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. Efficiency of the Carnot engine is 38%. For this information answer the following questions: 1) A room is maintained at a constant temperature of 20 C and has a heat loss of 20,000 W. Consider this room for a period of 3 hours. The surroundings are at a temperature of TI. In one option the room is heated using resistive heaters that are operated with electricity. For the same conditions described in part 1 above, consider using a Carnot heat pump to supply the heat to the room. The low temperature reservoir in this case is TI and the high temperature reservoir is the room temperature. Answer the following: a)Determine the electrical energy input to the Carnot heat pump. b)Determine the Coefficient of Performance (COP, the efficiency) of this heating system. c)Determine the entropy production for this this heating system. In this case you should include the entropy production of the heat loss process to TI. d) The cost of electricity is $0.237/kWh. What is the cost to heat 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. Efficiency of the Carnot engine is 38%. For this information answer the following questions:
1) A room is maintained at a constant temperature of 20 C and has a heat loss of 20,000 W. Consider this room for a period of 3 hours. The surroundings are at a temperature of TI. In one option the room is heated using resistive heaters that are operated with electricity.
For the same conditions described in part 1 above, consider using a Carnot heat pump to supply the heat to the room. The low temperature reservoir in this case is TI and the high temperature reservoir is the room temperature.
Answer the following:
a)Determine the electrical energy input to the Carnot heat pump.
b)Determine the Coefficient of Performance (COP, the efficiency) of this heating system.
c)Determine the entropy production for this this heating system. In this case you should include the entropy production of the heat loss process to TI.
d) The cost of electricity is $0.237/kWh. What is the cost to heat the room for 3 hours?
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