Document Q7ZyJaDEeDZYMKvYRmVD4ELk

282 CHAPTER 12 1952 Guide Table 13. Total Equivalent Temperatube Differentials for Calculating Heat Gain Through Sunlit and Shaded Walls Sun Time * Nobth . Latitude . Wall - Facing .8 A.M. 10 12 2 ` Exterior oolor of Wal --E P.M. 6 6 10 dark, L =* light 12 South -Latitude Wall Facing DLD D D LD LD D D D Frame NE E SE 8 sw W NW N (Shade) 22 10 24 12 14 10 12 10 14 14 14 14 10 10 6 4 2 2 ' SE 30 14 3d 18 32 16 12 12 14 14 14 14 10 10 6 6 2 .2 E 13 6 28 16 28 18 24 16 16 14 14 14 10 10 6 4 2 2 NE -4 -4 4 0 22 12 30 20 26 20 16 14 10 10 6 6 2 2 N -4 -4 0 -2 6 4 26 22 40 28 42 28 24 20 6 4 2 2 NW -4 -4 0 0 6 6 20 12 40 28 48 34 22 22 8 8 2 2 W -4 -4 0 -2 6 4 12 10 24 20 40 26 34 24 6 4 2 2 SW --4 -4 -2 -2 4 4 10 10 14 14 12 12 8 8 4 4 0 0 . 8 (Shade) 4 In . Brick OB Stone Veneer + Frame NE E SE S sw w NW N (Shade) -2 -4 24 12 20 10 10 6 12 10 14 14 12 12 10 10 6 4 - SE' 2 0 30 14 31 17 14 14 12 12 14 14 12 12 10 8 6 6 E 2 -2 20 10 28 16 26 16 18 14 14 14 12 12 10 8 6 6 NE -4 -4 -2 -2 12 6 24 16 26 18 20 16 12 12 8 8 4 4 N 0 -2 0 -2 2 2 12 8 32 22 36 26 34 24 10 8 6 6 NW 0 -2 0 0 4 2 10 8 26 18 40 28 42 28 18 14 6 6 W -4 -4 -2 -2 2 2 8 6 12 12 30 22 34 24 12 10 6 6 SW -4 -4 -2 -2 0 0 6 6 10 10 12 12 12 12 8 8 4 4 8 (Shade) 8 In. Hollow Tile on 8 In. Cindeb Block NE E SE 8 SW- w NW . N (Shade) 0 0 0 0 20 10 16 10 10 6 12 10 14 12 12 10 8 8 SE 4 2 12 4 24 12 26 14 20 12 .12 10 14 12 14 10 10 8 E 2 0 2 0 16 8 20 12 20 14 14 12 14 12 12 10 8 6 NE 0 0 0 0 . 2 0 12 6 .24 14 26 16 20 14 12 10 8 6 . N 202020 4242 42 000020 -2 -2 -2 -2 -2 -2 6 4 12 10 26 18 30 20 26 18 8 6 NW 6 4 10 8 18 14 30 22 32 22 16 14 W 4 2 8 6 12 10 22 18 30 22 10 8 - SW 0 0 6 6 10 10 10 10 10 10 6 6 S (Shade) 8 In. Brick or 12 In. Hollow Tile or 12 In. Cinder Block NE E SE S SW w NW N (Shade) 2 2 2 2 10 2 16 8 14 8 10 6 10 8 10 10 10 8 SE 8 6 8 6 14 8 18 10 18 10 14 8 14 10 14 10 12 10 E .. . 8 4 6 4 6 4 14 10 18 12 16 12 12 10 12 10 12 10 NE 4 2 4 2 4 2 4 2 10 6 16 10 16 12 12 10 10 8 N 8 4 6 4 6 4 8 4 10 6 12 8 20 12 24 16 20 14 NW ' 8 4 6 4 6 6 8 6 10 6 14 8 20 16 24 16 24 16 W 2 2 2 2 2 2 4 2 6 4 8 6 10 8 16 14 18 14 SW 60 0 0 0 0 0 0 0 2 . 6 8 8 8 8 6 6 S (Shade) . 12 In. Brick NE E SE S sw w NW N (Shade) fl8 6 8 6 8 4 8 4 10 4 12 6 12 6 10 6 10 6 SE 12 8 12 8 12 8 10 6 12 8 14 10 14 10 14 14 8 E 10 6 10 6 10 6 10 6 10 6 12 8 14 10 14 10 12 8 NE 8 6 8 6 6 4 6 4 6 4 8 4 10 6 12 8 12 8 N 10 6 10 6 10 6 10 6 10 6 10 8 10 8 12 8 14 10 NW 12 8 12 8 12 8 10 6 10 6 10 6 10 6 12 8 16 10 W 8 6 8 6 8 4 8 4 8 4 8 4 8 6 10 6 10 6 SW 4 4 2 2 2 2 2 2 2 2 ' 2 2 2 2 4 4 6 6 S (Shade) 8 In. Concrete or Stone OR 6 In. or 8 In. Concrete Block NE E SE S SW ' w NW N (Shade) 4 2 4 0 16 8 14 8 10 6 12 8 12 10 10 8 8 6 SE 6 4 14 8 24 12 24 12 18 10 14 10 14 10 12 10 10 a E 6 2 6 4 16 10 18 12 18 12 14 12 12 10 12 10 10 8 NE 2 1 2 1 4 1 12 6 16 12 18 12 14 12 10 8 8 6 N 6 2 4 2 6 2 8 4 14 10 22 16 24 16 22 16 10 8 NW 64 6 4 648 12 8 -2C lA 28 18 2f 18 14 10 W 4 0 2 0 4 0. 0 0 4 0 2 0 A A e ( 11 1C 2C 1A 22 16 f 6 .SW 2 2 4 4 6 6 8 8 6 6 4 4 S (Shade) Cooling Load 283 Table 13. Total Equivalent Temperature Differentials fob Calculating Heat Gain Through Sunlit and Shaded Walls--Concluded. Sun Time North Wall . NE E SE S SW W NW N (Shade) A.M. P.M. 8 10 12 i - l 1 10 12 Exterior color of Wail --D -- dark, L = light D LDL D DL D LDL DLD 12 In. Concrete or Stone L 6 .4 10 6 84 6 4' 84 10 6 64 00 6 8 8 4 8 8 6 0 26 6 10 46 24 46 68 26 00 2 14 8 14 8 10 8 10 8 12 10 10 8 6 18 10 18 12 16 10 12 10 14 10 14 10 4 14 8 16 10 16 10 14 10 12 10 12 10 2 4 2 10 6 14 10 16 12 J4 10 10 8 4 6 4 8 6 10 8 18 14 20 14 18 12 6 10 6 10 6 12 8 16 10 24 14 22 14 2 6 4 6 4 8 6 10 8 18 12 20 14 0 002244668866 South Wall Facing SE E NE N NW W SW S (Shade) NOTES FOR TABLE 13 total heat transmission from solar Explanation: radiation and temperature difference between outside and room air, Btu per (hr) (sq ft wall area) Equivalent temperature differential from above table Heat transmission coefficient for wail, Btu per (hr) (sq ft) (F deg) NOTES: 1. SOURCE. Same as Table 12: A north wall has been assumed to be a wall in the shade; this is 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 50 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 is. considerably above or below 80 F, or where the outdoor design temperature is considerably above 85 F. ih which case it may be desirable to make correction to the temperature differentials shown. Thesolar intensity on all walls other than east and west varies consi derably 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 2 deg lower daily range; if the daily range is greater than 20 deg, subtract 1 deg for every 2 deg higher daily range. For example, the daily range in Miami, Florida is 12 deg, or 8 deg less than 20 deg; therefore, the dor-.. rection is +4 deg. Color of exterior surface of wall. Use temperature differentials for light walls only where the permanence of the light wall is established by experience. For cream colors use the values for light walls. For medium colors interpolate h1f 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, etc., are considered dark colors. Forlalitudes other than 40 deg north; and in other months. These table values will be approximately correct for the east or west wall in any latitude (0 deg to 50 deg North or South) during the hottest weather. In the lower latitudes when the maximum solar altitude is approximately 80 deg to 90 deg (the maximum occurs at noon) the temperature differential for either a south or north wall will be approximately the same as a north,, or shade wall. The temperature differential (lx) for any wall facing, and for any latitude for any month may be approximated as follows: lx <.+x .-(.) where < = temperature differential for the same wall in shade for desired time of day; obtained from Table 13. h -- 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). It = same as Ii except use the maximum value for wall facing, for month, and latitude desired for lx.. tw = temperature differential for particular wall facing, for the desired time of day from above table. (Note that this makes adjustment only /or solar radiation, and that there may be additional correction for outdoor temperature.) 4. FOR INSULATED W ALLS use same temperature differentials as used for uninsulated walla.