Document xLr1K2e4k9q0jag04Gmmg0Qg

312 CHAPTER 13 1957'Guide * "Table 12 Transmittances and Absorptances of Common Window Glass for Direct and Diffuse Solar Radiation Angle of Incidence, 9, deg 0 20 40 50 60 70 80 90 Single Sheets TD aD TWO AIR-SPACED SHEETS aD aD ' tD Outdoor Sheet Indoor Sheet Fob Direct Radiation 0.87 0.87 0.86 0.84 0.79 0.67 0.42 0.0 0.79 0.05 0.05 0.06 0.06 0.06 0.06 0.06 0.0 0.76 0.76 0.74 0.72 0.66 0.52 0.25 0.0 0.06 0.06 0.06 0.07 0.07 0.07 0.07 0.0 Fob Diffuse or Set Solar Radiation 0.06 | 0.68 | 0.07 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 | 0.05 dry-bulb temperature cycle, with a 95 F maximum as tabulated. The total heat gain is the sum of the Table 13 and Table 14 values.' In preparing Table 14, convection and radiation heat exchange were combined, and a combined surface conductance of 4.0 used. Corrections to be applied for other design temperatures are given in Table 23 in a later section, Effect of Deviation from Design Conditions. Tables 13 and 14 may be used for other types of glass with good accuracy, by using the factors given in Table 15. Table 13 values are.multiplied by the appropriate factor given in Table 15 to obtain heat gain due to trans mitted solar radiation. For glasses having a transmittance for normally incident radiation differing from the table values, factors may be found by linear interpolation. To obtain instantaneous rates of heat gain by con vection and radiation, two steps are required. First, Table 14 values are multiplied by the appropriate coefficient of X listed in Table 15. Second, Table 16 values are multiplied by the appropriate coefficient of Y listed Fiq. 3. Convection and Radiation Heat Flow for Vertical Single Glas^ Cooling Load 313 .table m Lwo'iAW'iANEuus xvATEs of hbat Uain Due to Transmitted Dire and Diffuse or Sky Solar Radiation by a Single Sheet of Unshaded Common Window Glass For Clear Atmospheres and 18 Deg Declination, North (August 1) Note: For total instantaneous heat gain, add these values to the Table 14 values. Instantaneous Heat Gain in Btu per (hr) (sq pt) NE E 98 155 148 106 54 20 19 7 116 149 129 ` 79 31 18 17 - 54 128 139 107 54 18 16 16 108 190 205 180 128 59 19 6 131 195 205 180 127 58 19 .54 149 197 202 176 124 57 18 NW W SE 52 110 136 136 116 78 35 2 67 124 156 162 148 113 64 .20 81 136 171 183 174 143 96 SW SW 55 10 10 14 13 21 15 34 17 45 19 49 35 00 76 11 10 18 12 42 14 69 16 23 ' 64 3 7 12 10 32 12 72 14 110 16 136 42 144 96 SE W NW Hobiz. 5 5 17 10 10 71 13 13 137 15 15 195 16 16 241 18 18 267 19 19 276 0 0 -, 6 6 25 10 10 77 12 12 137 14 14 188 16 16 229 17 17 252 19 17 259 33 77 10 10 12 12 14 14 15 15 16 ' 16 18 16 6 34 80 129 173 206 227 234 E NE Horiz. -*1AWTAWE0US KATES OF HEAT GAIN BY CONVECTION AND Rj from a Single Sheet of Unshaded Common Window Glass For Clear Atmospheres and 18 Deg Declination, North (August 1) For 80 F Indoor Temperature Note: For total instantaneous heat gain, add these values to the Table IS values. Sun Tike Dry- North Bulb Latitude Deo F Degrees 5 &.m. 6 7 9 10 11 12 I p m* 3 4 5 6 7 8 9 74 --6 74 75 --6 77 --03 83 87 90 30,40,50 93 94 95 94 93 91 87 3 8 12 15 16 17 16 15 13 85 6 3 Instantaneous Heat Gain in Btu per (hr) (sq ft) NE --6 4 8 12 15 17 16 15 13 6 3 E --6 --4 --2 4 6 10 12 15 16 17 16 15 13 8 6 3 SE S --6 --6 --5 --6 --3 --6 0 --2 31 65 11 10 13 14 16 17 16 18 17 19 16 17 15 15 13 13 88 66 33 SW W --6 --0 --6 --6 --5 --5 -3 --3 00 33 98 13 12 17 17 19 19 21 21 20 20 18 19 14 15 88 66 33 NW --6 --6 --5 --3 0 8 12 15 17 19 18 15 8 8 3 Hob. --6 --5 --3 0. 3 16 20 21 13 8 3