Questions from Thermal Fluid Science


Q: A heat pump is a device that absorbs energy from the cold

A heat pump is a device that absorbs energy from the cold outdoor air and transfers it to the warmer indoors. Is this a violation of the second law of thermodynamics? Explain.

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Q: What is the Clausius expression of the second law of thermodynamics?

What is the Clausius expression of the second law of thermodynamics?

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Q: Show that the Kelvin–Planck and the Clausius expressions of the

Show that the Kelvin–Planck and the Clausius expressions of the second law are equivalent.

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Q: The average temperature of the atmosphere in the world is approximated as

The average temperature of the atmosphere in the world is approximated as a function of altitude by the relation Tatm = 288.15 − 6.5z where Tatm is the temperature of the atmosphere in K and z is the...

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Q: A food freezer is to produce a 5-kW cooling effect

A food freezer is to produce a 5-kW cooling effect, and its COP is 1.3. How many kW of power will this refrigerator require for operation?

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Q: Describe an imaginary process that satisfies the second law but violates the

Describe an imaginary process that satisfies the second law but violates the first law of thermodynamics.

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Q: An automotive air conditioner produces a 1-kW cooling effect while

An automotive air conditioner produces a 1-kW cooling effect while consuming 0.75 kW of power. What is the rate at which heat is rejected from this air conditioner?

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Q: A food refrigerator is to provide a 15,000-kJ

A food refrigerator is to provide a 15,000-kJ/h cooling effect while rejecting 22,000 kJ/h of heat. Calculate the COP of this refrigerator.

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Q: Determine the COP of a refrigerator that removes heat from the food

Determine the COP of a refrigerator that removes heat from the food compartment at a rate of 5040 kJ/h for each kW of power it consumes. Also, determine the rate of heat rejection to the outside air....

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Q: Determine the COP of a heat pump that supplies energy to a

Determine the COP of a heat pump that supplies energy to a house at a rate of 8000 kJ/h for each kW of electric power it draws. Also, determine the rate of energy absorption from the outdoor air.

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