Carnot heat engine obtains 3000 kJ heat from a high-temperature reservoir at 850 deg C. It rejects the waste heat to a low-temperature reservoir at 75 deg C. The work produced by the Carnot heat engine is used to power up a reversible refrigerator that removes heat at a refrigerated space maintained at -10 deg C. The heat removed is discarded in the same low-temperature reservoir as that of the Carnot heat engine. The work net output of the combined heat engine and refrigerator plant is 400 kl. Determine the total heat rejection if the actual efficiency of the heat engine and COP of the refrigerator is 45% of the maximum possible values

Carnot heat engine obtains 3000 kJ heat from a high-temperature reservoir at 850 deg C. It rejects the waste heat to a low-temperature reservoir at 75 deg C. The work produced by the Carnot heat engine is used to power up a reversible refrigerator that removes heat at a refrigerated space maintained at -10 deg C. The heat removed is discarded in the same low-temperature reservoir as that of the Carnot heat engine. The work net output of the combined heat engine and refrigerator plant is 400 kl. Determine the total heat rejection if the actual efficiency of the heat engine and COP of the refrigerator is 45% of the maximum possible values

Refrigeration and Air Conditioning Technology (MindTap Course List)

8th Edition

ISBN:9781305578296

Author:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Publisher:John Tomczyk, Eugene Silberstein, Bill Whitman, Bill Johnson

Chapter45: Domestic Refrigerators And Freezers

Section: Chapter Questions

Problem 12RQ: Refrigerators currently being manufactured in the United States are using______as their refrigerant.

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Similar questions

a) A Carnot heat engine receives heat from a reservoir at 700 ° C at a rate of 600 kJ / min and rejects the waste heat to the ambient air at 25 ° C. The entire work output of the heat engine is used to drive a refrigerator that removes heat from the refrigerated space at - 6 ° C and transfers it to the same ambient air at 25 ° C. Determine (a) the maximum rate of heat removal from the refrigerated space and (b) the total rate of heat rejection to the ambient air.
A reversible heat engine drives the heat pump and takes in heat from a thermal energy reservoir at 1113K and dumps the heat to a reservoir at 333K. The heat pump works on a Carnot cycle and absorbs heat from the thermal energy reservoir at 278K and rejects the heat to a reservoir at 333K.The heat engine is also being used to operate a machine which takes in 30 kW. If the rate of extraction of the heat pump from its initial reservoir is at 17 kJ/s, calculate the ff:- What is the rate of extraction of heat from the heat engine? - What is the rate of the rejection of heat from the 333K reservoir?
A heat engine is operating on a Carnot cycle and has a thermal efficiency of 55 percent. The waste heat from this engine is rejected to a nearby lake at 60°C at a rate of 900 kJ/min. Determine the temperature of the source.
A CARNOT heat engine receives heat from a reservoir at 900°C at a rate of 800kJ/min and rejects the waste heat to the ambient air at 27°C. All the power produced by the thermal engine is used to act as a refrigerator that removes heat from the refrigerated space at -5°C and transfers it to the same ambient air at 27°C. Determine a) the maximum rate of heat removal from the refrigerated space and b) the total rate of heat rejection to the ambient air.
A Carnot heat engine receives heat from a reservoir at 900°C at a rate of 800 kJ/min and rejects the waste heat to the ambient air at 27°C. The entire work output of the heat engine is used to drive a refrigerator that removes heat from the refrigerated space at –5°C and transfers it to the same ambient air at 27°C. Determine the maximum rate of heat removal from the refrigerated space.
A reversibly operating heat engine operates between two reservoirs with temperatures between 600 ℃ and 40 ℃, and the heat energy supplied to the heat engine from the 600 ℃ reservoir is 2000 kJ. This heat engine operates a refrigerator that operates reversibly between two reservoirs with temperatures between 40°C and -20°C. Since the net work output of the whole system is 360 kJ; (a) Calculate the net amount of heat transferred to the refrigerator and the reservoir at 40℃. (The reservoir at 40℃ is common for both refrigerator and heat machine.) (b) What would happen if the heat engine and refrigerator were working at 40% efficiency rather than reversibly? Recalculate part (a) for this case.
A reversible heat engine operate between two reservoirs at temperature of 600°C and 40°C. The engine drives a reversible refrigerator which Operates between reservoirs at a temperature of 40°C and -20°C. The heat transfer to the heat engine is 2000KJ and the net work out put of the combined engine refrigerator plant is 260 KJ. Evaluate the heat transfer to the refrigerator and the net heat transfer to the refrigerator at 40°C.
A commercial refrigerator using R-134a as a refrigerant is used to keep the cooled environment at -35'C. The refrigerator releases the waste heat to the cooling water that enters the condenser at 18'C with a flow of 0.25 kg / s and leaves the condenser at 26'C. The refrigerant enters the condenser at a pressure of 1.2 MPa and a temperature of 50'C, and leaves the condenser at the same pressure and supercooled at 5 ₒC. Since the compressor consumes 3.3 kW of power, a) Mass flow rate of the refrigerant, b) Cooling load and COP value c) Calculate the minimum power consumed by the compressor for the same cooling load.
A heat engine is operating on a Carnot cycle and has a thermal efficiency of 55 percent. The waste heat from this engine is rejected to a nearby lake at 60°C at a rate of 900 kJ/min. Determine the power output of the engine
Prove that a refrigerator’s COP cannot exceed that of a completely reversible refrigerator that shares the same thermal energy reservoirs.
A heat engine operates on the Carnot cycle, and has a thermal efficiency of 75 percent. The waste heat from this machine is rejected to a nearby lake at 15 ° C at the rate of 14 kW. Determine the power output of the motor and the temperature of the source, in ° C.
A Carnot heat engine receives heat from a reservoir at 900°C at a rate of 800 kJ/min and rejects the waste heat to the ambient air at 27°C. The entire work output of the heat engine is used to drive a refrigerator that removes heat from the refrigerated space at –5°C and transfers it to the same ambient air at 27°C. Determine the total rate of heat rejection to the ambient air.