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Thermodynamics for Dummies Index moist • Symbols • described, 288 ρ. See density dew point of, 292–294, 296–297 ε (effectiveness), 185–186, 189 enthalpy of, 295–297 humidity of, 290–292, 293–294, 295–297 ηP (propulsive effi ciency), 192 φ (relative humidity), 290–292 as nonreactive gas mixture, 278 water vapor in, amount of, 289 ηII (second-law effi ciency), 162–164 ω (specifi c humidity), 290–292 molecular mass of, 55 γ (specifi c weight), 22 thermodynamic properties of, 349 η . See thermal effi ciency treating as pure substance, 277 th air conditioning systems. See also refrigeration systems cooling and dehumidifying, 300–302 • A • heat exchangers in, 102 heating and humidifying, 297–300 A. See availability throttling valves in, 104 a (acceleration), 18, 62–63 air-fuel ratio (AFR), 312–314, 320 absolute pressure scale, 19 aluminum absolute zero temperature contracting upon freezing, 40 indicating zero energy, 10, 20 thermodynamic properties of, 349 zero entropy at, 37–38, 124 Amagat’s law, 283, 284–285 absorption cycle, 336–337 ammonia acceleration (a), 18, 62–63 absorption cycle using, 336 acceleration of gravity (g), 17 critical point properties of, 269, 350 acetylene, enthalpy of formation for, 309 Einstein cycle using, 337 adiabatic fl ame temperature, 321–324 thermodynamic properties of, 349 adiabatic process, 31, 65–66, 86–88, 139, apparent ideal-gas constant (R ), 281–282 169, 199, 224 m apparent molar mass (M ), 281–282 AFR (air-fuel ratio), 312–314, 320 m argon air. See also air-conditioning gas constant of, 55 systems; atmosphere molecular mass of, 55 in combustion reactions, 305–307 Atkinson cycle, 335 critical point properties of, 269, 350 COPYRIGHTEDatm (atmospheres), MATERIAL 40 dehumidifying, 300–302 atmosphere. See also air; atm dry, 288 boundary work against, 148 gas constant of, 55 as dead state environment, 146 heating, 297–300 as heat exchanger, in Brayton cycle, 172 humidifying, 297–300 as natural thermal reservoir, 113 as ideal gas, 268 pressure of, at sea level, 18 ideal-gas properties of, 341 228_9781118002919-bindex.indd8_9781118002919-bindex.indd 351351 66/28/11/28/11 112:162:16 AAMM 352 Thermodynamics For Dummies attractive (or binding) forces, 25–26, 267 regeneration used with, 184–186 availability (A) thermal effi ciency of, 181–182 balancing in a system, 156–159 Brayton/Rankine combined cycle, 338 in closed systems, 147–151 Btu (British thermal unit), 24, 157 decrease in energy availability principle, 112, 159 described, 114, 145, 146 • C • in open systems c. See specifi c heat balancing, 156–159 C (Celsius scale), 20, 21, 328 with steady fl ow, 151–154 calories, 24 with transient fl ow, 154–156 carbon dioxide (CO2) transferring critical point properties of, 269, 350 using heat transfer, 158 enthalpy of formation for, 309 using mass fl ow, 158–159 formed in combustion reactions, using work, 157–158 278, 304, 306 units for, 157 gas constant of, 55 molecular mass of, 55 thermodynamic properties of, 349 • B • carbon monoxide back work ratio, 174, 189, 228 enthalpy of formation for, 309 benzene, enthalpy of formation for, 309 formed in combustion reactions, 278, 306 binary vapor cycles, 339 Carnot cycle binding (or attractive) forces, 25–26, 267 coeffi cient of performance for, 249–250, 258 boilers described, 168–169, 328 described, 68–70 processes in, 169–170 enthalpy (H) for, 52–53, 69–70 thermal effi ciency of, 171 heat transfer rate for, 68–70 in T-s diagrams, 130 mass fl ow rate for, 69 Celsius, Anders (scientist), 328 in Rankine cycle, 222 Celsius (°C) scale, 20, 21, 328 bomb calorimeter, 318 centigrade scale, 328. See also boundary, 30 Celsius (°C) scale boundary work, 63–67, 131, 148, 151 chemical energy Brayton, George (mechanical engineer), 327 in combustion reactions, 307, 314 Brayton cycle. See also reverse described, 11, 26 Brayton cycle Clausius statement, 118–120 actual compared to ideal, 190–191 closed systems analyzing availability in, 147–151 constant specifi c heat method, combustion reactions in, 314, 318–320 175–178, 180–181 conservation of energy in, 78–80 variable specifi c heat method, conservation of mass in, 77–78 175, 178–181 described, 78, 92 described, 172, 327 with ideal gases intercooling and reheating used with, in adiabatic processes, 86–88 186–189 in constant-pressure processes, 82–84 irreversibility of, 182–183 in constant-temperature processes, 85–86 processes in, 173–175 in constant-volume processes, 81–82 228_9781118002919-bindex.indd8_9781118002919-bindex.indd 352352 66/28/11/28/11 112:162:16 AAMM Index 353 irreversibility in, 160–161 isentropic, 170 with liquids, 88–90 isothermal, 170 with solids, 88–90 condensers CO2. See carbon dioxide described, 70–71, 120, 127 coeffi cient of performance (COP) entropy increased by, 126–127 described, 120–121 in Rankine cycle, 222 for heat pumps, 262–263 conservation of energy. See also fi rst law for reverse Brayton cycle, 249–250 of thermodynamics for vapor compression system, 258 acceptance of, 329 cogeneration, 118 in closed systems, 78–80 cold-air standard assumption, 202 with compressors, 101–102 combined cycle, 118 described, 35–36 combined-cycle heat engines, 338 for ideal gases, 81–88 combustion reactions for liquids, 88–90 adiabatic fl ame temperature of, 321–324 mass and energy, balancing, 94–95 air in, 305–307 for solids, 88–90 air-fuel ratio, 312–314 with steady state processes, 95–97 in closed systems, 314, 318–320 with transient processes, 108 described, 13–14, 303–305 conservation of mass enthalpy of combustion for, 310–314 in closed systems, 77–78 enthalpy of formation for, 308–309 mass and energy, balancing, 94–95 general combustion reaction equation in open systems, 91–94 for, 305–307 constant specifi c heat heating value of fuel, 312 in Brayton cycle, 175–178, 180–181 hydrocarbons as fuels for, 304 in diesel cycle, 213–216 ideal-gas properties of combustion entropy for, 137, 138–139, 140–141 gases, 348 in Otto cycle, 202–204, 207 in open systems, 314, 315–317 in reverse Brayton cycle, 247–249 products of, 304 constant specifi c volume, of moist air, reactants in, 304 295–297 reference state for, 307 constant-enthalpy (isenthalpic) process in steady-fl ow systems, 314–317 described, 31 compressed liquid in heat pumps, 262 changing to saturated liquid, 46–47 in vapor compression system, 255 described, 43, 224 constant-entropy (isentropic) process entropy of, 132 in Brayton cycle, 173 linear interpolation used with, 51 calculating availability for, 149–151 compressed liquid water properties, 342 calculating entropy for, 139–143 compressibility chart, 267, 283–284 in Carnot cycle, 169, 170 compressibility factor (Z) described, 31 in ideal-gas law, 270–273, 282–288 entropy unchanged by, 126 for real-gas mixtures, 282–288 in heat pumps, 261 compression ratio, 200 in Rankine cycle, 224, 225 compressors in reverse Brayton cycle, 246, 247 described, 100–102 in vapor compression system, 254 effi ciency of, 190 228_9781118002919-bindex.indd8_9781118002919-bindex.indd 353353 66/28/11/28/11 112:162:16 AAMM 354 Thermodynamics For Dummies constant-pressure (isobaric) process density (ρ) in Brayton cycle, 173, 174 compressibility factor with, 270–271 described, 31 described, 21–22 in heat pumps, 261, 262 determining ideal gases from, 55, 267 ideal gases in, 82–84 units for, 21 with piston-cylinder device, 65 dew point, 292–293 in reverse Brayton cycle, 246, 247 Diesel, Rudolf (inventor and engineer), 328 in vapor compression system, 254, 255 diesel cycle constant-pressure specifi c heat, 28, 280–282 analyzing, 213–218 constant-temperature (isothermal) process described, 212, 328 calculating entropy for, 128–130 effi ciency of, 218–219 in Carnot cycle, 169 irreversibility of, 219–220 described, 31 processes of, 212–213 with ideal gases, 85–86 diesel fuel with piston-cylinder device, 65 analyzing combustion process using, constant-volume (isochoric or isometric) 318–320 process enthalpy of combustion for, 311 described, 31 enthalpy of formation for, 309 ideal gases in, 81–82 diffusers, 98–100 with piston-cylinder device, 66 dry ice, sublimation of, 26, 41 constant-volume specifi c heat, 28, 280–282 dry-bulb temperature, 289, 293–294, 295 conventions used in this book, 2, 5–6 cooling the air. See air conditioning systems COP (coeffi cient of performance) • E • described, 120–121 E. See energy for heat pumps, 262–263 effectiveness (ε), 185–186, 189 for reverse Brayton cycle, 249–250 Einstein cycle, 337 for vapor compression system, 258 endothermic reaction, 308 copper energy (E) contracting upon freezing, 40 availability of thermodynamic properties of, 349 balancing in a system, 156–159 critical point in closed systems, 147–151 described, 42–43, 224, 268–269 decrease in energy availability principle, properties of various materials, 269, 350 112, 159 cycles. See also specifi c cycles decrease in, proportional to increase in described, 32–33 entropy, 159 incomplete, 34 described, 114, 145, 146 in open systems with steady fl ow, 151–154 • D • in open systems with transient fl ow, Dalton’s law, 283, 285–287 154–156 dead state, 146 transferring using heat transfer, 158 decrease in energy availability principle, transferring using mass fl ow, 158–159 112, 159 transferring using work, 157–158 dehumidifying the air, 300–302 units for, 157 balancing with mass, 94–95 228_9781118002919-bindex.indd8_9781118002919-bindex.indd 354354 66/28/11/28/11 112:162:16 AAMM Index 355 chemical energy of formation, 308–309 in combustion reactions, 307, 314 for gas mixtures, 280–282 described, 11, 26 of moist air, 293–294, 295–297 conservation of. See conservation of
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