a. A heat pump is required to maintain a house at 18oC. i. If the outside temperature is -5oC, what is the maximum coefficient of performance that can be achieved assuming it runs on an ideal reverse Carnot cycle? ii. If the house loses 1500 kJ of heat every minute, what is the required power input to the pump, and what rate of heat is transferred from the low temperature reservoir? iii. Comment on the sustainability and cost implications for heating a house with a heat pump compared with electrical heating alone.
a. A heat pump is required to maintain a house at 18oC.
i. If the outside temperature is -5oC, what is the maximum coefficient of performance that can be achieved assuming it runs on an ideal reverse Carnot cycle?
ii. If the house loses 1500 kJ of heat every minute, what is the required power input to the pump, and what rate of heat is transferred from the low temperature reservoir?
iii. Comment on the sustainability and cost implications for heating a house with a heat pump compared with electrical heating alone.
b. 0.9 kg of helium is contained in a 2 m3 pressure vessel initially at 3 bar. 20 kJ of heat is added. Assuming ideal gas conditions determine the initial and the final temperatures and the entropy change of the helium during the process. For helium ? = 2.0769 ??/??? and ?? = 5.1926 ??/???.
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