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 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.

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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Q) A Carnot heat engine receives heat from a reservoir at 800 °C at a rate of 12 kJ/s and rejects the waste heat to the ambient air at 27 °C. The half entire work output of the heat engine is used to drive a refrigerator that removes heat from the refrigerated space at -4°C and transfers it to the same ambient air at 27°C. Determine: (a) The maximum rate of heat removal from the refrigerated space. (b) The total rate of heat rejection to the ambient air.
1. A Carnot heat engine absorbs heat at a rate of 10 kJ/s from a source at 500°C and rejects the waste heat to the environment at 25°C. It is proposed that the heat engine will be used to drive a Carnot refrigerator that removes heat from the cooled space at -10°C and rejects it to the same environment at 25°C. i. Determine the minimum rate of heat removal from the cooled space.
A Carnot heat engine receives heat from a reservoir at 900⁰C at a rate of 700 kJ/min and rejects the waste heat to the ambient air at 27⁰C. The entire work output of the heat engine is used to drive a refrigerator that removes heat from the refrigerated space at -5⁰C and transfers it to the same ambient air at 27⁰C. Determine a) the maximum rate of heat removal from the refrigerated space and a) the total rate of heat rejection to the ambient air. Pls include illustration of cycle.
1. An inventor claims to have invented a heat engine that receives 750kJ of heat from a source at 400K and produces 250kJ of net work while rejecting the waste heat to a sink at 300K. Is this a reasonable claim? Why?
(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.
b) A Carnot heat engine receives heat at 890 K and rejects the waste heat to the environment at 30°C. The entire work output of the heat engine is used to drive a Carnot refrigerator that removes heat from the cooled space at -10°C at a rate of 280 kJ/min and rejects it to the same environment at 30°C. Determine (a) the rate of heat supplied to the heat engine and (b) the total rate of heat rejection to the environment
Since Lucas is an engineer familiar with thermodynamics. He decided to create his own heat engine at home to avoid paying for 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 pump to the heat engine to check the amount of power being produced. Assume that the heat pump will be used to warm his room to 25°C, while the outside temperature is at 5°C. Lucas’ rooms loses 85,000 kJ/hr of heat. And, 25% of the heat engine’s power output goes to the heat pump. How much diesel (in kg) needs to be burned by the heat engine to maintain the temperature in Lucas’ room? Assume carnot heat engine and heat pump. If the natural gas has a heating value of 22,000 BTU/lb. *Round off all answers to four decimal places*
a) A heat engine takes 325 kJ of heat from a 1000 K energy reservoir and also 125 kJ of waste heat It throws it into a 400K energy reservoir. Meanwhile, it releases an energy of 200 kJ. Is the cycle in which this heat engine operates reversible? Is it irreversible? Is it impossible? Why? b) An inventor designed a cooling device with an efficiency coefficient of 8.5 between -10°C indoor temperature and 25°C room temperature. He claims to be running his machine. Could this claim be true? Why?
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3. A heat engine operates between two reservoirs at 700°C and 20°C. One-half of the work output of the heat engine is used to drive a Carnot heat pump that removes heat from the cold surroundings at 2°C and transfers it to a house maintained at 22°C. If the house is losing heat at a rate of 52,000 kJ/h, determine the minimum rate of heat supply to the heat engine required to keep the house at 22°C.
A heat engine operates between two reservoirs at 800 and 20oC. Onehalf of the work output of the heat engine is used to drive a Carnot heatpump that removes heat from the cold surrounding at 2oC and transfersit to a house maintained at 22oC.If the house is losing heat at a rate of 62,000 kJ/h,Determine:a) The minimum rate of heat supply (kJ/h) to the heat enginerequired to keep the house at 22oC. b) The thermal efficiency of the heat engine, if the rate of heatsupply to the heat engine is 15,000 kJ/h. c) The total amount of entropy change of the surrounding by takinginto account both the heat engine and Carnot heat pump for the casesof i) and ii), respectively. d) The cyclic entropy change of the heat engine for the cases of i) andii), respectively.
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.