Document 7Rwx7K9m95OROQOpL2BrvXzXj

276 , CHAPTER IS \ 1946 Guide Table 1. Typical Commercial Design Room Conditions for Summer Average, Peak Load* Type of Installation Dry-Bulb Temp Deluxe Application________ Normal Application............. 15 to 40 min Occupancy..... 78 ' 80 82 Wet-Bulb Temp 65.25; 67 68 Relative Humidity Per Cent 50 51 49 Grains Per Lb ' 72.7 ' 78.5 ' 80.0 Effective Temp 72.2 . 74.0 75.3 Values in Tablet are'for peak load-conditions. It is general practice to operate a system' at-approxi mately 76 F and 50 per cent relative humidity at other than peak load. , i. outside air temperature is usually in. excess of 20 .F, the effective outside temperature for normal heat transmission through walls and floors having substantial heat capacity is usually taken 5. to 10 deg below the design maximum outside temperature. For windows, however, the instantaneous value of outside temperature is used. This load is calculated in a manner similar to that described ini Chapter 14 (except that flow of heat is reversed) by means of the formula: Ht'-- ATJ 0e - t) (1) where ' ' '' Ht = heat transmitted through the material of wall, glass, floor, etc., Btu per hour. , A ~ 'net inside area of wall, glass, floor, etc., square feet. t = inside temperature, Fahrenheit degrees. . te = effective outside temperature, Fahrenheit degrees. U = coefficient of transmission of wall, glass, floor, etc,, from Tables 4 to 18, Chapter 6, Btu per (hour) (square foot) (Fahrenheit degree difference in temperature). Solar Heat Transmission Calculations of the solar heat transmitted^through walls and roofs are difficult because of periodic character of heat flow and time lag due to heat capacity of construction.- f - An illustration of the variation in radiation intensity on differently oriented surfaces is given in Fig., 1... The greater part of the radiation .intensity is always direct radiation from the sun.,., However, during the time when the sun is shining, any surface receives radiation of a lower . Table 2. ' Design Dry- and Wet-Bulb Temperatures, Wind Velocities, and ' -Wind Directions For June. July, August, and September - 1 1 SfcATl` 1 ClTT * Design Del-Bulb c Design , Wst-Buia 8ukmer Wind Velocitt . MPH Prevailing Summer Wind Direction Ala.. Birmingham.-:_____:____ :__:__ 95 78 ' 5.2 s .' ' Mobile- ---; ~ -------:-- - 95 - :80 . 8.6- sw . 105.. 76 . 6.0- w Ark___________ Little Rock......... ...... 95- 78 7.0 , NE Calif;________ _ Los Angeles- __ __ .. 90 70 6.0 SW ' 90 65 1L0 sw 95 '64-' : - 6.8 - '-s' ' iW 95 95 " .75 '78' 7.3 9.7 ' s sw ; D.-'C.......... Fla Washington-TM.___ ---______ ' '95 - ' 95 78 78 . 6.2 . 8.7 s. SW V ,Tampa.... ______ _________ 94 . : 79 7.0 ... E Cooling-Load 277 Table 2. Design Dry- and Wet-Bulb Temperatures, Wind Velocities, and Wind Directions for June, July, August, and September (Concluded) Stats ^ . Cnr Design Dbt-Bulb Design Wbt-Bclb Summer Wind Prevailins : Velocitt Summer Wind. MPH Direction Ga--............ Atlanta__ ________________ 95 Savannah.__ _____ .1: 95 76 78 95 65 111......___ -- Chicago... ____ .. . 95 Peoria__________________ - 95 75 76 Ind------------ Indianapolis.__________ _ --. 95 76 Des Moines..... .................... 95 .. 77' . Wichita.-!__________ ;____ 100 75 95 76 La..........: New Orleans_____________ 95 79 Shreveport-^_________ ____ 100 78 Maine__-- Portland. -- Mr! _______ 90. 95 . 73 78 Mass.______ Boston____ ______ _______ 92 75 95 - 75 Minn.___ -- Minneapolis......________ .. 95 : 75 Miss_______ . Vicksburg.___1............ .... --. .95 78 Mo________ Kansas City. - ___ _ 100 76 St. Louis.________________ 95 78 Mont.__ ___ Helena___________________ 95 67 Nebr____ -- Lincoln.--_______ ________ .95 Matt 95 75 . 65 n.'h............ Manchester______________ 90 73 N. J----- :-- > Trenton--__ __________-- .95 N. Y........... Alhany ' ' .'92 78 75 Buffalo... ------- -------- 93 75 New York_________ .: . 95 75 N. M______ ' Santa Fe ___ ____ --. 90 65 N.C............. Asheville.- .......... .. 90 -. 75 Wilmington___;.____ 95 79 N. Dak..:.:__ Bismarck......--__;_________ 95 73 95 : 78 Cleveland.-!...:................... - 95 , 75 OUa...-- Oklahoma City.__________ 101 76 Ore------------- Portland.-^........................... 90 ' 65 Pa. 95 - / 78 Pittsburgh_____ ;________ 95 75 R. I..._____ Providence-- : .................... .93 75 S. C..______ Charleston-. _1. .............. 95 . 80 Greenville. ___. .! . 95 ` 76 S. Dak.,^_ . -95 75 . Tenn-.......... Chattanooga_____ _______ 95 77 - Memphis___ - ' 95 . 78 100 78 El Paso.____ !.--___:...... 100 69 Galveston___________ :____ 95 . 80 - Houston__________ ;__ _-- 95 78 San Antonio.;.......___ r.....:... 100 ' 78 - Utah Salt Lake CityTM___ 92 63 Vt_______ ;... Burlington_______.-.___ --.. 90 73 Va...,,l__ ..._. 95 . 78 Richmond. ____ :!......... - ,95 78 Wash............ Seattle.__ ______ .......... ...... 85 65 - W. Va . Spokane__ ___...................... . 90 Parkersburg.__1____ ______ 95 . 65 75 . Wis____ i___ Madison________ __ !.....--. 95 75 . Milwaukee.____:................... . .95 75 Wyo_______ Cheyenne....................... --__ ,95 65 7.3 NW 7.8 SW 5.8 NW. 10.2 ' NE 8.2 S 9.0 SW 6.6 SW 11.0 S 8.0 ' SW .7.0 . sw . 6.2 s' ' 7.3 . s 6.9 sw 9.2 sw 10,3 . SW 8.4 SE 6.2 SW 9.5 s 9.4 , sw 7.3 sw 9.3 . - s. 7.4 W : i 5.6 NW ' 10.0 sw. 7.1 s 12.2 ; SW ! 12.9 sw 6.5 se : . 5.6 . se ; 7.8 sw 8.8 .. NW 6.6 sw . . 9.9 s ' . 10.1' s . 6.6 NW, 9.7-1 sw r 9.0 NW 10.0 NW 9.9 ' SW ' 6.8 - NE 7.6 . S - 6.5 . SW 7.5 SW 9.4 s 6.9 E 9.7 S' 7.7' s 7.4 SE 8.2 SE 8.9 s . 10.9 s 6.2 SW " 7.9 S' 6.5 sw 5.3 SE . 8.1 sw 10.4 . s . 9.2 1 s