Document Yvknx0EGvMNoByqZJpq70gVN

296 CHAPTER IS 1949 Guide> Table 15. Total Equivalent Temperature Differentials fob Calculating Heat Gain Through Sunlit and Shaded Walls Sun Time . North Latitude Wall Facing A.M. 8 10 12 34 P.M. 8( 10 12 South Latitude Wall Facing Exterior color of Wall--D - dark, L light NE E SE S SW w NW N (Shade) NE E ' SE S 8W W NW N (Shade) NE E SE S SW w NW N (Shade) NE E SE S SW w NW , N (Shade) L 1 DD D L D LD LDL D LD * D L Frame 22 10 24 12 14 10 12 10 14 14 14 14 10 10 6 4 2 2 30 14 36 1R 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 SE E NE N -4 --4 0 -2 -4 --4 0 0 >4 -4 0 --2 --4 -4 -2 --2 6 4 26 22 40 28 42 28 24 20 6 4 2 2 NW fi6 6 20 12 40 28 48 34 22 22 8 8 2 2 W 4 12 10 24 20 40 26 34 24 6 4 2 2 SW 4 , 4 10 10 14 14 12 12 8 8 4 4 0 0 - S (Shade) 4 In. Brick or Stonb Veneer + Fraua --2 -4 24 12 20 10 10 6 12 10 14 14 12 12 10 10 6 4 20 2 -2 30 20 14 1(1 31 28 17 14 14 12 12 14 14 12 12 1<J 16 26 16 18 14 14 14 12 12 10 8 8 6 6 6 6 -4 -4 --2 -2 . 12 6 24 16 -26 18 20 16 12 12 8 8 4 4 SE E NE 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 lfl 8 26 18 40 28 42 28 16 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 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 2 0 2 0 2 0 6 4 12 10 .28 18 30 20 26 18 8 6 4 2 4 2 4 2 6 4 10 8 18 14 30 22 32 22 lfl 14 0 0 (I 0 2 (1 -2 -2 --2 --2 -2 -2 4 0 2 0 8 6 6 12 1(1 22 18 30 22 10 6 10 10 10 10 10 10 6 fi 6 SE E NE N' NW W SW 8 (Shade) 8 In. Brick or.12 In. Hollow Txlb or 12 In. Cinder Block 22 8 .6 2 8 2 10 6 14 2 18 8 24 8 10 8 18 10 18 10 14 8 8 10 14 8 10 10 14 10 10 10 12 8 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 84 2 .2 6 6 2 46 46 2' 2 4 8 4 10 6 12 8 20 12 24 16 20 14 6 8 8 10 6 14 8 20 lfi 24 lfi 24 16 2 4 2 6 4 8 fi 10 8 lfi 14 18 14 0 0 0 0 0 0002268888866 > SE E NE N NW W SW 8 (Shade) 12 In. Brick ^ NE E SE S SW w NW N (Shade) NE E SE1 S SW -w NW ' N (Shade); . 868 12 8 12 10 6 10 868 10 6 10 12 8 12 868 442 68 8 12 6 10 66 6 10 8 12 68 22 48 8 10 6 10 46 4 10 4 12 6 12 6 10 6 10 6 12 a 14 n 14 10 14 fi 14 6 10 6 12 8 14 10 14 10 12 4 6 .4 8 4 10 6 12 8 12 6 fi fi 8 SE E NE N 6 10 8 10 48 22 6 10 6 1(1 48 22 6 10 <9 10 48 22 8 10 6 1(! 4 fi 22 8 12 6 12 e 10 24 8 14 10 fifi 16 10 10 fi . 466 NW W SW S (Shade) 8 In. Concrete or Stone or 6 In. or 8 In. Concrete Block 4240 6 4 14 8 fi 2 - 6 4 2121 '6 e 4 0` 2 4 2 0 42 6 4 4C 00 16 8 14 8 10 6 12 8 12 10 10 8 fl '6 24 12 24 12 lfi 1(! 14 lfi 14 10 12 1(1 10 .fi li 1C 18 12 It 12 14 12 12 10 12 id 10 4 . 1 12 6 16 12 18 12 14 12 10 8 8 . 6 6 2 8 4 14 10 22 16 24 16 22 16 10 8 fi fi fi6 4 fi C 12 fi 20 14 2fi lfi 26 lfi 14 10 4 244 12 K 2fi 14 22 16 0 0224466886644 SE E NE N NW W SW S (Shade) CooUngLad 297 Table 15--Concluded. Total Equivalent Temperatube Differentials fob Calculating Heat Gain Through Sunlit and Shaded Walls Sun Time North Latitude Wau. Facing E SE S W NW N(Shade) A.M. P.M. 88 to 12 2 4 6 10 12 Exterior color of Wall--D = dark, t light D D L D L D DLDLD 12 In. Concrete or Stone DLDL 6 4 6 2 6 2 14 8 14 8 10 8 10 8 12 10 10 8 10 6 8 6 10 6 18 10 18 12 16 10 12 10 14 10 14 10 fi 4 8 4 6 4 14 8 16 10 16 10 14 10 12 10 12 10 6 4 4 2 4 2 4 2 10 6 14 10 16 12 14 10 JO 8 8 4 8 4 6 4 6 4 8 6 10 8 18 14 20 14 18 12 fi10 6 8 0 8 6 10 6 10 6 12 16 10 24 14 22 14 fi 4 6 2 6 2 6 4 6 4 8 6 10 8 lfi 12 20 14 0 0 0 0 0 0002 24 466 886 6 South Latitude Wall Faczno '' SE E NE N NW W SW S (Shade) NOTES FOR TABLE 15 Explanation: Total heat transmission from solar 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 wall Btu per (hr) (sq ft) (F deg) NOTES: '- - i. ,50 URCE. Same as Table 14. A north wall has been assumed to be a wall in the shade; this is practically true. Dark colors on exterior surface of walls have been assumed to absorb 90 per cent of solar radiation and reflect 10 per cent; white colors absorb 50 per cent and reflect 50 per cent. This includes some allowance' for dust and dirt since clean, fresh' white paint normally absorbs only 40 per cent 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 95 F, in which 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, oorrect 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 3 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 cor 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 fight' 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, greeny etc., are considered dark colors. For latitudes other than 10 deg north; and tn 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 60 deg to 00 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 (tx) for any wall facing, and for any latitude for any. month may be approximated as follows: i. = i. + jjx (i.-w where tm = temperature differential for the same wall in shade for desired time of day; obtained from Table 15. L = 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 /i except use the maximum value for wall facing, for month, and latitude desired for <x- temperature differential for particular wall facing','for the desired time of day from above table. (Nets that this makes adjustment only for solar radiation.and-that there may be additional 'correction for outdoor temperature.) i FOR IN^UfifiTBp WALLS use same temperature differentials as used for uninsulated watts." .'f