Document ykaXQKe4bjq89MvjV9DYZbwn3

:254 CEUPTER 11 1952 Guide Notes Fon Table 6., The insidfreuleide temperature difference is 70- (-10) or 80 F racept where otherwise noted. b Volume of infiltration, cfh = (no. air changes) x (floor or ceiling area) x (ceiling height). ... e From Equation.Sa. .. . ....... d The ceiling beat losses are calculated by estimating the attic temperature and then calculating the loss through theceiling using the proper temperature difference. This unheated attic is not ventilated during winter months] The attic temperature is estimated from Equation lto be 30.2'F when the outside^tem perature ia--10-F and room temperature is 70 F. The temperature difference is then 70--30.2 or-39.8 deg. For.the residence, attio temperature becomes 4.6 F and temperature difference 70--4.6 = 65.4 deg. '~"m Temperature in garagd assumed to be 35 F. . t Coefficient for wall adjoining garage calculated on basis of metal lath and plaster on both sides of studs (V - 0.39). .................................................................... t One half of value from Table 4, Chapter 10, for storm windows or weatberetripping. b Exposed on two sides, weatherstripped. windows offset by fire-place. Use 1)4* I Window on one side weatherstripped but double-doors are hard to dose tightly. . Hence, conservative value of 1V$. ........................ ......... i Ammmltig kitchen vent, doot to vestibule usually open, allow full table value of k One-half value in Table 4, Chapter 10, increased to IH by nearby outside door in vestibule. 1 Full value in Table 4, Chapter 10, to allow for frequent opening of outside door. - - " Two sides exposed, large doors but large volume. Use value IJ4 as given in Table 4, Chapter 10. B Two tw11 unweaiherstripped windows in protected location, but fireplace, indicate 1 change; P Heat losses from these rooms into garage are heat gains for garage. 4 Neglect beat loss to basement, as losses from boiler, piping, etc., will probably keep basement near, f not above, 70 F. ; Upstairs hall cealing figured with downstairs. Heat should be provided downstairs for both;. * Linear feet of exposed edge. Table 7. Sdmmary of Heat Losses of Uninsulated Residence (fitu Per Hour) Room ob Space Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 . Living Room Dining Room Kitchen Lavette Entrance Hall Garage Recreation Design Totals Operating Totals6 Percentages" - Walls 6330 3490 2560 2660 670 1640 7260 3720 2850 3000 870 --1030* 840 33,850 33,850 38.4 Csana and Root 6910 4660 3540 . 3020. 1510 960 . 2390. --1270b. 21,720 21,720. 24.6- Floob Glass and Doob 1440 1440 970 .960 720 sio 500 320 .. . 1800 3100 950 1100 640 1060 .3710 570 - . 720 2,900 2,900 3.3 17,410 17,410 19.7 InfilTBATION Totals 2180 1470 1260 950 630 400 5400 3080 2300 550 1600 1910 2890 15,860 11,060 8,330 8.300 3,310 3,630 .- . 14.460. . 9.900 6,100 4.650 5,500 4,380 ,. 5.020 24,620 12,310 14.0 100,500 88,190 100.0 * Wall heat loss of 2110 Btuh minus-wall heat gains of 1280,700 and 1160-Btuh. b Heat gains of 960 and 810 Btuh. 0 Based on H computed infiltration. Based on operating totals. Table 8. Summaby of Heat Losses of Insulated Residence (Ptu Per Hour) Room ob Space Bedroom A Bedroom B .Bedroom C Bedroom D Bathroom 1 'Bathroom 2 Living Room Dtning Room Kitchen lavette Entrance Hall Garage Recreation Design Totals. Operating Totals Percentages* . Walls Csxuno . and Roof' 2480 1620 1190 1230 310 760 3370 1730 1320 1390 410 ' -470* 840 2460 1660 1260 1080 540 0 850. -OlO1* 16,180 16.180 29.1 7,190 7,190 12.9 Floob - 690 220 1060 570 2,540 2,540 4.6 Glass and Doob 1440 1440 . 970 ' ` 720 500 320 1800 8100 950 1100 640 3710 720 17,410 17,410 31.3 Infil tration 2180 1470 1260 950 630 400 5400 3080 2300 550 1600 1910 2890 24,620 12.310 22.1 Totals 8,560 6.190 4,680 4.670 . l,98fr* 1,950 10,570 7,910 4,570 3,040 3.500 5.300 5.020 67.940 55.630 100.0 Wall heat loes of 680 Btuh minus wall heat gains of 590,320 and 540 Btuh. b Heat gains 690 and 220 Btuh. c Based on Vi computed infiltration. d Based on operating totals. Heating Load 255 biiildings may either be continuously heated, or have more time allowed for heating up during the few minimum temperature days, no allowance usually is made, except in the site of boilers or furnaces. For/chrirches, auditoriuriis and other intenriittently heated buildings, additional capacity should be provided. RESIDENCE HEAT LOSS PROBLEMS Example 6: Calculate the heat Iosb of the residence shown in Fig. 3 located in the vicinity of Chicago. From Table 1, design outdoor conditions are --10 F and 12 mph 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 parentheses): Walls: Brick veneer, building paper, wood sheathing, studding, metal lath and Elaster (0.28). Walls of dormer over garage,-same except wood siding in place of rick 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 rafters (0.53). Ceiling (Second floor): Metal lath and plaster (0.69). Windows: Double-hung wood windows averaging 70 percent glass (0.45; from Chapter 9, Table 19, Section D, the U value for wood windows with,storm sash is 0.53 x application factor; by interpolation this factor is 0.85). Steel casement sash in garage and basement (1.13; from Chapter 9, Table 19, U is 1.13 for all glass and the application, factor is 1.00). French doors in dining room 50 percent glass, no storm doors (0.85; from Chapter'9, Table: 19, U is 1.13 for all glass; by interpolation the application factor is 0.75). Floor (Bedroom D): Maple finish flooring on yellow pine sub-flooririg; metal lath and plaster ceiling below (0.25). Floor (Basement and Garage): 4 in. stone concrete on,3 in. cinder concrete (0.10). Solution: The calculations for this problem are given in Table 6, and a summary of the results in Table 7. The values in column'F of Table 6 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 6 for further explanation of data. Attention is called to the summary of heat losses (Table 7) for the uninsulated resi dence. As storm windows are used in this instance the glass and door transmission heat losses of 19.8 percent are relatively small. The infiltration losses of 14.0 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 66.2 percent of the total. Example 7: Calculate the heat loss of residence shown in Fig. 3 based on the same conditions as in Example 6 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 6). 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 8. REFERENCES 1 ACRMA Application Engineering Standards for Air Conditioning for Com fort, (1947), Air Conditioning and Refrigerating Machinery Association, Inc., pages 4 to 7.