# 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 heat powered Carnot refrigerator.  The heat that must be removed is 15,000 W.  The heat rejected from the refrigerator is to a heat reservoir at TL. The heat input to this device is from a reservoir  at TH.  This is a Carnot model of an absorber refrigeration system.  In it a Carnot heat engine operates between reservoirs at TH and TL.  The work output from this Carnot heat engine is the input to a Carnot refrigerator that operates between TI and TL. Consider the cooling for a period of 3 hours.  Answer the following: a)Determine the heat energy input to this Carnot refrigerator. b) The cost of the fuel to operate this system is $0.075/kWh. What is the cost to cool the room for 3 hours? Question Consider three reservoirs that are TH = 473.2 K, T= 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 heat powered Carnot refrigerator. The heat that must be removed is 15,000 W. The heat rejected from the refrigerator is to a heat reservoir at TL. The heat input to this device is from a reservoir at TH. This is a Carnot model of an absorber refrigeration system. In it a Carnot heat engine operates between reservoirs at TH and TL. The work output from this Carnot heat engine is the input to a Carnot refrigerator that operates between TI and TL. Consider the cooling for a period of 3 hours. Answer the following: a)Determine the heat energy input to this Carnot refrigerator. b) The cost of the fuel to operate this system is$0.075/kWh.  What is the cost to cool the room for 3 hours?

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