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274 CHAPTER 14 . 1946 Guide mission heat losses of 20.9 per cent are-relatively small. The infiltration losses (12.8 per cent) are also comparatively small in this case because the storm windows serve substantially the same purpose as weatherstripping. In this problem, the wall, ceiling and floor transmission losses comprise 66.3 per cent of the total. Example 6. Calculate the heat loss of residence shown in Fig. 2 based on the same conditions as in Example 5 but having construction improved or insulated to obtain coefficients as follows: Walls, 0.13; Walls of Dormer over Garage,-0.12; Attic Walls, 0.28; Walls Adjoining Garage, 0.18; Basement Walls (Recreation Room), 0.10. Roof, 0.53. Ceiling {Second Floor), 0.15. Windows (Same as in Example 5). Floor {Bedroom D), 0.18. ` Solution: The procedure for calculating the heat losses is similar to that' for. Example 6. A summary of the results is given in Table 6. Table 6. Summary of Heat Losses of Insulated Residence Heat losses given in Btu per hour - Room or Space Walia CsoiNQ and-Roof - Floor Glass and Door Infiltration Totals t , Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 Living Room Dining Room . Kitchen Lavette Entrance Hall` Garage Recreation 2670 1750 1280 1320 340 820 3580 1860 . . 1400 1460 440 --400a 840 Totals 17,360 Percentages 31.9 2370 1570 1170 1170 540 . 340 __ 850 . -- .8,010 14.7 ... _6_90' 220 , . .. ' .______ ___. .... . -1190b 570 290 0.5 1440 1440 970 720 *500 320 1800 3880 950 1100 640 3410 720 17,890 32.8 i 1010 1010 500 500 500 . ' 420 1120 870 760 - 530 ' 560 2700 490 10,970 20.1 7,490 5,770 3,920 4,400 1,880 2,120 6,500 6,610 3,110. 3,090 2,490 4,520 2,620 54,520 100.0 "Wall loss of 1050 Btu minus gains of 590. 320 and 540 Btu. bHeat gains; 690. 220 and 280 Btu. c "i .:] REFERENCES > 1--An Analysis of Winter Temperatures for,One Hundred and Twenty Cities, by Clark M. Humphreys. (Carnegie Instituteof Technology Bulletin). *--Investigation of Oil-Fired Forced Air Furnace Systems' in the Research Residence, by A. P. Kratz . and S.-Konzo (University of Illinois Engineering Experiment Station Bulletin No. 318). ' *--A S H.V.E. Research Report No. 1011--Tests of Three Heating Systems in an Industrial Type of Building, by G. L. Larson. D. W. Nelson, and John Janies (A.S.H.V.E. Transactions, Vol. 41,1935, p. 185): 4--Methods of Moisture Control and Their Application to Building Construction, by F. B. Rowley. A. B. Algren and C. E. Lund. University of Minnesota, Engineering Experiment Station Bulletin. Na 17).' - A S H.V.E, Research Report No. 1213-1;-Heat Loss Through Basement Walls and Floors, by F. C: Houghten. & I. Taimuty, Carl Gutberlet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48. 1942, p. 369). . '` .* --Measurements of Heat Losses from Slab Floor, by R. S. Dill. W. C- Robinson and H. E. Robinson (U. S. Department of Commerce, National Bureau of Standards. Building Materials and Structures Report BMS 103). . . .. ' * Heat Requirement Tables for Intermittently Heated Buildings. (Engineering Experiment Station Bulletin, No. 60. A. and M. College of 7Yxos.'College Station. Texas), contains a set of tables applicable to either intermittent heating or cooling. Further information may be found in a paper. A Method of Coni- .. piling Tables for Intermittent Heating, by Elmer G. Smith (A.S.H.V.E. journal Section, Healing, Piping and Air Conditioning, June, 1942, p.-386). , ' ' * i- mm Design Outside Temperatures, Components of Heat Gain, Normal Heat Transmission, Solar Heat Transmission, Solar Radiation Through Glass, Heat Introduced by Outside Air, Heat Emission of Appliances, Moisture Through Walls LOAD calculations for summer air conditioning are more complicated than heating load calculations. Due to the variable nature of some of the contributing load components and the fact that they do not neces sarily impose their- maximum effect simultaneously, considerable care must be used in determining their phase relationship. The conditions to be maintained in an enclosure depend upon several factors, especially the outside design conditions, duration of occupancy, and relationship between air motion, dry-bulb and wet-bulb temperatures! Information concerning the proper indoor effective temperature to be maintained is given in Chapter 12, for different geographical locations' and for various age groups of individuals. Typical commercial design room conditions for the summer average peak load are shown in Table 1. Summer dry-bulb and wet-bulb temperatures of various cities are given in Table 2. The temperatures are not the maximums but the design tem peratures which should be Used in air conditioning calculations. The maximum outside wet-bulb temperatures as given in Weather Bureau reports usually occur only from 1 to 4 per cent of the time, and because they are. of such short duration it is not practicable to design a cooling system for them. The temperatures shown in Table 2 are based on available design conditions known to be applied successfully.. . COMPONENTS OF HEAT GAIN A cooling load determination is composed of five components which are classified in the following manner: 1. Normal heat transfer through windows, walls, partitions, doors, floors, ceilings, etc. 2. Transfer of solar radiation through windows, walls, doors, skylights, and roof; 3. Heat emission of occupants within enclosures. 4. Heat introduced by infiltration of outside air and controlled ventilation. 5. Heat emission of mechanical,. chemical,. gas, steam, hot water, and electrical appliances located within enclosures. The components of heat gain; classified by source, are further classified as sensible and latent heat gain. - The first two components fall into the classification of sensible heat gain, that is, They tend to raise the temperature of the air within the structure. The last three components not only produce.sensible heat gain but they may also tend to increase the moisture content of the airwithin-.the structure. Normal Heat Transmission i By normal heat transmission; as distinguished from solar heat trans mission, is meant the transmission- of heat through windows, walls; ^partitions,.etc. from without to interior of enclosure by. virtue of difference between outside and inside air temperatures. Since the daily range of