Document evxdxDmX68gXDJo5mKOdqbBRq

American Society of Heating and Ventilating Engineers Guide, 1937 Head.. Heat content, Total heat, Enthalpy. (The capital should be used for any weight and the small letter for unit weight.)_____________ fj 0r, Heat content of saturated liquid, Total heat of saturated liquid, Enthalpy of saturated liquid, sometimes called heat of the liquid . Heat content of dry saturated vapor, Total heat of dry saturated vapor, Enthalpy ' 1 of dry saturated vapor.___________________ _______________________ ______ __ j Heat of vaporization at constant pressure......... ........... ................ ........................ X or L8 Horsepower__________________________ ________________ _1* Horsepower-hour.................................... ;................. ...................................................... hp^hr Inch..... ........ ....................... ............ ......... ........ ........ ............ ........................................ Inch-pound........................................... .......................................... ...... ........... _....... . n.-lb Indicated horsepower....................... :.................................................... ............................ jj, Indicated horsepower-hour.--____________ ____ ihp-hr Internal energy. Intrinsic energy. (The capital should be used for any weight and the small letter for unit weight.)______________ ______ ___________________ U or u Kilogram___________________________________________________________________ __ fo. Kilowatt_____ __________ .~......................................................_........... ........................... kw Kilowatthour................................................. kwhr Length of path of heat flow, thickness........................................................... ................... X Load, total........................ jy Mass.............. ............. Mechanical efficiency.. --- ---- m ..._ Mechanical equivalent of heat.................... ............... .... ;..................................................y Melting point................. _mp Meter... ......... m Micron.......... ............................................................. ....................................................p (mu) Miles per hour................... ........................................._................................................. ...mph Minute................ ......... .............................................................................. -.................... min Molecular weight......................................... ........................................... ....................mol. wt Mol--------------------------------------------- ----------------------------- 1............. ...... ........ ................mol Power, Horsepower, Work per unit time...................... P Pressure, Absolute pressure, Gage pressure, Force per unit area____________________ p Quantity (total) of fluid, water, gas, heat; Quantity by volume; Total quantity of heat transferred____ Quality of steam, Pounds of dry steam per pound of mixture. Revolutions per minute. ..rpm Saturated liquid at saturation pressure and temperature, Liquid in contact with vapor_______________________ _________________________________Subscript f Specific gravity............................. ....................... 1.... __________ __________________ sp gr Specific heat.................................................................................................... ..sp ht or c Specific heat at constant pressure.--..................................... .............. ....... ----------- cp Specific heat at constant volume................ .... ................... ......................... ---------------- Cy Specific volume, Volume per unit weight, Volume per unit mass____ __ Square foot____________________ ... ~sq ft Square inch___________________________________________________ _____________ sq in. Temperature (ordinary) F or C. (Theta is used preferably only when t is used for Time in the same discussion.)tof 8 (theta) Temperature (absolute) F abs or K. (Capital theta is used preferably only when small theta is used for ordinary temperature.)T or 0 (capital theta) Thermal conductance4 (heat transferred per unit time per degree).._________ _______-C 1 = kA = q R L ti -- it Thermal, conductance per unit area. Unit conductance (heat transferred per unit time per unit area per degree)................................................................... l RA A(h-/,) *Terms ending ivity designate properties independent of size or shape, sometimes called specific proper* ttes. Examples are--inductivity and resistivity. Terms ending once designate quantities depending not only on the material, but also upon size and shape, sometimes called total quantities. Examples are-- conductance and transmittance. Terms ending ion designate rate of heat transfer. Examples are--con-, duction and transmission. 800 Chapter 44--Terminology Thermal conductivity (heat transferred per unit time per unit area, and per degree per unit length)-------------- --------------------------------------- ----------------- ---- .k - 3 k --__ A___ (u - h) L Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual joefficient of heat transfer (heat transferred per unit time per unit area per degree)--................. ............................................. -.......................... -......................... -f A f ti -- tt (In general f 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 3 A Thermal transmission (heat transferred per unit time) 3 Thermal resistance (degrees per unit of heat transferred per unit time) R R= _L kA Thermal resistivity.. ------------ ----------------------------------------------- --------------------------1/k Vaporization values at constant pressure. Differences between values for saturated vapor and saturated liquid at the same pressure____________ __________Subscript * VVoolluummee (ptoertaul)n..i.t...t..im....e..,...R...a..t.e....a...t...w...h..i.c.h....q...u..a.n..t.i.t.y....o...f...m...a..t.e..r.i.a..l..p.a..s..s.e..s....t.h..r.o...u..g..h....a......... machine, Quantity of heat per unit time. Quantity of heat per unit weight......... Watt--__ ___ ___ ,............................................................................................................... Watthour..... ................................................................... ....................... ............................ w Weight of a major item, Total weight................... ............................................ ............. . Weight rate, Weight per unit of power, Weight per unit of time..................... .............. Work (total)...........................;........................................................... .................... .......... CONVERSION EQUATIONS Fahrenheit degrees = 9/5 (centigrade degrees + 32). Centigrade degrees =5/9 (Fahrenheit degrees -- 32). Absolute temperature, expressed in Fahrenheit degrees = Fahrenheit degrees -F 459.6. In heating and ventilating work, 460 is usually used.-- 27_AbsJute temperature, expressed in centigrade degrees = centigrade degrees -F` 801