Document qmQ4YRb9r24BbQjr9dYQ1eXdx

286 CHAPTER 13 Table 10. Total Equivalent1 Temperature Differentials fob Calculating!;. Heat Gain Through Sunlit and Shaded Walls North . . Latitude Watj. Facing NE E SE S sw w NW N (Shade) NE E . SE S SW w NW N (Shade) NE E SE S SW W NW N (Shade) ' NE E SE S SW w NW.. N (Shade) NE E SE S SW W NW N (Shade) NE E SE S SW w NW N (Shade) .8 Sun Time A.M. 10 12 Exterior color of Wal --L P.M. - 6 10 dark, L -- light 12 .:3T*i* South Latitubb Watj. Facing -'*1 D LD D D LD LD D LD DL Frame 22 10 24 12 14 10 12 10 14 14 14 14 10 10 6 4 2 2 30 14 36 18 32 16 12 12 14 14 14 14 10 10 6 6 2 2 13 6 26 16 28 18 24 16 16 14 14 14 10 10 6 4 2 2 -4 -4 4 0 22 12 30 20 26 20 16 14 10 10 6 6 2 2 -4' -4 0 -2 6 4 26 22 40 28 42 28 24 20 6 4 2 2 -4 -4 0 0 6 6 20 12 40 28 48 34 22 22 8 8 2 2 -4 -4 0 -2 6 4 12 10 24 20 40 26 34 24 6 4 2 2 -4 -4 -2 -2 4 4 10 10 14 14 12 12 8 8 4 4 0 0 SE E NE N 7 NW w sw S (Shade) 4 In. Brick OR Stone Veneer + Frame -2 -4 24 12 20 10 10 6 12 10 14 14 12 12 10 10 6 4 . 2 0 30 14 31 17 14 14 12 12 14 14 12 12 10 8 6 6 2 -2 20 10 28 16 28 16 18 14 14 14 12 12 10 8 6 6 -4 -4 -2 -2. 12 6 24 16 26 18 20 16 12 12 8 8 4 4 0 -2 0 -2 2 2 12 8 32 22 36 26 34 24 10 8 6 6 0 -2 0 0 4 2 10 8 26 18 40 28 42 28 16 14 6 6 -4 -4 -2 -2 2 2 8 6 12 12 30 22 34 24 12 10 6 6 -4 -4 -2 -2 0 0 6 6 10 10 12 12 12 12 8 8 4 4 SE E NE N NW W SW S (Shade) . 8 In. Hollow Tile OR 8 In. Cinder Block 0 0 0 0 20 10 16 10 10 6 12 10 14 12 12 10 8 8 4 2 12 4 24 12 26 14 20 12 12 10 14 12 14 10 10 8 2 0 2 0 16 8 20 12 20 14 14 12 14 12 12 10 8 6 0 0 0 0 2 0 12 6 24 14 26 16 20 14 12 10 8 6 20 2 0 2 0 42 4242 000020 -2 -2 -2 -2 -2 -2 6 4 12 10 26 18 30 20 26 18 8 6 6 4 10 8 18 14 30 22 32 22 18 14 4 2 8 6 12 10 22 18 30 22 10 8 0 0 6 6 10 10 10 10 10 10 6 6 8 In. Brick or 12 In. Hollow Tile or 12 In. Cinder Block 2 2 2 2 10 2 16 8 14 8 10 6 10 8 10 10 10 8 8 6 8 6 14 8 18 10 18 10 14 8 14 10 14 10 12 10 8 4 6 4 6 4 14 10 18 12 16 12 12 10 12 10 12 10 4 2 4 2 4 2 4 2 10 6 16 10 16 12 12 10 10 8 8 4 6 4 6 4 8 4 10 6 12 8 20 12 24 16 20 14 8 4 6 4 6 6 8 6 10 6 14 8 20 26 24 16 24 16 2 2 2 2 2 2 4 2 6 4 8 6 10 8 16 14 18 14 0 0 0 0 0 0 00 2 2 6 6 88 8 866 12 In. Brick 8 6 8 6 8 4 8 4 10 4 12 6 12 6 10 6 10 6 12 8 12 8 12 8 10 6 12 8 14 10 14 10 14 8 14 8 10 6 10 6 10 6 10 6 10 6 12 8 14 10 14 10 12 8 8 6 8 6 6 4 6 4 6 4 8 4 10 6 12 8 12 8 10 6 10 6 10 6 10 6< 10 6 10 8 10 8 12 8 14 10 12 8 12 8 12 8 10 6 10 6 10 6 10 6 12 8 16 10 8 6 8 6 8 4 8 4 8 4 8 4 8 6 10 6 10 6 4 4 2 2 2 2 2 2 2 2 2 2i 2 2 4 4 6 6 8 In. Concrete or Stone OR 6 In. or 8 In. Concrete Block 4 2 4 0 16 8 14 8 10 6 12 8 12 10 10 8 8 6 6 4 14 8 24 12 24 12 18 10 14 10 14 10 12 10 10 8 6 2 6 4 16 10 18 12 18 12 14 12 12 10 12 10 10 8 2 1 2 1 4 1 12 6 16 12 Ifl 12 14 12 10 8 8 6 6 2 4 2 6 2 8 4 14 10 22 16 24 16 22 16 10 8 6 4 6 4 6 4 8 6 12 8 2C 14 28 18 26 18 U 10 4 2 4 0 4 2 4 4 6 6 12 10 20 14 22 16 i 6 0 0 0 0 0 0 22 4 4( 68 86644 SE E NE N NW w SW S (Shade) SE E NE N NW w SW S (Shade) .: . -J SE E NE N __ NW W SW S (Shade) SE ` E N NE __ _ NW W sw , * S (Shade) _____ _ Cooling Load 287 10.Table Total Equivalent Temperature Differentials for Calculating Heat Gain Through Sunlit and Shaded Walls--Concluded. Sun Time North Latitude Facing NE E SE S SW W NW N (Shade) A.M. I 10 12 2 P.M. 8 10 12 South Wall Exterior color of Wall--D =* dark, L = light D L D L D L D DLD DLDLDL 12 In. Concrete or Stone 6 4 6 2 6 2 14 8 .14 8 10 8 10 8 12 10 10 8 SE 10 6 8 6 10 6 18 10 18 12 16 10 12 10 14 10 14 10 E 6 4 8 4 6. 4 14 8 16 10 16 10 14 10 12 10 12 10 NE 6 4 4 2 4 2 4 2 10 6 14 10 16 12 14 10 10 8 N 8 4 8 4 6 4 6 4 8 6 10 8 18 14 20 14 18 12 NW 10 6 8 6 8 6 10 6 10 6 12 8 16 10 24 14 22 14 W 6 4 6 2 6 2 6 4 6 4 8 6 10 8 18 12 20 14 SW 0 0 0 0 0 0 0 0 2 2 4 4 6 6 8 8 6 6 . S (Shade) NOTES FOR TABLE 10 Explanation: Total heat transmission from solar radiation and temperature difference between outside and room air, Btu per (hr} (sq ft wall area) Equivalent temperature Heat transmission differential from above table X coefficient for wall, Btu per (hr) (sq ft). (F deg) NOTES: 1. SOURCE. Same as Table 9. A north wall has been assumed to be a wall in theshade; thisis practi cally true. Dark colors on exterior surface of walls have been assumed to absorb 90 percent of solar radiation and reflect 10 percent; white colors absorb 60 percent and reflect 50 percent. This includes some allowance for dust and dirt since clean, fresh white paint normally absorbs only 40 percent of solar radiation. 2. APPLICATION. These values may be used for all normal air conditioning estimates, usually with out corrections, when the load is calculated for the hottest weather. Correction for latitude (Note 3) is neces sary only where extreme accuracy is required. There may be jobs where the indoor room temperature ia considerably above or below 80 F, or where the outdoor design temperature is considerably above 96 F, in whjch case it may be desirable to make correction to the temperature differentials shown. The solar intensity on all walls other than east and west varies considerably with time of year. . 3. CORRECTIONS. Outdoor minus room temperature. If the outdoor maximum design temperature minus room temperature is different from the base of 15 deg, correct as follows: When the difference is greater (or less) than 15 deg, add the excess to (or subtract the deficiency from) the above differentials. Outdoor daily range temperature. If the daily range of temperature is less than 20 deg, add 1 deg to every t deg lower daily range; if the daily range is greater than 20 deg, subtract 1 deg for every .2 deg higher daily ran9e* .For example, the daily range in Miami, Florida is 12 deg, or 8 deg less than 20 deg; therefore, the cor rection is +4 deg. of exterior surface of ttall. Use temperature differentials for light walls only where the permanence i the light wall is established by experience. For cream colors use the values for light walls. For medium colors interpolate half way between the dark and light values. Medium colors are medium blue, medium green, bright red, light brown, unpainted wood, natural color concrete, etc. Dark blue, red, brown, green, tc., are considered dark colors. t Fr Jo tiludes other than 40 deg north; and in other months. These table values will be approximately correct j r th *st or west wall in any latitude (0 deg to 50 deg North or South) during the hottest weather. In the -Vft,tudes when the maximum solar altitude is approximately 80 deg to 90 deg (the maximum occurs at orAh 6 ^"P^ature differential for either a south or north wall will be approximately the same as a north, snade wall. The temperature differential (lx) for any wall facing, and for any latitude for any month may 06 approximated as follows: (x = tg + j- X (tw fg) tohere = temperature differential for the same wall in shade for desired time of day; obtained from Table 10. fj -- maximum solar radiation intensity transmitted through glass, Btu per (hr) (sq ft) for particular wall facing, in July, 40 deg north latitude (note: this is maximum value irrespective of time). -- same as h except use the maximum value for wall facing, for month, and latitude desired for ti. iw ~ temperature differential for particular wall facing, for the desired time of day from above table. (Note that this makes adjustment only for solar radiation, and that there may be additional correction for outdoor temperature.) FOR INSULATED WALLS use same temperature differentials as used for uninsulated walls.