Document yrgQXeMO1ngDJ7r76OMYjbewd

HEATING VENTILATING AIR CONDITIONING GUIDE 1944 I V Vacuum ' cooling unit, 474 heating pumps. 274 control. 275 piston displacement, 276 heating systems. 268, 820 down-feed, 270 unit heater connection, 421 Vacuum dryer, 734 Valve, valves. 339 . angle, 295, 296, 339 automatic, 341 check, 339 . control. 296 expansion. 478 . gate; 339 globe, 339 . reducing pressure, 293 Vane, vanes,- 583 Vaned. outlets. 586 Vapor, vapors heating system, 820 unit heater connection, 421 pressure, 820 . Vaporizing oil burner, 213 - .Velocity, 820. s exhaust grilles, 590 ' method duct design, 606 * pressure, 820 return grilles, 360, 363, 590 Ventilation, 820 air conditioning units, 430 dairy bam, 758 garage, 789 hospitals, 684 natural, 751 - ; general rules. 757 . passenger bus in'summer, 701 physiological objectives of, 65 .railway passenger car, 697 ship, 842; - - . State codes, 832 symbols for drawings. 826" systems^ 383 * * wind forces, 751 Ventilator, ventilators control, 757 roof, 756 -unit;'423 - control. 649 .Vertical blow unit beater, 416 Vertical openings,-124 sealing, of, 124 . , _ . . - Vibration, machine,.635 - Viscous filters, 556 ; automatic, 557 . impingement, -556' ; Vitiation of air,-41 - Volume ~ ^control, 402 furnace, 179 .'spedfic; 818' . ... w . . Wall, walls * heat flow, through,. 153 . \heaf.transfer coefficients, 99, 103, 105 -- infiltration through, 118 time,lag of solar radiation; 154' Warm Air* gravity-heating system, 358 - . ;: design procedure, 362,364 .-.* ' - 'furnace capacity, 367 " . * ^Installation practice, 358, 369 - ; performance, 368 > - standardized units,-362, 363 * - unit carrying, capacity, 365; 366, 367- Warm air (continued) mechanical heating system, 371 automatic control. 375 cooling methods. 380 cooling system design, 381 dampers, 375 design procedure, 376 duct velocities, 377 ducts, 375. fans, 373 filters, 373 furnace, 371 heavy duty, 379 selection, 378 humidification, 379 motors, 373 registers and grilles, 374 panel heating, 788. 789 radiant heating, 788 radiators. 218 Washer, washers, 521 air, 813 - .-- * . Water atmospheric cooling equipment, 530 coils, 496 control temperature service, 809 cooled condenser, 480 - unit conditioning, 434 corrosion treatment, 341 r heater .. . coal-fired. 808. solar,'810 * , heating, 801, 805 'make-up, 544 maximum, main temperature, 528 ~ , properties of, 472 supply, piping,-801 _ . arrangement, 802 thermodynamics of, 1 well, temperatures, 527. .. Water vapor, 6 saturation pressure, 6 - '' specific enthalpy, 7 specific volume, 7 .. ' \- Welding, 323. 334, 336 Wet-bulb temperature, 532,820](see'lTemperalure) Wet return, 264, 820 '" Wind, winds forces, 751r754 . due to stack effect, 752 natural draff equipment, 535 selection of,, velodty, 137 - . -; Window; windows * coefficients of transmission, 115 leakage, 120 f- solar radiation through, 154i 155 - ventilators, 427 ' . v*- - . Winter * -- air conditioning system, 383 comfort zone, 57 ^ freezing, equipment, 544 __ Wound rotor motor. 673 Wrought-iron pipe, 324 . Wrought-steel pipe, 323 ' ' - /. - ~- .. ` _ . -' . *- . X-Y-2 Year 'round air conditioning system, 383. 652 Zone control, 647 evaporative regulation,' 60 Zoning, 400 control, 647 dual duct, 402 multiple fans, 401 recodling, 401 reheat, 401 . -' separate equipment, 401 ' volume control,- 402 ; . .. - . r . ... * ,M CHAPTER 1 ill,ermocL^namicS _and 'bUater ^Yjlxtuted Dry Air, Specific Enthalpy, Water Vapor, Moist Air, Dalton's Law, Humidity Ratio, RelativeHumidity, Dew-Point, Enthalpy, Thermodynamic Wet-bulb Temperature, Mollier Diagram, Typical Air Conditioning Processes, Adiabatic Saturation, Psychrometric Chart, Steady Flow Energy Equation, U. S. Standard Atmosphere THE working substance of the air conditioning engineer may be regarded, for the purpose of analysis, as a mixture of only two constituents, dry air and water. The mixture may consist of two, and possibly three distinct phases, solid, liquid and vapor. The vapor phase is conveniently referred to as moist air and is regarded as a mixture of dry air and water vapor. DRY AIR CompositionDry air is itself a mixture of several gases, but its composition is subject to such slight variation that it may be regarded as fixed. According to International Critical Tables, the mol-fraction composition of dry air is given by the first column of figures in Table 1. Molecular weights are given in the second column; the last figure in the third column is the apparent molecular weight of the mixture; the fourth column of figures gives the ordinary weight-fraction composition. It is well known that dry air contains other gases besides those listed in Table 1; but these are present in such minute amounts that they can be grouped together as argon. Values in the lower section of Table 1 give the approximate mol-fraction composition of what is called argon in the upper portion of the table. In physical and chemical thermodynamics, there is a distinct advan tage in using a different unit of weight, the mol, for each different sub stance involved. A mol of oxygen weighs 32.000 lb as a matter of defi nition ; a mol of^tny other substance is a weight, in pounds, equal to its molecular weight. Specific Volume and Density The ratio of total volume to total weight is called specific volume, v. In the English system, volume is expressed in cubic feet and weight in pounds; hence, specific volume is expressed in cubic feet per pound. The reciprocal of specific volume, that is, weight per unit volume is called weight density, d. The unit of density-is the pound per cubic foot. 1