Document OEBzXLmn2pxYZjJJk3BjEDxxp

246 CHAPTER 11 1950 Guide Notes fob Table 5. * The inside-oatside temperature difference is 70-- (--10) or 80 F except where otherwise noted. b Volume of infiltration, cfh = (no. air changes) x (floor or ceiling area) x (ceiling height). c From Equation 5a. d The heat Iwws are calculated by estimating the attic temperature and then calculating the loss through the ceiling using the proper temperature difference. This unheated attic is not ventilated during winter months. The attic temperature is estimated from Equation 1 to be 30.2 F when the outside tem perature is -- 10 F and room temperature is 70 F. The temperature difference is then 70--30.2 or 39.8 deg. For the insulated raidenoe, attic temperature becomes 4.6 F and temperature difference 70--4.6 = 65.4 deg. " Temperature in garage asumed to be 35 F. 1 Coefficient for wall ***joining garage calculated on basis of metal lath and plaster on both sides of studs. (U - 0.39). One half of value from Table 4. Chapter 10, for storm windows or weatherstripping. h Exposed on two sides, weatherstripped windows offset by fire-place. Use 1}. 1 Window on one side weatherstripped but double-doors are hard to close tightly. Hence, conservative, value of 1}. i Awnuming kitchch vent, door to vestibule usually open, allow full table value of If. k One-half value in Table 4, Chapter 10, increased to 1} by nearby outside door in vestibule. 1 Full value in Table 4, Chapter 10, to allow for frequent opening of outside door. m Two aides exposed, large doors but large volume. Use value 1} as given in Table 4, Chapter 10. Two unweatherstripped windows in protected location, but fireplace, indicate 1 change. Since g*r*g is oolder than ground, heat gain results should be subtracted from heat losses p Heat losses from these rooms into garage are heat gains for garage. Q Neglect heat loss to basement, as losses from boiler, piping, etc., will probably keep basement near, if not above, 70 F. r Upstairs hall w1inp figured with downstairs. Heat should be provided downstairs for both. TiPi.w 6. Summary op Heat Losses of Uninsulated Residence (Btu Per Hour) Room or Spacb Recreation Percentages* Walls 5330 3490 2560 2650 670 1640 7260 3720 2850 3000 870 -1030* . 840 33.850 33.850 38.6 CaatNG AND . Roof 6610 4660 . 3540 . 3020 1510 960 . 2390 rl270*> . .------- . 21.720 21;720 24.8 - Floor , 960 310 , -280* 570 1.560 1.5G0 1.8 Glass and Door 1440 1440 970 720 500 . 320 1800 3880 950 1100 640 3710 720 18.190 18.190 20.7 Infil tration 2180 1470 1260 950 630 400 5400 3080 2300 550 1600 1910 2890 24.620 12.310 14.1 Totals 15.860 11.060 8.300 3.310 3.630 14,460 10.680 4.650 5.50U 3.040 5.020 99.940 87.630 * Wall hwt l^wi of 3110 Btuh minus wall heat gains of 1280, 700 and 1160 Btuh. b Heat gains of 960,310 . Btuh. e Heat gain, Based on M computed infiltration. * Based on operating totals. Table 7. Summary op Heat Losses or Insulated Residence (Btu Per Hour) Room or Space Living Roam Recreation Operating Tdtals* Percentages* Walls. 2480 1620 1190 1230 310 7603370 1730 1320 1390 410 ` -470* - 840 16.180 16.180 29.4 ` Ceiling and Roof 2460 1660 1260 1080 540 250 : 850 -----910* . 7.190 7.190 13.0 Floor . 690 220 . -280* 570 1.200 1,200* 2.2 Glass and Door 1440 1440 970 720 500 320 1800 3880 950 1100 640 3710 720 18.100 . 18.100 33.0 Infil tration 2180 ' 1470 1260 950 630 400 5400 3080 2300 550 . 1600 1910 2890 24.620 12.310 . 22.4 Totals 8.560. 6,190 . 4.680 4.670 1.980 1.950 10.570 . 8.690 4.570 3.040 3.500 3.960 5.020 67.380 55,070 10Q.0 Heating Load 247 wind velocity. Inside temperature from Table 2 is assumed to be 70 F. The attic is unheated. Assume ground temperature to be 50 F (see Fig. 3, Chapter 34) under basement and garage floors and 32 F adjoining basement walls. Estimate infiltration losses by the air change method. No wall, ceiling or roof insulation is to be con sidered in this problem, but all first and second floor windows, except in the garage, are to have storm'sash. The building is constructed as follows (heat transmission coefficients U are in parentheses): WcUU: Brick veneer, building paper, wood sheathing, studding, metal lath and plaster (0.28). Walls of dormer over garage, same except wood siding in place of brick veneer (0.26). Attic Walls: Brick veneer, building paper, wood sheathing on studding (0.42). Basement Walls: 10 in. concrete (0.10). Roof: Asphalt shingles on wood sheathing on rasters (0.53). Ceiling (Second floor): Metal lath and plaster (0.69). Windows: Double-hung wood windows with storm sash (0.45). Steel casement sash in basement (1.13). Floor (Bedroom D): Maple finish flooring on yellow pine sub-flooring; metal lath and plaster ceiling below (0.25). Floor (Basement and Garjage) ' 4 in. stone concrete on 3 in. cinder concrete (0.10). Solution: The calculations for this problem are given in Table 5, and a summary of the results in Table 6. The values in column F of Table 5 were obtained by multi plying together the figures in columns C, D, and E. The heat losses are calculated to the nearest 10 Btu. See reference notes for Table 5 for further explanation of data. Attention is called to the summary of heat losses (Table 6) for the uninsulated resi dence. As storm windows are used in this instance the glass and door transmission heat losses of 20.7 per cent are relatively small. The infiltration losses of 14.1 per cent are also comparatively small because the storm windows are equivalent to weatherstripping. In this problem, the wall, ceiling and floor transmission losses comprise 65.2 per cent of the total. Example 6. Calculate the heat loss of residence shown in Fig. 3 based on the same conditions as in Example 5 but having construction improved or insulated to obtain coefficients as follows: Walls, 0.13; Wails 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 6). Floor (Bedroom D), 0.18. Solution: The procedure for calculating the heat losses is similar to that for Example 5. A summary of the results is given in Table 7. REFERENCES 1ACRMA Application Engineering Standards for Air Conditioning for Com fort, (1947), Air Conditioning and Refrigerating Machinery Association, Inc., pages 4 to 7. * An Analysis of Winter Temperatures for One Hundred and Twenty Cities, by Clark M. Humphreys (Carnegie Institute of Technology Bulletin 1939). J Investigation of Oil-Fired Forced Air Furnace Systems in the Research Resi dence, by A. P. Kratz and S. Konzo (University of Illinois Engineering Experiment Station Bulletin No. 318). t A.S.H.V.E. Research Report No. 1011--Tests of Three Heating Systems in an ,, Industrial Tyfc>e of Building, by G. L. Larson, D. W. Nelson, and John James (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 185). k 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, No. 17). A.S.H.V.E. Research Report No. 1213--Heat Loss Through Basement Walls mo by F. C. Houghten, S. I. Taimuty, Carl Gutberlet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 369). T Measurements of Heat Losses from Slab Floor, by R. S. Dill, W. C. Robinson and