED AT THE I=B=R HYDRONIC RESEARCH HOUSE AS A RESULT OF CEILING CONSTRUCTION Early in the initial heating season at the I=B=R Hydronic Research House it was found that high winds adversely influenced comfort conditions within the house. Deviations from acceptable comfort conditions were most noticeable on the second level, or living level of the house o Roof Construction The roof and ceiling structure for the second level is of the cathedral type as shown in Figo /+A,, In this type construction the ceiling line follows the roof line and outdoor air is free to pass over the insulation and below the roof through the soffit vents on either eave. The method of constructing and insulating the ceiling-roof structure was representative of common practice o Sheathing ^ building paper, and shingles were secured to the rafters by acceptable methods, and the insulating blanket above the ceiling was stapled to the underside of the rafters. The insulation was butted-up against the ceiling beams but was not attached to themo No vapor barrier other than that on the -7- blanket insulation was usedo It will be noted in Fig, ^A. that the interior ceiling of the Research House is composed of acoustical tile attached to furring strips on the underside of the rafters » Comfort Conditions . With conditions of high winds, the comfort conditions of the second level fell far below those considered acceptable. In order to give a clear picture of the conditions which existed on the second level during a windy period, a brief discussion of the data taken during such a period follows » On one particular day when the wind was low and the outdoor tempera- ture was 35 F, comfort conditions within the house were satisfactory with a 30 in. level air temperature of 73 F. During the day the wind velocity increased abruptly as the outdoor temperature gradually fell to 3 F in a fifteen hour period. Almost immediately following the increase in wind velocity the indoor air temperature 30 in. above the floor on the second level of the house started to fall, and within seven hours had fallen to 58 F, During the next seven hours the outdoor temperature increased from 3 F to 18 F while the wind continued to be strong. Through- out this period of increasing outdoor temperature the indoor air tem- perature on the second level climbed no higher than 63 F despite con- tinuous operation of the circulator. As the wind then died, the air temperature 30 in. above the floor gradually approached its controlled setting of 73 F. In addition to observing the room air temperature at the 30 in. level, observations of drafts and air currents in portions of the living room were made by using smoke. In many of the areas where the study was attempted, it was impossible to obtain well defined smoke patterns due to the high velocity of the air currents o This was particularly true in the vicinity of the cracks formed by the junction of the beams and ceiling tile, and when thermocouples were placed near these cracks tem- peratures as low as 8.7 F were recorded for the air entering the room around the beams. Although the second level was the only level to be extremely uncom- fortable, the other two levels became somewhat uncomfortable as they shared in an attempt to carry the increased load. The 30 in. level air temperatures of the first and third level dropped to approximately 70 F despite continuous circulator operation. Steps Taken to Reduce the Effects of Wind Because of the extremely undesirable conditions experienced in the Research House during windy periods, several alterations were made in an attempt to reduce the infiltration rate through the ceiling. First, the open soffits were sealed with plywood covers to prevent air flow above the ceiling. Second, all crackage formed by the junction of ceiling tile and beams was sealed with tape and the tape then concealed by quartern-round stained to match the beams* These two alterations were performed simultaneously and were successful in eliminating the uncom- fortable conditionSo Later in the season the soffit covers were re- moved. VJhen this was done, windy days again produced below acceptable comfort conditions on the second level. -8- Conclusion s and Reco mmenda t ion s 1. The type of ceiling used in the living room of the I=B=n Hydronic Research Hotase and the method of installation are representative of common construction practice in modern homes. 2. This type of ceiling, as normally constructed, may permit excessive Infiltration which will result in hard to heat houses and poor com- fort conditions. This is especially true if acoustical tile is used in place of plaster on the ceiling. 3. Since the I=P=R Hydronic Research House was constructed according to acceptable procedures, it does not seem unreasonable to expect that today there are homes in existance which have been found difficult to heat. It also does not seem unreasonable to expec"^ that in many of these homes the blame has been wrongfully placed on the heating contractor and/or the heating system. 4.. It is essential that architects and builders be made aware of the short comings of this type of ceiling construction and the need of adequate protection against excessive infiltration. 5. The following installation procedure would insure minimum infiltration at only a nominal increase in construction cost. a.. Staple insulation to the underside of the rafters. Joints between insulating batts or blankets should be kept to a minimum and care should be taken when such joints are necessary to make them as tight as possible (that is, the batts should be in good contact all the way across the joist space). b. Apply a vapor barrier over the entire ceiling area. This vapor barrier is important to reduce both moisture and air transfer through the ceilings There must be no unnecessary openings in the vapor barrier and it must be stapled to the rafters, plates, and/or beams so that air cannot pass around the edges of the vapor barrier. See Fig, ^^.B. HEATING - WINTER 1959-60 System Used and Tests Conducted The heating system installed in the tri-level I=R=R Hydronic Research House during the 1959-60 heating season was a three zone, series loop, forced circulation, hot water, cast iron baseboard system. Zoning of the system was done by levels with each level having a thermostat set to maintain 73 F at a distance of 30 inches above the floor. Whenever the air temperature at the 30- inch level fell below the thermostat setting, the thermostat, through a relay, initiated the operation of its zone circulator. Hot water was then circulated through the series loop until the thermostat was satisfied. A gas fired, cast iron boiler was used to heat the water. The boiler water temperature was modulated with variations in outdoor temperature by an outdoor boiler water temperature control. Over the range of opera- =Q« ting temperatures p this control maintained a differential of approximately 60 F between the cut in and cut out temperatures » Early in the program it was found that the intermittent operation of the zone circulators overlapped each other causing fluctuations in both boiler water temperature and water flow rates through the individual zones, making it impossible to determine the heat input to any one zone by using the product of mass flow 5, specific heat and temperature drop of the watero For this reason the system piping was altered for some tests to permit the zones to be isolated from each other in order that each could be provided with its own source of energy o Flectric emersion heaters of sufficient capacity to handle the loads were installed in each zone of the modified system. The operation of these heaters was controlled by the room thermostats o The energy input to each loop was a measure of the level loado The circulators were operated continuously while heating with electricity. Using the input of either electricity or gas as a measure of the actual house heating loads ^ tests were run to determine the loads for several different operating conditions. First of allj a test was conducted using electrical energy as the source of heat input to determine the total house heating load and the individual level loads » For tWs test series nothing was done to prevent transference of load from level to level and the soffit vents on the second level were closed (see section, "Heating Problems Encountered at the I=B=R Hydronic Research House as a Result of Ceiling Construction) A second test using electrical energy was then conducted to determine the effect inter-level load transfer had on the total and level loads* It was assumed that if there was a transference of load from level to level the transfer would occur by the inter=level movement of air. Thus, for this testj, air was prevented from moving from level to level by tightly sealing the staircases joining levels with plastic films o Each of the two films used was provided with a zippered silt which permitted the occupants of the house to move from level to levelo This zippered slit was kept closed at all other times o Following the tests made with electrical energj' input p tests were conducted using gaso The house conditions for the initial gas test were identical with those for the last electrical teste, namely 5, the levels were isolated with plastic films and the roof soffits of the second level were closed o This test was conducted mainly to compare the measured loads derived by use of gas with those derived by use of electricity, AlsOj, it made possible the comparison of fuel efficiencies o The final test was conducted using gas as the source of input energy. For this test the plastic films between levels and the plywood soffit vent covers on the second level were removedc The objective of this test was to determine the effect that the soffit vent covers had on the total heating load. Table 6 is a tabulation of the tests conducted in the I=B=R Hydronic Research House for the 1959'=60 heating seasono The table includes the test series number and the fuel used along with the house conditions for each testo -10- Effect of Wind on Measured House Loads The actual heating load of a building varies with the indoor- outdoor temperature differenceo To determine this variation for the I=B=R Hydronic Research House, the total energy input was plotted against the daily average indoor-outdoor temperature differenceo When this was done, the lack of correlation in the plotted points indicated that the fuel con- sumption was affected by some other variable in addition to indoor-outdoor temperature difference^ Further analysis of the data revealed that the daily average wind speed also influenced the fuel consumption, and the combined effect of indoor-outdoor temperature difference and wind speed gave a better indication of daily fuel consumption o The effect of wind speed was obtained by grouping the data by ranges of wind speed and then plotting the data on coordinates of average indoor-outdoor temperature difference and daily fuel consumption. By doing this, it was possible to determine the percentage increase in fuel consumption per 1 mph increase in wind speed for any average indoor-outdoor temperature difference. Also, this procedure made it possible to correct values of observed fuel con- sumption at any wind speed to the wind speed being investigated. For the test series conducted with electrical energy as the source of input the total measured load, based on the measured load at mph, increased at a rate of 2.3 percent per mph increase in wind speed. For the gas series tests the increase in measured load, based on the measured load at mph, was 3.7 percent per mph increase in wind speed. Thus, the total measured load of the research house could be expected to be in- creased by approximately 3 percent over the measured load at mph wind speed for every increase in wind speed of one mile per hour. Tests at the original Research Home indicated an increase in load of approximately 1 percent per mile per hour. Effect of Air Circulation and Wind Direction on Level Load Distribution Figures 5 and 6 are plots of the total daily input energy vs. the daily average indoor-outdoor temperature differential for three wind speeds for the first two test series. From these figures it can be seen that isolating the levels had no effect on the measured total loads. The effect that isolation of levels had on the level loads can be seen in Table 7. Table 7 is a tabulation of the percentage that each level contributed to the total load for each of the test series determined from conditions of zero wind speed. Also, table 7 includes a tabulation of the percentage change in level load based on test series L-59, when the levels were not isolated. The above comparisons show that for any given indoor-outdoor conditions isolating level loads had comparatively no effect on the total loads but did noticeably influence the contributions which the level loads made to the total 9 Table 7 clearly shows that isolating the levels had the greatest effect on the portion of the total load carried by the third level. Under conditions of isolation, the third level load increased by 37<.3 percent while the first and second level loads decreased by 15*3 percent and 6,4- percent respectively. These changes can be attributed to the warmed lower level air rising to the third level and partially carrying its load when no impedance to air flow was encountered. „11= Isolation of levels had a measurable effect on the distribution of level loads. For test series L-59 (levels not isolated) j the distribu- tion of level loads remained approximately the same for various wind speeds. However, for test series M-59 (levels isolated), it was diffi- cult to assign a fixed percentage to the level contributions over the range of wind speeds because the level loads were greatly influenced by wind direction. In Table 8 the distribution of level loads is tabulated for two test days for which the predominant wind direction was substantially different o In general the pattern of load distribution for easternly and westernly winds followed that given in Table 8 throughout test series M-59. Since this dependancy of load distribution on wind direction did not exist in series L-59j it is obvious that it was primarily caused by the prevention of air interchange between levels* An explanation for the load distri- bution change can be made if one assumes that it is caused by outdoor air infiltrating into the building on the windward side and room air exfilt rating on the leeward sideo If this is assumed^, then the air in the rooms on the windward side would tend to be cooler than those on the leeward side, and a thermostat placed on the windward side of the building would require more heat input to be satisfied than one placed on the lee- ward sideo At the I=B=R Research House, the second level thermostat is located on the westward side of the building, while the third level thermo- stat is located on the eastward side of the buildingo Thus, westernly winds tend to increase the input requirements of the second level and easternly winds increase the input requirements of the third level <> Apparently without the curtains in place the quantity of interlevel air change and mixing was sufficient to offset the effect wind had on the distribution of level loads „ Effect of Fuel Used on Total Load Test series N=59 was conducted in the same manner as series M=59 with the exception that natural gas burned in a boiler was used as the source of input energy in place of the electrical resistance heaters » Figo 7 is a plot of the fuel consumption vso average indoor-outdoor temperature difference for three wind speeds* This figure shows that fuel consumption increased with increased indoor-outdoor temperature differences and wind speedo Before being able to compare the actual heat input to the I=B=R Research House for the two fuels used, it was necessary to determine the percentage of the total input energy which was utilized in each fuel in off-setting the house heat losso In Figo 8 curves 1 and 2 represent the gross input of the electrical and gas energy, respectively, (converted to Btuh) for test series M°59 and N-59 at a wind speed of 5 mpho A 5 mph wind speed was selected for this comparison because the majority of data was collected at approximately this wind speedo In Urbana the heating value of natural gas for the 1959-60 season was 976 Btu per cu, ft., and this value was used to convert the danly gas consumptions to Btuho Electrical energy inputs in Kw Hr were converted to Btuh by use of the conversion factor 34-14- Btu per Kw Hre -12- To determine the utilization of enorgy for the system when gas was used, it was assumed that the only loss in the available energy from the fuel was due to the escape of chimney gases. The heat loss of the chimney gases is composed of two portions: first, the sensible portion which is the result of discharging the flue gas at a temperature in excess of the house temperature, and second, the latent portion which is the result of dischargingthe non-condensed water vapor in the flue gases. In order to determine the rate of flow of flue gases, a Thomas Meter was installed in the chimneyo The Thomas Meter was composed of a heating element made up of a grid of fine ni chrome wire and a temperature dif- ferential thf^rmopile. In operation the energy supplied to the heating element (approximately 110 watts) resulted in a temperature rise (approxi- mately 3.5 F) of the flue gas as it passed across the element. Knowing both the input energy and the temperature rise and assuming the specific heat of the flue gas to be Oo24. Btu per lb. ^, it was then possible to calculate the rate of flow of the flue gas, V^ith the instrumentation used, it was possible to measure instantaneous flue gas flow to an accuracy of approximately 1 percent. Having obtained a flue gas flow rate, the sensible heat discharged from the building was calculated using the equation Hs = W Cp (tc - ti) where : Hs = Sensible heat loss from the building. W = Flue gas flow rate in Ibs/Hr. Cp = Specific heat of flue gas = 0.2^ Btu per lb, °F tc = Average temperature at the second level ceiling line, ti = Average indoor temperature = 73 F, The latent loss was calculated using the equation Hl = 0.09 Wg H2 (he - hf^) where : Hl = Latent heat loss from the building. Wcr = Wt of gas burned, Ib/Hr Hp = Hydrogen in fuel, percent by wt» For methane = he = Fnthalpy of superheated steam at temperature te and partial pressure of 2 psia, Btu per lb. hfi = Enthalpy of liquid at temperature ti, Btu per lb. = Time, hours. In Fig. 8 the sensible and latent chimney heat losses are represented by curves 3 and 4- respectively. =13= In addition to receiving heat energy from the input fuel, the house received heat energy from the occupants, the use of electric lights and appliances, and a gas water heater o The amount of heat that these sources supplied to the house was obtained by determining the daily averages of the occupancy, electrical consumption j, and the water heater gas consump- tion and converting these to hourly averages o The heat equivalents applied to each of these sources of energy was as follows: Occupancy =500 Btu per man hour Electricity -> 34-1^ Btu per Kw-Hr Gas = 976 Btu per cu fte The energy supplied by the occupants and electricity was considered to be available as useful heato Since the water heater was vented through a chimney, it was assumed that only 75 percent of its input energy was available as heat within the house » The hourly average internal input determined in this way was found to be 54^5 Btuh« In Fig. 8 this value has been added to curves 1 and 2 to obtain curves 5 and 6 which represent the total heat input to the house for the electrical and gas series respectivelyo The actual heat loss from the house under any conditions is equal to the net heat inputo Or stated differently i, it is equal to the total heat input less the losses in the total inputo For the gas series test, it was assumed that the losses resulted only from the discharge of flue gases 5 and curve 7, the actual house heat loss, was obtained by subtracting curves 3 and 4- from curve 6o In Fig, 8 it can be noted that the curve for the total heat input for the electrical series, curve 5, is slightly higher than the actual house heat loss, curve 7o In fact, if the total heat input for the electrical series is corrected to an efficiency of 97 percent, which would not be unreasonable since the electric emersion heating sections of the piping were uninsulated, perfect agreement for the actual house heat loss would exist for both the electrical and gas series tests o These data indicate that the house efficiency, which is defined as the ratio of the actual house heat loss to the total input, to be 97 percent for the electrical test series and 80 percent for the gas test serieso The calculated heat loss of the Research House is 76,350 Btuh at an indoor-outdoor temperature difference of 80 Fo Since the calculated heat loss is based on a wind speed of 15 mph, it was necessary to correct the actual house heat loss given in Figo 8 for a 5 mph wind to the actual house heat loss at a 15 mph wind before comparison of the actual and calcu- lated house heat losses could be madeo The actual house heat loss for a 15 mph wind at an indoor=outdoor temperature difference of 80 F was found to be 87,500 Btuho Thus, the actual house heat loss at design conditions was 14-0 5 percent higher than the calculated house heat losso Effect of Open Soffit Vents on Total Loads Series P=59 was conducted in the same manner as N-59 with the exception that soffit covers of the second level roof were opened for series P-59. Figo 9 is a plot of the fuel consumption for various indoor-outdoor tem- perature differences and two wind speeds. Comparing Figs. 7 and 9, it can be seen that removal of the soffit covers resulted in an increase of the fuel input of approximately 9 percent o In addition to increasing the load, the removal of the soffit covers resulted in reducing the comfort conditions within the house on windy days* Effect of Sun From the data collected during the 1959-60 season, it was not possible to make a quantitative analysis of the sun's effect on heating loads and house comfort conditionSo However, observations of room air temperatures and system performance did give a general indication of the effect of the suno On clear days, shortly after sunrise and throughout the morning, the air temperatures in the rooms in the eastern portion of the house would rise above those in the western portion y while during the afternoon the op- posite occurred. The thermostats for the first and third level were located in the eastern portion of the house, and on clear sunny mornings the elevated temperatures in that portion resulted in little or no circulator operation. Consequently J the temperatures of the rooms having a western exposure fell below the thermostat settingo Then in the afternoon, as the rooms in the eastern portion cooled and circulator operation was resumed, the sun effect caused the temperature of the rooms having a western exposure to be in excess of the thermostat settingo The thermostat of the second level was located in the western portion of the house which resulted in the tempera- ture of the rooms in the eastern portion of this level being above the thermostat setting in the morning and below in the afternoono COMFORT CONDITIONS = HEATING Effect of Test Conditions In Table 9 the air temperature gradients are given for each level for the tests conducted. It can be noted that with the exception of the 3"-30" temperature difference for the third level at an 80 F indoor-outdoor tem- perature difference, the maximum deviation of temperature difference between tests at any measured point indicated is of the order of 0,5 to 1.0 F. For the third level the 3"=.30" temperature differences for test series M"59 and N-59 (levels isolated) are large in comparison with those of test series L=59 and P=59 (levels not isolated). The cooler air tem- peratures near the floor on the third level for test series M-59 and N-59 indicate that outdoor air infiltrating into the level collected near the floor and was prevented from spilling down to the lower levels by the polyethylene films. .15^ Table 10 compares the floor and ceiling surface temperatures for each level for the tests conductedo From this table it can be seen that the temperature of the second level ceiling was significantly cooler for test series P=59o This could be expected^, for in test series T-59 the soffit vents of the second level were opened , thus permitting outdoor air to flow above the ceiling o Table 10 also shows that the floor and ceiling temperatures of the third level were significantly cooler for the tests conducted with the levels isolated by plastic filmso It has already been pointed out that the cooler floor temperatures were caused by the plastic films preventing the cooler air of the third level from spilling down into the lower levels o The cooler ceiling temperatures of the third level can be attributed to a change in the pattern of infiltration for this level caused by the plastic filmSo Throughout the series conducted with the films in place, it was observed that the film isolating the third level from the other levels was always bowed toward the third levels indicating a lower pressure on the third levelo Several measurements were made of the pressure differential across this film and it was found that the pressure on the third level was generally in the order of OoOl ino H2O below the second levelo Thus, without the films in place air probably infiltrated in the lower levels and exfiltrated from the third levelo resulting in warmed air exfiltrating through the third level ceilings while with the films in place y the driving force for exfiltration from the third level was reduced considerably and air infiltrated through the third level ceilingo Effect of Wind With the exception of test series P-59J) wind speed did not measureably effect comfort conditions in the research houseo For test series P=59 the soffit vents on the second level were open and high winds resulted in air infiltration into the house through the ceiling of the second levelo On several days this air infiltration resulted in below acceptable comfort conditions on the second level as air temperatures fell below the thermo- stat setting despite continuous circulator operation o The temperature balance in the research house was seriously affected by wind directiono Table 11 summarizes the effect that wind had on the temperature balance on each levelo In the second column of Table 11 the maximum differences in air temperature 30 ino above the floor between the room where the thermostat was installed and any other room of the level are given for a mph windo In this column and throughout Table 11 positive differences indicate temperatures in excess of the temperature in the controlled room 5 while negative differences indicate the contraryo This table clearly shows that wind direction greatly influenced temperature balance and suggests that better balance may have been realized if zoning had been done by orientation o -16" COST OF OPERATION An analysis of the operating expense for both electrical and gas heating was made for test series M-59 and N-59o The analysis was made by using the winter statistical outdoor temperature distribution for Urbana and the values of input determined from the 5 mph curves in Figs» 6 and 7. For this analysis an indoor temperature of 73 F was used. In Table 12 the calculated values of the energy units required to heat the Research House for one season are given for both the electrical and gas input series. In Table 12 the seasonal power consumed by the circulators is also given. Table 12 can be used to compute the cost of operation in any area by applying the cost of the unit energy in the particular area concerned to the values given in the table. For example, in the Urbana area the cost per Kw-Hr for an individual on a demand load basis is approximately 2o5 cents per Kw-Hro Thus the seasonal cost of heating electrically would be (43,290 + 1563) X $0,025, or $1121 o 33 » The unit cost of gas in Urbana is 6^ cents per therm, and the cost of electricity is approximately 3.5 cents per Kw-Hr to the individual not on a demand load basis. Thus, the seasonal cost of heating with gas would be 1810 x ,065 + 72.85 x.035, or $120,20, ■17- Table 1 CALCULATED COOLING LOADS I=B=R HYDRONIC RESEARCH HOUSE Maximiom Outdoor Temperature = 95 F Indoor Temperature = 75 F Room First Level External Heat Gain Btuh Internal Heat Gain Btuh Total Sensible Gain Btuh Bedo 1 Bedo 2 Bed, 3 Lavo A Lav. B Bath Hall 1325 1875 2000 50 1000 175 125 1325 1875 2000 50 1000 175 125 Latent Heat Allowance Btuh U2 625 666 17 333 58 k2 Total Cooling Load Btuh ReCo 2925 300 3225 1078 2,303 Den 1800 300 2100 700 2800 Bath 625 625 208 833 Hall 00 7936 Second Level / LiVo a75 a75 1392 5567 Din. 1650 1650 550 2200 Kitch. 1900 300 2200 733 2933 Breakfast 1150 300 U50 l,ZJ> 1933 Entry- 2275 2275 758 15666 Third Level 1767 2500 2666 67 1333 233 167 8733 Total 32,335 -18- Table 2 AVERAGE INDOOR AIR TEMPERATURES August 8-20, 1959 95% Confidence Maximum Outdoor Air Temp, 85 90 95 100^* 1st Levels 30" Above Floor 73«5+0o2 73.6+0,2 73.7+Oo^ 73.8+0,6 2nd Levels 30" Above Floor 73o2+0a2 73.9+Oo2 7^^.6+0.^ 75.3+0.7 3rd Level, 30" Above Floor 7^o4+0,l 7^oCH:0.2 73.7+0./^ 73c/^+Oo6 * Extrapolated beyond range of data. Table 3 ROOM TEMPERATURE BALANCE August 13, 1959 Time of Day 6 AM 10 AM 2 PM 6 PM 10 PM Differences in Room Air Temperatures 30 In, above the Floor, F First Level Den - Reco Room -Oo9 0o2 -Oo6 -2,0 -0,7 Bath - ReCo Room 0,5 0„2 2c7 0„3 0,2 Second Level Dino - Livo Rmo 0.2 -Od -0,2 -0.6 -0.2 Kitchen ° Liv, Rm, OoO -0o2 0,2 -0,5 1,1 Breakfast Rm, - Liv. Rm, 0,3 0,2 1.2 -0.7 -0.5 Entrance = Liv, Rm, 0.4. 0.4. 1,2 -1,6 0.9 Third Level Bed Rm, 1 - Bed Rmo 3 -0,3 Bed Pm„ 2 - Bed Rm. 3 "Oo6 2,9 -1,5 0.5 -0,1 lo7 -1,1 0.7 -0.3 -19= Table A COMPARISON OF MEASURED AND CALCULATED COOLING LOADS Location Time of Observed^ Calculated*^* Maximim Load Maximum Load Maximrmi Load Btuh Btuh First Level IsOO PM 6,300 7,201 Second Level AsOO PM 13,900 13,633 Third Level IsOO PM 10,000 7,73^ House 3;30 PM 29,200 28,568 * Maximum outdoor temperature = 92 F, Indoor temperature =• 74- F, *^ Maximum outdoor temperature •= 90 F^ Indoor temperature - 75 F« Table 5 DISTRIBUTION OF TOTAL COOLING LOAD BY ROOMS Test of August 13? Room Reco Den Bath 1 TOTAL FIRST LEVEL Livo Dino Kitcho Bro Rmo Entry TOTAL SECOND LEVEL Bedo 1 Bedo 2 Bedo 3 LaVo A Hall * B & Bath 2 TOTAL THIRD LEVEL i9 = Maximum Load 3;30 Po Mo Daylight Savings Time CFM at Supply Total Measured Cooling Load** Btuh Total Calculated Cooling Load* Btuh 169 113 3,780 2,520 3,867 2,567 767 282 6,300 7,201 170 139 31 U9 5,9.^0 4., 860 1,080 1,620 ^,900 1,800 2,533 1,700 2, 700 389 13,500 13,633 99 105 2U 2,230 2,320 ^,750 1,667 2,267 2,^33 1,267 100 418 9,300 * Maximum Outdoor Temperature ** Maximum Outdoor Temperature 90 F 92 F 7 J 734 =20= Table 6 TEST SERIES AND HOnSE CONDITIONS FOR 1959=60 HEATING SEASON TEST SERIES INPUT FUEL LEVELS ISOLATED 2ND LEVEL SOFFIT VENTS CIRCULATOR OPERATION L=59 Electricity No Closed Continuous M-59 Electricity- Yes Closed Continuous N-59 Gas Yes Closed Thermostatically Controlled P=59 Gas No Opened Thermo s tat i cally Controlled Table 7 EFFECT OF ISOLATING LEWLS ON LOAD DISTRIBUTION Level Load in Perce Not Isolated jnt of Total Isolated Percentage Change Level Load 1st 33o2^ 28o3 =15 3 2nd 4.2oo 4O0O »6,4 3rd 23o8 31o7 +37c3 Table 8 EFFECT OF WIND DIRECTION ON LEVEL LOADS FOR CONDITIONS OF ISOLATED LEVELS (SERIES M-.59) Wind Direction E W Wind Speed 806 9oil Level Load in Percent of Total 1st 2nd 3rd 2606 26o5 3I0O U2.U 33ol -21- Table 9 AIR TEMPERATURE GRADIENTS FOR TESTS CONDUCTED ^0° Indoor-Outdoor AT 80° Indoor-Outdoor AT 3" Below 3" Below 3" Below 1st Level 3"-30" 60"-30" Ceil-30"<* 3"-30" 60"-30" Ceil-30" } ' UJ CO D O I I o a: < UJ q: u O q: II o GARAGE t THEK'^OCOjPL-E WEl-L I 1 KADJATOR 22 of= "7 -PRJM C«A^«- SPACE .Df^P DOWN TO J T i ne, H^ ,^ CRAWL SFWCr - _ LIVING ROOM -/ L \ KITCHEN BREAKFAST 3' °f '■? ,' ^TO CPAwv. SPAC EN-^RY 1 n ,' t 3'of •? L_._n^ FROM BouE^^ ^^^ y / TO e3ll_ER rm/ t^ECeSSED SMALL TUBS RAD'ATOR F/RST ~^OOR $ UPPER -EVEL PLAN UN EXCAVATED ClRCULATlNia Pump O C-ONTROL. VALVE (V) SauABE MEAD COilK. ^ BASHBOAPD ■t TH&R.t>->OCOUPLE WELL / ELBOW METER -I V CONOEMSER I RECREATION ROOM ■^ BATH 1 b'OF'l '^ U 1- LOWER LEVEL PLAN FIS. 2 NEW I=B'R RESEARCH HOME 1 1 / // -ZI 1 1 / 1 // « -I 1 r i y / A / f / / / / J / LEVEL COIL / 1 / / ■2ND FAN LEVE COI / / \ ■4 i^ / ^IST LEVEL FAN •* ft 2- 1 1 \ \ { K Ui _l w K^ z o ^ ^ - \ \. \\ a> m m 6 < \ DU) Ol- \ X, 1 < « \ \ \ ^ k ^ \ \ \ \ ^ m UI o n a o > U X > K U K "" i, O M 000 a « 1^ • J- •■ • UJ CO _l Z o » laJ UJ ^^ O UJ 0. CO UH-MM NI N0lldnnSN03 tl3MOd AIIVQ VAPOR BARRIER SECURED TO RAFTERS AND BEAMS PRIOR TO FURRING 5TRIPS PU5H FURRING STRIPS- TI&HT A&AIN5T BEAMS B. A5 RECOMMENDED Fig, 4 Cathedral Roof Construction Details