Document jm97e91g7ndEXDdBy8EZa8775

260 CHAPTER 12 1953 `Guide Notes fob Table 7. ` The inside-outside temperature difference is 70- (-10) or SO F except where otherwise noted. Volume of infiltration, cfh = (no. air changes) x (door or ceiling area) x (ceiling height). .e From Equation 5a; d ceilinghe&t losses are calculated by estimating the attic temperature and then calculating the loss tnrougb 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- "T10 f "d room temperature is 70 F. The temperature difference is then 70--30.2 or 39.8 deg. Y or the insulated residence, attic temperature becomes 4.6 F and temperature difference 70--4.6 65.4 deg. * Temperature in garage assumed to be 35 F. (U =^0?39)en^ *r W&^ ad^ garae calculated on basis of metal lath and plaster on both sides of studs * One half of value from Table 4, Chapter 11, for Storm windows or weatherstripping. ^ Exposed on two sides, weatherstripped windows offset by fire-place. Use \Yi. 1 Window on one side weatherstripped but double-doors are hard to close tightly. Hence conservative value of 1H- ... ' * Assuming kitchen vent, door to vestibule usually open, allow full table value of \Yi. * One-half value in Table 4, Chapter 11, increased to 1H by nearby outside door in vestibule. 1 Full value in Table 4, Chapter 11, to allow for frequent opening of outside door. . " Two sides exposed, large doors but large volume. Use value 1# as given in Table 4, Chapter 11. "Two small unweatherstripped windows in protected location, but fireplace, indicate 1 change. p Heat losses from these rooms into garage are heat gains for garage. 9 Neglect heat loss to basement, as losses from boiler, piping, etc., will probably keep basement near if not above, 70 F. .. ' T Upstairs ball ceiling figures with downstairs. Heat should be provided downstairs for both. 8 Linear feet of exposed edge. Table 8. Summary of Heat Losses of Uninsulated Residence (Btu Per Hour) Room or Space Walls Ceiling and Roof Floor Glass and Door Infil tration Totals Bedroom A Bedroom B Bedroom C Bedroom D Bathroom 1 Bathroom 2 Lving Room Dining Room Kitchen Lavette Entrance Hall Garage Recreation Design Totals Operating Totals8 Percentages*1 5330 3490 2560 2650 670 1640 7260 3720 2850 3000 870 --1030* 840 33,850 33.850 38.4 6910 4660 3540 3020 1510 960 2390. --1270" 21,720 21,720 24.6 960 3io 1060 570 2,900 2,900 3.3 1440 1440 970 720 500 320 1800 3100 950 1100 640 3710 720 - 17,410 17,410 19.7 2180 1470 1260 950 630 400 5400 3080 2300 550 1600 1910 2890 24,620 12,310 14.0 15,860 11,060 14.460 9,900 6,100 4.650 4,380 5,020 100,500 88.190 100.0 8 Wall heat loss of 2110 Btuh minus wall heat gains of 1280, 700 and 1160 Btuh.' b Heat gains of 960 and 310 Btuh. e Based on Yi computed infiltration. " Based on operating totals. ' Table 9. Summary of Heat Losses of Insulated Residence (Btu Per Hour) Room or 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 Totals8 Percentages*1 Walter 2480 1620 1190 1230 310 760 3370 1730 1320 1390 410 --470* 840 16,180 16.180 29.1 Ceiling and Roof 2460 1660 1260 1080 540 250 850. --910*> . 7,190 7,190 12.9 Floor . 690 220 1060 570 2,540 2,540 4.6 Glass and Door ---------------- 0~ 1440 1440 970 720 500 320 1800 3100 950 1100 640 3710 700 Infil tration 2180 1470 1260 950 630 .400 5400 3080 2300 550 1600 1910 .2890 17,410 17,410 31.3 24,620 12.310 22.1 Totals 8,560 6.190 4,680 4,670 1,980 1,950 10,570 7.910 4,570 3,040 3,500 5.300 5,020 67,940 55,630 100.0 8 Wall heat loss of 980 Btuh minus wall heat gains of 590, 320 and 540 Btuh. b Heat gains 690 and 220 Btuh. e Based on Yt computed infiltration. ^ Based on operating totals. Heating Load 261 actual heating installation (exclusive of heat sources) be reduced below that required to maintain at least 40 F in the building. Electric Motors and Machinery Motors and the machinery which they drive, if both are located in the room, convert all of the electrical energy supplied into heat. This heat is retained in'the room if the product manufactured is not removed until its temperature is the same as the room temperature. If power is transmitted to the machinery from the outside, then only the heat equivalent of the brake horsepower supplied is used. In some mills this is the chief source of heating, and it is frequently sufficient to overheat the building even in zero weather, thus requiring cooling by ventilation the year 'round. Table 6 shows the heat output equivalent of various sources, of heat ip a factory. For information concerning the heat supplied by persons, refer to data given in Chapter 6, and also Table 25, Chapter 13. For appliances see Table 26, Chapter 13. INTERMITTENTLY HEATED BUILDINGS In the case of intermittently heated buildings additional heat is required for raising the temperature of the air, the building materials and the ma terial contents of the building to the specified inside temperature. The rate at which this additional heat must be supplied depends upon the heat capacity of the structure and its material contents, and upon the time in which these are to be heated.15 . This additional heat may be computed and allowed for as conditions re-' quire, but inasmuch as the heating system proportioned for taking care of the heat losses will visually have a capacity about 100 percent greater than that required for average winter weather, and inasmuch as most buildings 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 size of boilers or furnaces. For churches, auditoriums and other intermittently heated buildings, additional capacity should be provided. RESIDENCE HEAT LOSS PROBLEMS Example 6: Calculate the heat loss of the residence shown in Fig 3 located in the vicinity of Chicago. From Table 1, design outdoor conditions are --10 F and 12mph 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 35) under basement and garage floors and 32 F adjoining basement walls. Estimate infiltration losseB 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 plaster (0.28). Walls of dormer over garage, Bame 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 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