Q: A manufacturer of ice cream freezers claims that its product has a
A manufacturer of ice cream freezers claims that its product has a coefficient of performance of 1.3 while freezing ice cream at 250 K when the surrounding environment is at 300 K. Is this claim valid...
See AnswerQ: In the absence of any friction and other irreversibility, can a
In the absence of any friction and other irreversibility, can a heat engine have an efficiency of 100 percent? Explain.
See AnswerQ: A heat pump designer claims to have an air-source heat
A heat pump designer claims to have an air-source heat pump whose coefficient of performance is 1.8 when heating a building whose interior temperature is 300 K and when the atmospheric air surrounding...
See AnswerQ: An air-conditioning system is used to maintain a house at
An air-conditioning system is used to maintain a house at a constant temperature of 20°C. The house is gaining heat from outdoors at a rate of 20,000 kJ/h, and the heat generated in the house from the...
See AnswerQ: A Carnot heat pump is used to heat and maintain a residential
A Carnot heat pump is used to heat and maintain a residential building at 75°F. An energy analysis of the house reveals that it loses heat at a rate of 2500 Btu/h per °F temperature difference between...
See AnswerQ: A refrigeration system uses a water-cooled condenser for rejecting the
A refrigeration system uses a water-cooled condenser for rejecting the waste heat. The system absorbs heat from a space at 25°F at a rate of 21,000 Btu/h. Water enters the condenser at 65°F at a rate...
See AnswerQ: A refrigeration system is to cool bread loaves with an average mass
A refrigeration system is to cool bread loaves with an average mass of 350 g from 30 to –10°C at a rate of 1200 loaves per hour with refrigerated air at –30°C. Taking the average specific and latent h...
See AnswerQ: A heat pump with a COP of 2.8 is used
A heat pump with a COP of 2.8 is used to heat an airtight house. When running, the heat pump consumes 5 kW of power. If the temperature in the house is 7°C when the heat pump is turned on, how long wi...
See AnswerQ: The average atmospheric pressure on earth is approximated as a function of
The average atmospheric pressure on earth is approximated as a function of altitude by the relation Patm = 101.325 (1 − 0.02256z)5.256, where Patm is the atmospheric pressure in kPa and z is the altit...
See AnswerQ: Consider a Carnot heat-engine cycle executed in a closed system
Consider a Carnot heat-engine cycle executed in a closed system using 0.025 kg of steam as the working fluid. It is known that the maximum absolute temperature in the cycle is twice the minimum absolu...
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