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 23P
A freezer is maintained at 20°F by removing heat from it at a rate of 75 Btu/min. The power input to the freezer is 0.70 hp, and the surrounding air is at 75°F. Determine (a) the reversible power, (b) the irreversibility, and (c) the second-law efficiency of this freezer.
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A freezer is maintained at 20°F by removing heat from it at a rate of 75 Btu/min. The power input to the freezer is 0.70 hp, and the surrounding air is at 75°F. Determine the second-law efficiency of this freezer.
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A freezer is maintained at 20°F by removing heat from it at a rate of 75 Btu/min. The power input to the freezer is 0.70 hp, and the surrounding air is at 75°F. Determine\ the reversible power.
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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- 3. A heat engine receives heat from a source at 1000 K at a rate of 450 kJ/s and rejects the waste heat to a medium at 200 K. The power output of the heat engine is 160 kW. Determine the reversible work and irreversibility rate for this process.arrow_forwardShow that the work produced by a reversible process exceeds that produced by an equivalent irreversible process by considering a weight moving down a plane both with and without friction.arrow_forwardAn ordinary household refrigerator receives electrical work from its surroundings while discharging energy by heat transfer to its surroundings. Is this a violation of the Kelvin-Planck statement? Explain. Discuss about factors causing irreversibility.arrow_forward
- Obtain a relation for the second-law efficiency of a heat engine that receives heat QH from a source at temperature TH and rejects heat QL to a sink at TL, which is higher than T0 (the temperature of the surroundings), while producing work in the amount of W.arrow_forwardA refrigeration cycle operating between hot and cold reservoirs at 40°C and 0°C removes energy by heat transfer from the cold reservoir at a rate of 200 kW and requires 50 kW of power to transfer the heat to the hot reservoir. Determine whether the cycle is reversible, irreversible, or impossible.arrow_forwardA refrigerator is removing heat from a cold medium at 3°C at a rate of 7200 kJ/h and rejecting the waste heat to a medium at 30°C. If the coefficient of performance of the refrigerator is 2, the power consumed by the refrigerator amounts to kW (round off to 2 decimal places). The maximum COP of the refrigerator is (round off to 2 decimal places), if the processes that occurred were reversible.arrow_forward
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