A heat pump is used to keep a house warm at 22C. Part A:How much work is require

Question

A heat pump is used to keep a house warm at 22C.

Part A:How much work is required of the pump to deliver 3400 J of heat into the house if the outdoor temperature is 0C. Assume a COP of 3.0.

Part B:How much work is required of the pump to deliver 3400 J of heat into the house if the outdoor temperature is -15C? Assume a COP of 3.0.

Part C:How much work is required of the pump to deliver 3400 J of heat into the house if the outdoor temperature is 0C. Assume an ideal (Carnot) coefficient of performance COP = TH/(THTL).

Explanation / Answer

given

Th = 22 + 273 = 299 k

Tc = 0 + 273 = 273 k

and COP = 3
a)
we know,
COP = Qhot/W

==> W = Qhot/COP

= 3400/3

= 1133.3 J <<<<<<<------------Answer

B) same. 1133.3 J <<<<<<<------------Answer

C) COP = Th/(Th - Tc)

= 299/(299-273)

= 11.5

W = Qhot/COP

= 3400/11.5

= 295.6 J <<<<<<<------------Answer

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