Thermodynamics: An Engineering Approach
9th Edition
ISBN: 9781259822674
Author: Yunus A. Cengel Dr., Michael A. Boles
Publisher: McGraw-Hill Education
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Chapter 8.8, Problem 89RP
To determine
The second-law of efficiency of the process.
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The pressure of saturated water vapor in an insulated tank with a volume of 5.7 m3 is 350 kPa. The tank is connected to the superheated steam pipe with a valve. The pressure of the superheated steam flowing in the pipe is 2.8 MPa and the temperature is 580oC. By opening the valve, the pressure of the water vapor in the tank is filled until it reaches 2.8 MPa. Calculate the second law efficiency of the filling process.
Refrigerant-22 absorbs heat from a cooled space at 50°F as it flows through an evaporator of a refrigeration system. R-22 enters the evaporator at 10°F at a rate of 0.08 lbm/s with a quality of 0.3 and leaves as a saturated vapor at the same pressure. Determine the second-law efficiency of the evaporator. Take T0 = 77°F. The properties of R-22 at the inlet and exit of the evaporator are: h1 = 107.5 Btu/lbm, s1 = 0.2851 Btu/lbm·R, h2 = 172.1 Btu/ lbm, s2 = 0.4225 Btu/lbm·R.
A well-insulated 4-m * 4-m * 5-m room initially at 10C is heated by the radiator of a steam-heating system. The radiator has a volume of 15 L and is filled with superheated vapor at 200 kPa and 200C. At this moment both the inlet and the exit valves to the radiator are closed. A 120-W fan is used to distribute the air in the room. The pressure of the steam is observed to drop to 100 kPa after 30 min as a result of heat transfer to the room. Assuming constant specific heats for air at room temperature, determine (a) the average temperature of air in 30 min, (b) the entropy change of the steam, (c) the entropy change of the air in the room, and (d) the entropy generated during this process, in kJ/K. Assume the air pressure in the room remains constant at 100 kPa at all times.
Chapter 8 Solutions
Thermodynamics: An Engineering Approach
Ch. 8.8 - What final state will maximize the work output of...Ch. 8.8 - Is the exergy of a system different in different...Ch. 8.8 - Under what conditions does the reversible work...Ch. 8.8 - How does useful work differ from actual work? For...Ch. 8.8 - How does reversible work differ from useful work?Ch. 8.8 - Is a process during which no entropy is generated...Ch. 8.8 - Consider an environment of zero absolute pressure...Ch. 8.8 - It is well known that the actual work between the...Ch. 8.8 - Consider two geothermal wells whose energy...Ch. 8.8 - Consider two systems that are at the same pressure...
Ch. 8.8 - Prob. 11PCh. 8.8 - Does a power plant that has a higher thermal...Ch. 8.8 - Prob. 13PCh. 8.8 - Saturated steam is generated in a boiler by...Ch. 8.8 - One method of meeting the extra electric power...Ch. 8.8 - A heat engine that receives heat from a furnace at...Ch. 8.8 - Consider a thermal energy reservoir at 1500 K that...Ch. 8.8 - A heat engine receives heat from a source at 1100...Ch. 8.8 - A heat engine that rejects waste heat to a sink at...Ch. 8.8 - A geothermal power plant uses geothermal liquid...Ch. 8.8 - A house that is losing heat at a rate of 35,000...Ch. 8.8 - A freezer is maintained at 20F by removing heat...Ch. 8.8 - Prob. 24PCh. 8.8 - Prob. 25PCh. 8.8 - Prob. 26PCh. 8.8 - Can a system have a higher second-law efficiency...Ch. 8.8 - A mass of 8 kg of helium undergoes a process from...Ch. 8.8 - Which is a more valuable resource for work...Ch. 8.8 - Which has the capability to produce the most work...Ch. 8.8 - The radiator of a steam heating system has a...Ch. 8.8 - A well-insulated rigid tank contains 6 lbm of a...Ch. 8.8 - A pistoncylinder device contains 8 kg of...Ch. 8.8 - Prob. 35PCh. 8.8 - Prob. 36PCh. 8.8 - Prob. 37PCh. 8.8 - A pistoncylinder device initially contains 2 L of...Ch. 8.8 - A 0.8-m3 insulated rigid tank contains 1.54 kg of...Ch. 8.8 - An insulated pistoncylinder device initially...Ch. 8.8 - Prob. 41PCh. 8.8 - An insulated rigid tank is divided into two equal...Ch. 8.8 - A 50-kg iron block and a 20-kg copper block, both...Ch. 8.8 - Prob. 45PCh. 8.8 - Prob. 46PCh. 8.8 - Prob. 47PCh. 8.8 - A pistoncylinder device initially contains 1.4 kg...Ch. 8.8 - Prob. 49PCh. 8.8 - Prob. 50PCh. 8.8 - Prob. 51PCh. 8.8 - Air enters a nozzle steadily at 200 kPa and 65C...Ch. 8.8 - Prob. 54PCh. 8.8 - Prob. 55PCh. 8.8 - Argon gas enters an adiabatic compressor at 120...Ch. 8.8 - Prob. 57PCh. 8.8 - Prob. 58PCh. 8.8 - The adiabatic compressor of a refrigeration system...Ch. 8.8 - Refrigerant-134a at 140 kPa and 10C is compressed...Ch. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Combustion gases enter a gas turbine at 900C, 800...Ch. 8.8 - Steam enters a turbine at 9 MPa, 600C, and 60 m/s...Ch. 8.8 - Refrigerant-134a is condensed in a refrigeration...Ch. 8.8 - Prob. 66PCh. 8.8 - Refrigerant-22 absorbs heat from a cooled space at...Ch. 8.8 - Prob. 68PCh. 8.8 - Prob. 69PCh. 8.8 - Air enters a compressor at ambient conditions of...Ch. 8.8 - Hot combustion gases enter the nozzle of a...Ch. 8.8 - Prob. 72PCh. 8.8 - A 0.6-m3 rigid tank is filled with saturated...Ch. 8.8 - Prob. 74PCh. 8.8 - Prob. 75PCh. 8.8 - An insulated vertical pistoncylinder device...Ch. 8.8 - Liquid water at 200 kPa and 15C is heated in a...Ch. 8.8 - Prob. 78PCh. 8.8 - Prob. 79PCh. 8.8 - A well-insulated shell-and-tube heat exchanger is...Ch. 8.8 - Steam is to be condensed on the shell side of a...Ch. 8.8 - Prob. 82PCh. 8.8 - Prob. 83PCh. 8.8 - Prob. 84PCh. 8.8 - Prob. 85RPCh. 8.8 - Prob. 86RPCh. 8.8 - An aluminum pan has a flat bottom whose diameter...Ch. 8.8 - Prob. 88RPCh. 8.8 - Prob. 89RPCh. 8.8 - A well-insulated, thin-walled, counterflow heat...Ch. 8.8 - Prob. 92RPCh. 8.8 - Prob. 93RPCh. 8.8 - Prob. 94RPCh. 8.8 - Prob. 95RPCh. 8.8 - Nitrogen gas enters a diffuser at 100 kPa and 110C...Ch. 8.8 - Prob. 97RPCh. 8.8 - Steam enters an adiabatic nozzle at 3.5 MPa and...Ch. 8.8 - Prob. 99RPCh. 8.8 - A pistoncylinder device initially contains 8 ft3...Ch. 8.8 - An adiabatic turbine operates with air entering at...Ch. 8.8 - Steam at 7 MPa and 400C enters a two-stage...Ch. 8.8 - Prob. 103RPCh. 8.8 - Steam enters a two-stage adiabatic turbine at 8...Ch. 8.8 - Prob. 105RPCh. 8.8 - Prob. 106RPCh. 8.8 - Prob. 107RPCh. 8.8 - Prob. 108RPCh. 8.8 - Prob. 109RPCh. 8.8 - Prob. 111RPCh. 8.8 - A passive solar house that was losing heat to the...Ch. 8.8 - Prob. 113RPCh. 8.8 - A 4-L pressure cooker has an operating pressure of...Ch. 8.8 - Repeat Prob. 8114 if heat were supplied to the...Ch. 8.8 - Prob. 116RPCh. 8.8 - A rigid 50-L nitrogen cylinder is equipped with a...Ch. 8.8 - Prob. 118RPCh. 8.8 - Prob. 119RPCh. 8.8 - Prob. 120RPCh. 8.8 - Reconsider Prob. 8-120. The air stored in the tank...Ch. 8.8 - Prob. 122RPCh. 8.8 - Prob. 123RPCh. 8.8 - Prob. 124RPCh. 8.8 - Prob. 125RPCh. 8.8 - Prob. 126RPCh. 8.8 - Prob. 127RPCh. 8.8 - Water enters a pump at 100 kPa and 30C at a rate...Ch. 8.8 - Prob. 129RPCh. 8.8 - Prob. 130RPCh. 8.8 - Obtain a relation for the second-law efficiency of...Ch. 8.8 - Writing the first- and second-law relations and...Ch. 8.8 - Prob. 133RPCh. 8.8 - Keeping the limitations imposed by the second law...Ch. 8.8 - Prob. 135FEPCh. 8.8 - Prob. 136FEPCh. 8.8 - Prob. 137FEPCh. 8.8 - Prob. 138FEPCh. 8.8 - A furnace can supply heat steadily at 1300 K at a...Ch. 8.8 - A heat engine receives heat from a source at 1500...Ch. 8.8 - Air is throttled from 50C and 800 kPa to a...Ch. 8.8 - Prob. 142FEPCh. 8.8 - A 12-kg solid whose specific heat is 2.8 kJ/kgC is...
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