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 6.11, Problem 87P
In an effort to conserve energy in a heat-engine cycle, somebody suggests incorporating a refrigerator that will absorb some of the waste energy QL and transfer it to the energy source of the heat engine. Is this a smart idea? Explain.
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A heat pump operates with a Coefficient of Performance equal to 8. What is the COP if this cycle were to operate as a refrigerator?
Since Lucas is an engineer familiar with
thermodynamics. He decided to create his own
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electricity. He created a small, makeshift heat
engine for trial. The combustion of his fuel.
diesel, reaches a temperature of 750°C, while
waste heat is disposed to the atmosphere at
50°C.
He, then connected a generator and a heat
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heat pump will be used to warm his room to
25°C, while the outside temperature is at 5°C.
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25% of the heat engine's power output goes to
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Chapter 6 Solutions
Thermodynamics: An Engineering Approach
Ch. 6.11 - Describe an imaginary process that violates both...Ch. 6.11 - Describe an imaginary process that satisfies the...Ch. 6.11 - Describe an imaginary process that satisfies the...Ch. 6.11 - An experimentalist claims to have raised the...Ch. 6.11 - Prob. 5PCh. 6.11 - Consider the process of baking potatoes in a...Ch. 6.11 - What are the characteristics of all heat engines?Ch. 6.11 - What is the KelvinPlanck expression of the second...Ch. 6.11 - Is it possible for a heat engine to operate...Ch. 6.11 - Baseboard heaters are basically electric...
Ch. 6.11 - Does a heat engine that has a thermal efficiency...Ch. 6.11 - In the absence of any friction and other...Ch. 6.11 - Are the efficiencies of all the work-producing...Ch. 6.11 - Consider a pan of water being heated (a) by...Ch. 6.11 - Prob. 15PCh. 6.11 - Prob. 16PCh. 6.11 - A heat engine has a heat input of 3 104 Btu/h and...Ch. 6.11 - Prob. 18PCh. 6.11 - A 600-MW steam power plant, which is cooled by a...Ch. 6.11 - Prob. 20PCh. 6.11 - A heat engine with a thermal efficiency of 45...Ch. 6.11 - A steam power plant with a power output of 150 MW...Ch. 6.11 - An automobile engine consumes fuel at a rate of 22...Ch. 6.11 - Prob. 24PCh. 6.11 - Prob. 25PCh. 6.11 - A coal-burning steam power plant produces a net...Ch. 6.11 - An Ocean Thermal Energy Conversion (OTEC) power...Ch. 6.11 - What is the difference between a refrigerator and...Ch. 6.11 - Prob. 29PCh. 6.11 - In a refrigerator, heat is transferred from a...Ch. 6.11 - A heat pump is a device that absorbs energy from...Ch. 6.11 - Define the coefficient of performance of a...Ch. 6.11 - Define the coefficient of performance of a heat...Ch. 6.11 - Prob. 34PCh. 6.11 - A refrigerator has a COP of 1.5. That is, the...Ch. 6.11 - What is the Clausius expression of the second law...Ch. 6.11 - Show that the KelvinPlanck and the Clausius...Ch. 6.11 - Prob. 38PCh. 6.11 - Determine the COP of a heat pump that supplies...Ch. 6.11 - Prob. 40PCh. 6.11 - Prob. 41PCh. 6.11 - 6–42 An air conditioner removes heat steadily from...Ch. 6.11 - 6–43 A food department is kept at –12°C by a...Ch. 6.11 - A household refrigerator that has a power input of...Ch. 6.11 - When a man returns to his well-sealed house on a...Ch. 6.11 - Prob. 47PCh. 6.11 - Prob. 48PCh. 6.11 - 6–49 A heat pump is used to maintain a house at a...Ch. 6.11 - Prob. 50PCh. 6.11 - A household refrigerator runs one-fourth of the...Ch. 6.11 - Prob. 52PCh. 6.11 - Consider an office room that is being cooled...Ch. 6.11 - Prob. 54PCh. 6.11 - Refrigerant-134a enters the condenser of a...Ch. 6.11 - An inventor claims to have developed a resistance...Ch. 6.11 - Prob. 57PCh. 6.11 - A cold canned drink is left in a warmer room where...Ch. 6.11 - A block slides down an inclined plane with...Ch. 6.11 - Prob. 60PCh. 6.11 - Show that processes that use work for mixing are...Ch. 6.11 - Why does a nonquasi-equilibrium compression...Ch. 6.11 - Prob. 63PCh. 6.11 - Prob. 64PCh. 6.11 - Prob. 65PCh. 6.11 - Why are engineers interested in reversible...Ch. 6.11 - What are the four processes that make up the...Ch. 6.11 - Prob. 68PCh. 6.11 - Prob. 69PCh. 6.11 - Prob. 70PCh. 6.11 - Somebody claims to have developed a new reversible...Ch. 6.11 - Is there any way to increase the efficiency of a...Ch. 6.11 - Consider two actual power plants operating with...Ch. 6.11 - Prob. 74PCh. 6.11 - Prob. 75PCh. 6.11 - 6–76 A Carnot heat engine receives 650 kJ of heat...Ch. 6.11 - A Carnot heat engine operates between a source at...Ch. 6.11 - A heat engine operates between a source at 477C...Ch. 6.11 - Prob. 80PCh. 6.11 - Prob. 81PCh. 6.11 - In tropical climates, the water near the surface...Ch. 6.11 - 6–83 A well-established way of power generation...Ch. 6.11 - Prob. 84PCh. 6.11 - Prob. 85PCh. 6.11 - How can we increase the COP of a Carnot...Ch. 6.11 - In an effort to conserve energy in a heat-engine...Ch. 6.11 - Prob. 88PCh. 6.11 - Prob. 89PCh. 6.11 - 6–90 During an experiment conducted in a room at...Ch. 6.11 - Prob. 91PCh. 6.11 - An air-conditioning system operating on the...Ch. 6.11 - Prob. 93PCh. 6.11 - Prob. 94PCh. 6.11 - Prob. 95PCh. 6.11 - Prob. 96PCh. 6.11 - 6–97 A heat pump is used to maintain a house at...Ch. 6.11 - Prob. 98PCh. 6.11 - Prob. 99PCh. 6.11 - Prob. 100PCh. 6.11 - A commercial refrigerator with refrigerant-134a as...Ch. 6.11 - Prob. 102PCh. 6.11 - A heat pump is to be used for heating a house in...Ch. 6.11 - A Carnot heat pump is to be used to heat a house...Ch. 6.11 - A Carnot heat engine receives heat from a...Ch. 6.11 - Prob. 106PCh. 6.11 - Prob. 107PCh. 6.11 - Prob. 108PCh. 6.11 - Derive an expression for the COP of a completely...Ch. 6.11 - Prob. 110PCh. 6.11 - Prob. 111PCh. 6.11 - Prob. 112PCh. 6.11 - Prob. 113PCh. 6.11 - Someone proposes that the entire...Ch. 6.11 - Prob. 115PCh. 6.11 - Prob. 116PCh. 6.11 - Prob. 117PCh. 6.11 - It is often stated that the refrigerator door...Ch. 6.11 - Prob. 119RPCh. 6.11 - A Carnot heat pump is used to heat and maintain a...Ch. 6.11 - Prob. 121RPCh. 6.11 - Prob. 122RPCh. 6.11 - A refrigeration system uses a water-cooled...Ch. 6.11 - A heat pump with a COP of 2.8 is used to heat an...Ch. 6.11 - Prob. 125RPCh. 6.11 - Consider a Carnot refrigeration cycle executed in...Ch. 6.11 - Consider two Carnot heat engines operating in...Ch. 6.11 - Prob. 129RPCh. 6.11 - A heat engine operates between two reservoirs at...Ch. 6.11 - Prob. 132RPCh. 6.11 - An old gas turbine has an efficiency of 21 percent...Ch. 6.11 - Prob. 134RPCh. 6.11 - Prob. 135RPCh. 6.11 - Prob. 136RPCh. 6.11 - Prob. 137RPCh. 6.11 - Prob. 138RPCh. 6.11 - Prob. 139RPCh. 6.11 - A refrigeration system is to cool bread loaves...Ch. 6.11 - The drinking water needs of a production facility...Ch. 6.11 - Prob. 143RPCh. 6.11 - Prob. 145RPCh. 6.11 - Prob. 146RPCh. 6.11 - Prob. 147RPCh. 6.11 - Prob. 148RPCh. 6.11 - A heat pump with refrigerant-134a as the working...Ch. 6.11 - Prob. 150RPCh. 6.11 - Prob. 151RPCh. 6.11 - Prob. 153RPCh. 6.11 - Prob. 154RPCh. 6.11 - Prob. 155RPCh. 6.11 - A 2.4-m-high 200-m2 house is maintained at 22C by...Ch. 6.11 - Prob. 157FEPCh. 6.11 - Prob. 158FEPCh. 6.11 - A heat pump is absorbing heat from the cold...Ch. 6.11 - A heat engine cycle is executed with steam in the...Ch. 6.11 - A heat engine receives heat from a source at 1000C...Ch. 6.11 - Prob. 162FEPCh. 6.11 - A refrigeration cycle is executed with R-134a...Ch. 6.11 - A heat pump with a COP of 3.2 is used to heat a...Ch. 6.11 - A heat engine cycle is executed with steam in the...Ch. 6.11 - An air-conditioning system operating on the...Ch. 6.11 - Prob. 167FEPCh. 6.11 - Two Carnot heat engines are operating in series...Ch. 6.11 - Consider a Carnot refrigerator and a Carnot heat...Ch. 6.11 - A typical new household refrigerator consumes...Ch. 6.11 - A window air conditioner that consumes 1 kW of...
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- A heat pump operates with Refrigerant 134a as the working fluid. You are required to analyze its performance, and compare it with Camot heat pump. The data of the heat pump is as under: 23 - Thermodynamies-II Page 1 of 3 The heat pump is presently providing heating at a rate of 12 kW to maintain the interior of a building at 20°C. Outside temperature is 5°C. The refrigerant enters the compressor at 2.4 bar and increases the pressure to 8.0 bar. Efficiency of the compressor is 80%. a Temperatures at the principal states of the cycle, each °C b. Power input to the compressor, in kW c. Coefficient of performance Relate its performance with the specifications provided by the vendor i.e. COP = 8.5 and identify the possible reasons of differences. Draw Ts diagramarrow_forward(b) An irreversible heat pump with COP of 2.4 is used to heat water to 80°C for cleaning purposes. This heat pump absorbs heat from surrounding at 30°C and received the entire power, W from a Carnot heat engine operating between 250°C and 30°C. The Carnot heat engine received 6.3 kW of heat from the high temperature source. i) Draw the schematic diagram of the above system. ii) Determine the power received by the heat pump, W from Carnot heat engine, kW. iii) Calculate the rate of heat supplied to the water by the heat pump, kW. iv) Determine the COP of the heat pump if it operates on a reversed Carnot cycle.arrow_forwardA heat engine operates on a Carnot cycle with an efficiency of 75 percent. What COP would a refrigerator operating on the same cycle have? The low temperature is 0°C.arrow_forward
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