Document mByQJozGoKr7ejVNdRB3zxDYd

Heating Ventilating Air Conditioning Guide 1939 Thermal conductivity (heat transferred per unit time per unit area, and per degree per unit length)k g h* -- __. ---_<_.) L Surface coefficient of heat transfer. Film coefficient of heat transfer, Individual coefficient of heat transfer (heat transferred per unit time per unit area per degree)__________________________________________________________________--./ _g A / 11 - f. (In general / is not equal to k/L, where L is the actual thickness of the fluid film). Over-all coefficient of heat transfer, Thermal, transmittance per unit area (heat transferred per unit time per unit area per degree over-all)------------------------....U g Thermal transmission (heat transferred per unit time)-.............................. ........................q Thermal resistance (degrees per unit of heat transferred per unit time)...... ...................R Thermal resistivity.. A/k Vaporization values at constant pressure, Differences between values for saturated vapor and saturated liquid at the same pressure----------------------------------- Subscript fg Velocity.~~ V Volume (total)____________________________________________ _________________ _______ V Volume per unit time, Rate at which quantity of material passes through a machine, Quantity of heat per unit time, Quantity of heat per unit weight----------g Watt________________________________________________________________1-------------------- w Watthour.____________ _________________________________________ ..whr Weight of a major item, Total weight--------------------------------- ------- __W Weight rate, Weight per unit of power, Weight per unit of time.. Work (total) .W CONVERSION EQUATIONS Fahrenheit degrees = 9/5 (centigrade degrees) + 32. Centigrade degrees = 5/9 (Fahrenheit degrees -- 32). Absolute temperature, expressed in Fahrenheit degrees' = Fahrenheit degrees + 459.6. In heating and ventilating work, 460 is usually used. Absolute temperature, expressed in centigrade degrees = centigrade degrees + 273.1. 848 Chapter 4S. .Terminology Power, Heat and Work 1 ton refrigeration Latent heat of ice 1 Btu 1 watthour 1 kilowatthour 1 mean calorie 1 kilowatt (1000 watts) 1 horsepower 1 boiler horsepower Weight and'Volume lgal(U.S.) 1 British or Imperial gallon 1 cu ft l eu ft water at 60 F 1 cu ft water at 212 F 1 gal water at 60 F 1 gal water at 212 F 1 lb (avdp) 1 bushel 1 short ton 1 long ton Pressure 1 lb per square inch 1 oz per square inch 12.000 Btu per hour 200 Btu per minute = 143.33 Btu per pound ( 777.5 ft-lb = | 0.293 whr l 252.02 mean calories ( 2,655.2 ft-lb = I 3.415 Btu I 3600 joules l 860.648 mean calories ( 3,415 Btu .. I 3.52 lb water evaporated from | and at 212 F [ 34.16 lb water raised 100 F f 0.003968 Btu = j 3.085 ft-lb l 0.0011619 whr f 1.3405 hp = ( 56.92 Btu per minute l 44,252.7 ft-lb per minute 0.746 kw 42.44 Btu per minute 33.000 ft-lb per minute 550 ft-lb per second 33,471.9 Btu per hour 9.80 kwhr f 231 cu in. \ 0.13368 cu ft 277.274 cu in. / 7.4805 gal \ 1728 cu in. 62.37 lb 59.76 lb 8.34 lb 7.99 lb / 16 oz . \ 7000 grains 1.244 cu ft 2000 lb 22401b z.U41t> in. mercury at 62 r 2.309 ft water at 62 F 27.71 in. water at 62 F / 0.1276 in. mercury at 62 F \ 1.732 in. water at 62 F 849