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 6.11, Problem 102P
An air-conditioning system is used to maintain a house at 70°F when the temperature outside is 100°F. The house is gaining heat through the walls and the windows at a rate of 800 Btu/min, and the heat generation rate within the house from people, lights, and appliances amounts to 100 Btu/min. Determine the minimum power input required for this air-conditioning system.
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An air-conditioning system is used to maintain a house at 70°F when the temperature outside is 100°F. The house is gaining heat through the walls and the windows at a rate of 800 Btu/min, and the heat generation rate within the house from people, lights, and appliances amounts to 100 Btu/min. Determine the minimum power input required for this airconditioning system.
A heat pump is used to extract heat from the outside atmosphere to heat the inside of a building.
On a day when the outside air temperature is Tc°C, the heat pump is operating to a COP of 2.7, maintaining the inside temperature of the building at Th°C.
If the building is losing heat at the rate of 62,893 kJ/hour in these conditions, determine how much power (kW) must be supplied to a heat pump.
A heat pump is used to extract heat from the outside atmosphere to heat the inside of a building.
On a day when the outside air temperature is Tc°C, the heat pump is operating to a COP of 3.7, maintaining the inside temperature of the building at Th°C.
If the building is losing heat at the rate of 53,709 kJ/hour in these conditions, determine how much power (kW) must be supplied to a heat pump? Keep two decimal places
Chapter 6 Solutions
Thermodynamics: An Engineering Approach
Ch. 6.11 - A mechanic claims to have developed a car engine...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 - Consider the process of baking potatoes in a...Ch. 6.11 - Prob. 7PCh. 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 - 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 - Baseboard heaters are basically electric...Ch. 6.11 - Consider a pan of water being heated (a) by...Ch. 6.11 - A heat engine has a total heat input of 1.3 kJ and...Ch. 6.11 - A steam power plant receives heat from a furnace...Ch. 6.11 - A heat engine has a heat input of 3 104 Btu/h and...Ch. 6.11 - A 600-MW steam power plant, which is cooled by a...Ch. 6.11 - A heat engine with a thermal efficiency of 45...Ch. 6.11 - A heat engine that propels a ship produces 500...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 - Solar energy stored in large bodies of water,...Ch. 6.11 - A coal-burning steam power plant produces a net...Ch. 6.11 - An Ocean Thermal Energy Conversion (OTEC) power...Ch. 6.11 - Prob. 27PCh. 6.11 - Prob. 29PCh. 6.11 - What is the difference between a refrigerator and...Ch. 6.11 - Prob. 31PCh. 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 - In a refrigerator, heat is transferred from a...Ch. 6.11 - A heat pump is a device that absorbs energy from...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 - The coefficient of performance of a residential...Ch. 6.11 - A food freezer is to produce a 5-kW cooling...Ch. 6.11 - An automotive air conditioner produces a 1-kW...Ch. 6.11 - A food refrigerator is to provide a 15,000-kJ/h...Ch. 6.11 - Prob. 44PCh. 6.11 - Determine the COP of a heat pump that supplies...Ch. 6.11 - Prob. 46PCh. 6.11 - A heat pump with a COP of 1.4 is to produce a...Ch. 6.11 - An air conditioner removes heat steadily from 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 - Water enters an ice machine at 55F and leaves as...Ch. 6.11 - A refrigerator is used to cool water from 23 to 5C...Ch. 6.11 - A household refrigerator runs one-fourth of the...Ch. 6.11 - Consider an office room that is being cooled...Ch. 6.11 - A house that was heated by electric resistance...Ch. 6.11 - Refrigerant-134a enters the condenser of a...Ch. 6.11 - Refrigerant-134a enters the evaporator coils...Ch. 6.11 - An inventor claims to have developed a resistance...Ch. 6.11 - Prob. 60PCh. 6.11 - Why are engineers interested in reversible...Ch. 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. 64PCh. 6.11 - Prob. 65PCh. 6.11 - Show that processes that use work for mixing are...Ch. 6.11 - Why does a nonquasi-equilibrium compression...Ch. 6.11 - Prob. 68PCh. 6.11 - Prob. 69PCh. 6.11 - What are the four processes that make up the...Ch. 6.11 - Prob. 71PCh. 6.11 - Prob. 72PCh. 6.11 - Prob. 73PCh. 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 - You are an engineer in an electric-generation...Ch. 6.11 - Prob. 78PCh. 6.11 - A thermodynamicist claims to have developed a heat...Ch. 6.11 - A heat engine is operating on a Carnot cycle and...Ch. 6.11 - A completely reversible heat engine operates with...Ch. 6.11 - An inventor claims to have developed a heat engine...Ch. 6.11 - A Carnot heat engine operates between a source at...Ch. 6.11 - A heat engine is operating on a Carnot cycle and...Ch. 6.11 - A heat engine operates between a source at 477C...Ch. 6.11 - An experimentalist claims that, based on his...Ch. 6.11 - In tropical climates, the water near the surface...Ch. 6.11 - Prob. 89PCh. 6.11 - Prob. 90PCh. 6.11 - Prob. 91PCh. 6.11 - Prob. 92PCh. 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. 95PCh. 6.11 - Prob. 96PCh. 6.11 - A thermodynamicist claims to have developed a heat...Ch. 6.11 - Determine the minimum work per unit of heat...Ch. 6.11 - Prob. 99PCh. 6.11 - An air-conditioning system operating on the...Ch. 6.11 - A heat pump operates on a Carnot heat pump cycle...Ch. 6.11 - An air-conditioning system is used to maintain a...Ch. 6.11 - A Carnot refrigerator absorbs heat from a space at...Ch. 6.11 - Prob. 104PCh. 6.11 - A Carnot refrigerator operates in a room in which...Ch. 6.11 - Prob. 106PCh. 6.11 - A commercial refrigerator with refrigerant-134a as...Ch. 6.11 - Prob. 108PCh. 6.11 - A heat pump is to be used for heating a house in...Ch. 6.11 - A completely reversible heat pump has a COP of 1.6...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. 113PCh. 6.11 - Derive an expression for the COP of a completely...Ch. 6.11 - Calculate and plot the COP of a completely...Ch. 6.11 - Prob. 116PCh. 6.11 - Prob. 117PCh. 6.11 - Prob. 118PCh. 6.11 - Someone proposes that the entire...Ch. 6.11 - Prob. 120PCh. 6.11 - Prob. 121PCh. 6.11 - Prob. 122PCh. 6.11 - It is commonly recommended that hot foods be...Ch. 6.11 - It is often stated that the refrigerator door...Ch. 6.11 - Prob. 125RPCh. 6.11 - Prob. 126RPCh. 6.11 - Prob. 127RPCh. 6.11 - A Carnot heat pump is used to heat and maintain a...Ch. 6.11 - A refrigeration system uses a water-cooled...Ch. 6.11 - A refrigeration system is to cool bread loaves...Ch. 6.11 - A heat pump with a COP of 2.8 is used to heat an...Ch. 6.11 - Prob. 132RPCh. 6.11 - Consider a Carnot heat-engine cycle executed in a...Ch. 6.11 - Prob. 134RPCh. 6.11 - Consider a Carnot refrigeration cycle executed in...Ch. 6.11 - Prob. 137RPCh. 6.11 - Consider two Carnot heat engines operating in...Ch. 6.11 - A heat engine operates between two reservoirs at...Ch. 6.11 - An old gas turbine has an efficiency of 21 percent...Ch. 6.11 - Prob. 141RPCh. 6.11 - Prob. 142RPCh. 6.11 - Prob. 143RPCh. 6.11 - The drinking water needs of a production facility...Ch. 6.11 - Prob. 145RPCh. 6.11 - Prob. 147RPCh. 6.11 - Prob. 148RPCh. 6.11 - Prob. 149RPCh. 6.11 - Prob. 150RPCh. 6.11 - Prob. 151RPCh. 6.11 - A heat pump with refrigerant-134a as the working...Ch. 6.11 - Prob. 153RPCh. 6.11 - Prob. 155RPCh. 6.11 - Prob. 156RPCh. 6.11 - Prob. 157RPCh. 6.11 - Prove that a refrigerators COP cannot exceed that...Ch. 6.11 - Consider a Carnot refrigerator and a Carnot heat...Ch. 6.11 - A 2.4-m-high 200-m2 house is maintained at 22C by...Ch. 6.11 - A window air conditioner that consumes 1 kW of...Ch. 6.11 - The drinking water needs of an office are met by...Ch. 6.11 - The label on a washing machine indicates that the...Ch. 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 pump cycle is executed with R134a under the...Ch. 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 - A heat engine receives heat from a source at 1000C...Ch. 6.11 - An air-conditioning system operating on the...Ch. 6.11 - A refrigerator is removing heat from a cold medium...Ch. 6.11 - Two Carnot heat engines are operating in series...Ch. 6.11 - A typical new household refrigerator consumes...
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- A food compartment is to be maintained at 21°C by a refrigeration system. The total cooling load of the food compartment is estimated to be 330 kJ/h and the heat rejection by the condenser is 480 kJ/h. The outdoor air temperature is 35°C. draw the schematic diagram of the refrigeration system determine the power input required to operate the refrigeration system in kW.arrow_forwardBy supplying energy to a house at a rate of 25,000 kJ/hr, a heat pump maintains the temperature of the dwelling at 20 C when the outside air is at -10 C. If electricity costs 8 cents per kW-hr, determine the minimum theoretical operating cost to heat the house for 24 hours. $1.97 O $1.37 $1.75 O $1.51 O$1.64arrow_forwardThe coefficient of performance of a residential heat pump is 1.6. Calculate the heating effect in kJ/s this heat pump will produce when it consumes 2 kW of electrical power.arrow_forward
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