Document zoENJnpw1LGqMbkxNOrZwo5xm

HEATING VENTILATING AIR CONDITIONING CUIDE 1944 Table 1. Design Dry- and Wet-Bulb Temperatures, Wind Velocities, and Wind Directions for June, July, August, and September (Concluded) State Crrr Design Drt-Bulb Design Wet-Bulb Summer Wind Velocitt MPH Prevailing Suuheb Wind .Direction Texas:........... Dallas................. ,,............ ....... 100 78 9.4 S El Paso._ ................................ 100 69 6.9 E Galveston.... ............................ 95 80 9.7 S Houston_________ ____ :......... 95 78 7.7 S San Antonio............................ 100 78 7.4 SE Utah.............. Salt Lake City.________ ;___ 92 63 8.2 SE Vt. 90 73 8.9 S Va. 95 78 10.9 S Richmond................................ 95 78 6.2 sw Wash.........:... Seattle___________ 1_____ ____ 85 65 7.9 s Spokane.................................... 90 65 6.5 sw W Va. 95 75 5.3 SE Wis, : 95 75 8.1 SW Milwaukee.. -.......:................. 95 75 10.4 S Wyp..... ......... Cheyenne. .......... ...... . 95 65 9.2 s The components of heat gain, classified by source, are further classified as sensible and latent heat gain. The first two components fall into the classification of sensible heat gain, that is, they tend to raise the temperature of the air within the structure. The last three components not only produce sensible heat gain but they may also tend to increase the moisture content of the air within the structure. Normal Heat Transmission By normal heat transmission, as distinguished from solar heat trans mission, is meant the transmission of heat through windows, walls, partitions, etc. from without to interior of enclosure 6y virtue of difference between outside and inside air temperatures. This load is calculated in a manner similar to that described in Chapter 6 (except that flow of heat is reversed) by means of the formula: Hi = AU {to -- t) (1) where Hi = heat transmitted through the material of wall, glass, floor, etc., Btu per hour. A = net inside area of wall, glass, floor, etc., square feet. I .= inside temperature, degrees Fahrenheit. to = outside temperature, degrees Fahrenheit. U = coefficient of transmission of wall, glass, floor, etc., Btu per hour per square foot per degree Fahrenheit difference in temperature (Tables 3 to 13, Chapter 4). Solar Heat Transmission Calculations of the solar heat transmitted - through walls and roofs are difficult to determine because of periodic character of heat flow and time lag-due to heat capacity of construction; .148 CHAPTER 7. COOLING LOAD Table 2. Solar Radiation (Direct plus Sky) Impinging Against Walls Having Several Orientations and a Horizontal Surface For SO'Deg North Latitude on August 1 Tims Northeast intensity of Solar Radiation, Btu per Sq Ft per Hour East Southeast South Southwest West Northwest Horizontal Surface 5:20 6:00. 7:00 8:00 9:00 10:00 11:00 12:00 1:00 2:00 3:00 4:00 5:00 6:00 6:40 0 37 119 153 130 86 35 26 25.5 23.5 21 17 11 4.5 0 0 47 145 207 194 152 ' 94 26 25.5 23.5 21 17 11 4.5 0 0 23 91 149 158 143 85 65 25.5 , 23.5 21 17 11 4.5 0 0 4.5 11 17 35 63 80 85 80 63 35 17 11 4.5 0 0 4.5 11 17 21 23.5 25.5 65 85 143 158 149 91 23 0 0 4.5 11 0 4.5 11 17 21 23.5 17 21 23.5 25.5 26 94 . 25.5 26 35 152 86 194 130 207 153 145 . 119 47 37 00 0 n 64 147 213 262 290 300 290 262 . 213 147 64 11 0 Table 3. Solar Radiation (Direct plus Sky) Impinging Against Walls Having Several Orientations and a Horizontal Surface For S5 Deg North Latitude on August 1 ' Sun' Time . Northeast 5:07 6:00 7:00 8:00 9:00 10:00 11:00 12:00 IKK) 2:00 3:00 4K30 5:00 6:00 6:53 0 43 121 147 120 71 28. 26 25.5 23.5 21 17 11 4.5 0 Intensity of Solar Radiation. Btu per Sq Ft per Hour East Southeast South Southwest West Northwest Horizontal Surface 0 49 151 207. 194 152 94 26 25.5 23.5 21 17 11 4.5 0 0 27 97 155 169 156 129 , 84' 25.5 23.5 21 17.. 11 4.5 0 0 4.5 11 25 49 83 103 109 103 83 49 25 11 4.5 0 00 4.5 4.5 11 11 17 21 23.5 17 21 23.5 25.5 84 129 25.5 26 94 156 152 169 . 194 155 207 97 151 27 49 00 0 4.5 11 17 21 23.5 25.5 26 28 71 120 147 121 43 0 0 13 .72 151 ' 213 245 288 298 288 " 245 213 151. 72 13 0