Thermodynamics: An Engineering Approach
8th Edition
ISBN: 9780073398174
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Textbook Question
Chapter 5.5, Problem 58P
Why are throttling devices commonly used in refrigeration and air-conditioning applications?
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1. A refrigeration system using R-22 has a capacity of 320 kW of refrigeration.
The evaporating temperature is -10°C and the condensing temperature is
40°C. Calculate the fraction of vapor in the mixture before the evaporator.
Properties of R-22:
At -10°C; hg = 401.60 kJ/kg, hf = 188.43 kJ/kg
At 40°C; hf 249.69 kJ/kg
A Freon 12 vapour compression system operating at a condenser temperature of
40°C and an evaporator temperature of 0°C develops 15 tons of refrigeration.
Using the p-h diagram for Freon 12, determine.
(a) the discharge temperature and mass flow rate of the refrigerant circulated,
The catalogue for a refrigerant 22, four-cylinder, hermetic compressor operating at 29 r/s. a condensing temperature of 40 °C and an evaporating temperature of -4 °C shows a refrigeration capacity of 96.4 kW. At this operating points the motor (whose efficiency is 90 percent) draws 28.9 kW. The bore of the cylinders is 87 mm and the piston stroke is 70 mm. The performance data are based on 8 °C of subcooling of the liquid leaving the condenser. Compute 3.1 the actual volumetric efficiency and 3.2 the compression efficiency.
Chapter 5 Solutions
Thermodynamics: An Engineering Approach
Ch. 5.5 - Prob. 1PCh. 5.5 - Define mass and volume flow rates. How are they...Ch. 5.5 - Does the amount of mass entering a control volume...Ch. 5.5 - Consider a device with one inlet and one outlet....Ch. 5.5 - The ventilating fan of the bathroom of a building...Ch. 5.5 - 5–6E Air whose density is 0.078 lbm/ft3 enters the...Ch. 5.5 - 5–7 Air enters a 28-cm diameter pipe steadily at...Ch. 5.5 - A steady-flow compressor is used to compress...Ch. 5.5 - A 2-m3 rigid tank initially contains air whose...Ch. 5.5 - 5–10 A cyclone separator like that in Fig. P5–10...
Ch. 5.5 - 5–11 A spherical hot-air balloon is initially...Ch. 5.5 - A desktop computer is to be cooled by a fan whose...Ch. 5.5 - 5–13 A pump increases the water pressure from 100...Ch. 5.5 - Refrigerant-134a enters a 28-cm-diameter pipe...Ch. 5.5 - Prob. 15PCh. 5.5 - Prob. 16PCh. 5.5 - 5–17C What is flow energy? Do fluids at rest...Ch. 5.5 - How do the energies of a flowing fluid and a fluid...Ch. 5.5 - Prob. 19PCh. 5.5 - Prob. 20PCh. 5.5 - Refrigerant-134a enters the compressor of a...Ch. 5.5 - Steam is leaving a pressure cooker whose operating...Ch. 5.5 - A diffuser is an adiabatic device that decreases...Ch. 5.5 - The kinetic energy of a fluid increases as it is...Ch. 5.5 - Prob. 25PCh. 5.5 - Air enters a nozzle steadily at 50 psia, 140F, and...Ch. 5.5 - The stators in a gas turbine are designed to...Ch. 5.5 - The diffuser in a jet engine is designed to...Ch. 5.5 - Air at 600 kPa and 500 K enters an adiabatic...Ch. 5.5 - Prob. 30PCh. 5.5 - Prob. 31PCh. 5.5 - Air at 13 psia and 65F enters an adiabatic...Ch. 5.5 - Carbon dioxide enters an adiabatic nozzle steadily...Ch. 5.5 - Refrigerant-134a at 700 kPa and 120C enters an...Ch. 5.5 - Prob. 35PCh. 5.5 - Refrigerant-134a enters a diffuser steadily as...Ch. 5.5 - Prob. 38PCh. 5.5 - Air at 80 kPa, 27C, and 220 m/s enters a diffuser...Ch. 5.5 - 5–40C Consider an air compressor operating...Ch. 5.5 - Prob. 41PCh. 5.5 - Somebody proposes the following system to cool a...Ch. 5.5 - 5–43E Air flows steadily through an adiabatic...Ch. 5.5 - Prob. 44PCh. 5.5 - Prob. 45PCh. 5.5 - Steam flows steadily through an adiabatic turbine....Ch. 5.5 - Prob. 48PCh. 5.5 - Steam flows steadily through a turbine at a rate...Ch. 5.5 - Prob. 50PCh. 5.5 - Carbon dioxide enters an adiabatic compressor at...Ch. 5.5 - Prob. 52PCh. 5.5 - 5–54 An adiabatic gas turbine expands air at 1300...Ch. 5.5 - Prob. 55PCh. 5.5 - Prob. 56PCh. 5.5 - Air enters the compressor of a gas-turbine plant...Ch. 5.5 - Why are throttling devices commonly used in...Ch. 5.5 - Would you expect the temperature of air to drop as...Ch. 5.5 - Prob. 60PCh. 5.5 - During a throttling process, the temperature of a...Ch. 5.5 - Refrigerant-134a is throttled from the saturated...Ch. 5.5 - A saturated liquidvapor mixture of water, called...Ch. 5.5 - Prob. 64PCh. 5.5 - A well-insulated valve is used to throttle steam...Ch. 5.5 - Refrigerant-134a enters the expansion valve of a...Ch. 5.5 - Prob. 68PCh. 5.5 - Consider a steady-flow heat exchanger involving...Ch. 5.5 - Prob. 70PCh. 5.5 - Prob. 71PCh. 5.5 - Prob. 72PCh. 5.5 - Prob. 73PCh. 5.5 - Prob. 74PCh. 5.5 - Prob. 76PCh. 5.5 - Steam is to be condensed on the shell side of a...Ch. 5.5 - Prob. 78PCh. 5.5 - Air (cp = 1.005 kJ/kgC) is to be preheated by hot...Ch. 5.5 - Prob. 80PCh. 5.5 - Refrigerant-134a at 1 MPa and 90C is to be cooled...Ch. 5.5 - Prob. 82PCh. 5.5 - An air-conditioning system involves the mixing of...Ch. 5.5 - The evaporator of a refrigeration cycle is...Ch. 5.5 - Steam is to be condensed in the condenser of a...Ch. 5.5 - Steam is to be condensed in the condenser of a...Ch. 5.5 - Two mass streams of the same ideal gas are mixed...Ch. 5.5 - Prob. 89PCh. 5.5 - A 110-volt electrical heater is used to warm 0.3...Ch. 5.5 - The fan on a personal computer draws 0.3 ft3/s of...Ch. 5.5 - Prob. 92PCh. 5.5 - 5–93 A scaled electronic box is to be cooled by...Ch. 5.5 - Prob. 94PCh. 5.5 - Prob. 95PCh. 5.5 - Prob. 96PCh. 5.5 - Prob. 97PCh. 5.5 - A computer cooled by a fan contains eight PCBs,...Ch. 5.5 - Prob. 99PCh. 5.5 - A long roll of 2-m-wide and 0.5-cm-thick 1-Mn...Ch. 5.5 - Prob. 101PCh. 5.5 - Prob. 102PCh. 5.5 - A house has an electric heating system that...Ch. 5.5 - Steam enters a long, horizontal pipe with an inlet...Ch. 5.5 - Refrigerant-134a enters the condenser of a...Ch. 5.5 - Prob. 106PCh. 5.5 - Water is heated in an insulated, constant-diameter...Ch. 5.5 - Prob. 108PCh. 5.5 - Air enters the duct of an air-conditioning system...Ch. 5.5 - A rigid, insulated tank that is initially...Ch. 5.5 - 5–113 A rigid, insulated tank that is initially...Ch. 5.5 - Prob. 114PCh. 5.5 - A 0.2-m3 rigid tank equipped with a pressure...Ch. 5.5 - Prob. 116PCh. 5.5 - Prob. 117PCh. 5.5 - Prob. 118PCh. 5.5 - Prob. 119PCh. 5.5 - An air-conditioning system is to be filled from a...Ch. 5.5 - Oxygen is supplied to a medical facility from ten...Ch. 5.5 - Prob. 122PCh. 5.5 - A 0.3-m3 rigid tank is filled with saturated...Ch. 5.5 - Prob. 124PCh. 5.5 - Prob. 125PCh. 5.5 - Prob. 126PCh. 5.5 - The air-release flap on a hot-air balloon is used...Ch. 5.5 - An insulated 0.15-m3 tank contains helium at 3 MPa...Ch. 5.5 - An insulated 40-ft3 rigid tank contains air at 50...Ch. 5.5 - A vertical pistoncylinder device initially...Ch. 5.5 - A vertical piston-cylinder device initially...Ch. 5.5 - Prob. 135RPCh. 5.5 - Prob. 136RPCh. 5.5 - Air at 4.18 kg/m3 enters a nozzle that has an...Ch. 5.5 - An air compressor compresses 15 L/s of air at 120...Ch. 5.5 - 5–139 Saturated refrigerant-134a vapor at 34°C is...Ch. 5.5 - A steam turbine operates with 1.6 MPa and 350C...Ch. 5.5 - Prob. 141RPCh. 5.5 - Prob. 142RPCh. 5.5 - Prob. 143RPCh. 5.5 - Steam enters a nozzle with a low velocity at 150C...Ch. 5.5 - Prob. 146RPCh. 5.5 - Prob. 147RPCh. 5.5 - Prob. 148RPCh. 5.5 - Prob. 149RPCh. 5.5 - Cold water enters a steam generator at 20C and...Ch. 5.5 - Prob. 151RPCh. 5.5 - An ideal gas expands in an adiabatic turbine from...Ch. 5.5 - Prob. 153RPCh. 5.5 - Prob. 154RPCh. 5.5 - Prob. 155RPCh. 5.5 - Prob. 156RPCh. 5.5 - Prob. 157RPCh. 5.5 - Prob. 158RPCh. 5.5 - Prob. 159RPCh. 5.5 - Prob. 160RPCh. 5.5 - Prob. 161RPCh. 5.5 - Prob. 162RPCh. 5.5 - Prob. 163RPCh. 5.5 - The ventilating fan of the bathroom of a building...Ch. 5.5 - Determine the rate of sensible heat loss from a...Ch. 5.5 - An air-conditioning system requires airflow at the...Ch. 5.5 - The maximum flow rate of standard shower heads is...Ch. 5.5 - An adiabatic air compressor is to be powered by a...Ch. 5.5 - Prob. 171RPCh. 5.5 - Prob. 172RPCh. 5.5 - Prob. 173RPCh. 5.5 - Prob. 174RPCh. 5.5 - Prob. 175RPCh. 5.5 - A tank with an internal volume of 1 m3 contains...Ch. 5.5 - A liquid R-134a bottle has an internal volume of...Ch. 5.5 - Prob. 179RPCh. 5.5 - Prob. 181RPCh. 5.5 - Prob. 182RPCh. 5.5 - Prob. 184RPCh. 5.5 - A pistoncylinder device initially contains 1.2 kg...Ch. 5.5 - In a single-flash geothermal power plant,...Ch. 5.5 - The turbocharger of an internal combustion engine...Ch. 5.5 - A building with an internal volume of 400 m3 is to...Ch. 5.5 - Prob. 189RPCh. 5.5 - Prob. 190RPCh. 5.5 - Prob. 191RPCh. 5.5 - Prob. 192FEPCh. 5.5 - Prob. 193FEPCh. 5.5 - An adiabatic heat exchanger is used to heat cold...Ch. 5.5 - A heat exchanger is used to heat cold water at 15C...Ch. 5.5 - An adiabatic heat exchanger is used to heat cold...Ch. 5.5 - In a shower, cold water at 10C flowing at a rate...Ch. 5.5 - Prob. 198FEPCh. 5.5 - Hot combustion gases (assumed to have the...Ch. 5.5 - Steam expands in a turbine from 4 MPa and 500C to...Ch. 5.5 - Steam is compressed by an adiabatic compressor...Ch. 5.5 - Refrigerant-134a is compressed by a compressor...Ch. 5.5 - Prob. 203FEPCh. 5.5 - Prob. 204FEPCh. 5.5 - Air at 27C and 5 atm is throttled by a valve to 1...Ch. 5.5 - Steam at 1 MPa and 300C is throttled adiabatically...Ch. 5.5 - Air is to be heated steadily by an 8-kW electric...
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