Consider three reservoirs that are TH = 473.2 K, TL = 293.2 K and TI = 277.2 K. A Carnot heat engine can be reversed and used as either a heat pump or a refrigerator. In the case of a heat pump the heat flow to the higher temperature reservoir is the desired output and it is used to heat a room or building. In the case of the refrigerator the desired energy flow is the heat in from a region to be cooled. For the heat pump or refrigerator, the work input is provided by electricity. A region is to be cooled to a temperature of 277 K using a Carnot refrigerator. The heat that must be removed is 15,000 W. The heat rejected from the refrigerator is to a heat reservoir at TH. Consider the cooling for a period of 3 hours. Answer the following: a)Determine the electrical energy input to the Carnot refrigerator. b)Determine the Coefficient of Performance (COP, the efficiency) of this cooling system. c)Determine the entropy production for this this cooling system. In this case you should include the entropy production of the heat loss process from 277 K and to TH. d) The cost of electricity is $0.237/kWh. What is the cost to cool the room for 3 hours?
Consider three reservoirs that are TH = 473.2 K, TL = 293.2 K and TI = 277.2 K. A Carnot heat engine can be reversed and used as either a heat pump or a refrigerator. In the case of a heat pump the heat flow to the higher temperature reservoir is the desired output and it is used to heat a room or building. In the case of the refrigerator the desired energy flow is the heat in from a region to be cooled. For the heat pump or refrigerator, the work input is provided by electricity.
A region is to be cooled to a temperature of 277 K using a Carnot refrigerator. The heat that must be removed is 15,000 W. The heat rejected from the refrigerator is to a heat reservoir at TH. Consider the cooling for a period of 3 hours.
Answer the following:
a)Determine the electrical energy input to the Carnot refrigerator.
b)Determine the Coefficient of Performance (COP, the efficiency) of this cooling system.
c)Determine the entropy production for this this cooling system. In this case you should include the entropy production of the heat loss process from 277 K and to TH.
d) The cost of electricity is $0.237/kWh. What is the cost to cool the room for 3 hours?
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