Document YjzQYBvNb9Qz9eKZ0N4oNrj2k

American Society of Heating and Ventilating Engineers Guide, 1936 Head................. ................................................................................................................................ H or h Heat content, Total heat, Enthalpy. (The capital should be used for any weight and the small letter for unit weight.)....... ....................................... ..... ........................ H or h Heat content of saturated liquid, Total heat of saturated liquid, Enthalpy of saturated liquid, sometimes called heat of the liquid-------------------------------- ----------- hi Heat content of dry saturated vapor, Total heat of dry saturated vapor, Enthalpy of dry saturated vapor........... ..................................................................................................... hz Heat of vaporization at constant pressure........................................................................ L or hig Horsepower........................................................................................................................ hp Horsepower-hour...................... ;.......... ............................................................. ............................hp-hr Inch........... ...... :...in. Inch-pound......... ............ in-lb Indicated horsepower................................................................................................................._........ihp 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....... .................................................................................. kg Kilowatt.................................................................................. kw Kilowatthour...... ..... ............................................................... :................ .................................. ...kwhr Length of path of heat flow,thickness.. ......................................................................................... L Load, total--......................................... W Massi................................... .......................... ........................................................................... m Mechanical efficiency.:................................ m- Mechanical equivalent of heat-- ................................. J Melting point........ .................................................... ..................... .............................................. . ..mp Meter................................................................ ...............................................................:...................... m Micron............ ...................................................................... ..................... .:...............................U- (mu) Miles per hour......................... mph Minute.... ......................................................................................................................................... :___ min Molecular weight................................................................................ ........................................mol. wt Mol.... ........ .................................................................. ...................................'..................................... mol Ounce................................................... i........ ..................................... ....... ............... :............................. oz Power, Horsepower, Work perunit 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................. _________________________________ .'........ ............... ................. Q 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............................................................. 1........................................:............. Subscript i Specific gravity.................................... ............................................................................................. sp gr Specific neat....... .:..... .......................................-................................--.....................................sp ht or c Specific heat at constant pressure............................................-- ....................... ............... .........--Cp Specific heat at constant volume.............. ..................................... ~-......................................---cv Specific volume, Volume per unit weight, Volume per unit mass................................;...........v 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.) --..................................... :----- -.t or ft (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 C- R kA L ti -- tj Thermal conductance per unit area, Unit conductance (heat transferred per unit time per unit area per degree) ................................................................................-- Ca C -C- 1 q Ca _ A RA A(t\ -- /*) k `Terms ending ivily designate properties independent of .size or. shape, sometimes called specific proper ties. Examples are--conductivity 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. ' 784 Chapter 44--Terminology Thermal conductivity (heat transferred per unit time per unit area, and per degree per unit length)......... ,........................................................... ................................ k g k = __--__ (6 ~ <). 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 (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) Thermal resistance (degrees per unit of heat transferred per unit time)............................ R Thermal resistivity..................... ...............................'................. .......................................................l/k - Vaporization values at constant pressure, Differences between values for saturated vapor and saturated liquid at the same pressure............................................ ..Subscript fe Velocity.... ..........:______________I.... .................................... ....................................... ......... ;............ .. 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........ . ..q Watt.................................................................... :......................................................................................w Watthour......--.......;............... ...................................................................... ..................................... whr Weight of a major item, Total weight.................................................. ......... .............................. W Weight rate, Weight per unit of power, Weight per unit of time..........................................w Work (total)..........C....__________________________ __________________________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 + Power, Heat, and Work Lton refrigeration Latent heat of ice _ (12,000 Btu per hour (200 Btu per minute = 143.33 Btu per pound 785