please help in these questions The electric motor of a heat pump transfers energ

Question

please help in these questions

The electric motor of a heat pump transfers energy as heat from the outdoors, which is at -8.0degreeC, to a room that is at 23degreeC. If the heat pump were a Carnot heat pump (a Carnot engine working in reverse), how much energy would be transferred as heat to the room for each joule of electric energy consumed? An air conditioner operating between 91 degree F and 63 degree F is rated at 4000 Btu/h cooling capacity. Its coefficient of performance is 27% of that of a Carnot refrigerator operating between the same two temperatures. What horsepower is required of the air conditioner motor?

Explanation / Answer

here we need to find out the coffecient of performance of the heat pump in part (i).

C.P = Qh/W = Th/(Th-Tc) = 23/(23-(-8)) = 0.7419 J of heat per joule of energy consumed.

in second part we need to find out the EER(energy efficicency ratio) = cooling power/electrical input .

CP =EER * 0.292.

0.27*(91/(91-63)) = 4000*0.292/input

input = 0.0000640575 watts

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