A heat pump collects thermal energy from outside air at 5C and delivers it into

Question

A heat pump collects thermal energy from outside air at 5C and delivers it into a house at 40C.

Part A Determine the maximum coefficient of performance (the maximum coefficient is determined in the same way as for a thermodynamic engine).

Part B If the motor of the heating pump uses 1000 J of electrical energy to do work during a certain time interval, how much thermal energy is delivered into the house through heating, assuming the heating pump works at the maximum coefficient of performance?

Part C If the motor of the heating pump uses 1000 J of electrical energy to do work during a certain time interval, how much thermal energy is delivered into the house through heating, assuming the heating pump works at a coefficient of performance of 2.0.

Any help would be much appreciated.

Explanation / Answer

T must be in kelvin

Tc   = 5C = 273.15+5 = 278.15 K

TH   = 40+273.15 = 313.15 K

anf

COP = TH  / TH  - Tc   = 313.15 / 313.15 - 278.15 = 8.94714

Part C

COP = Qhot   / Qhot - Qhold

2 = Q + W / W   

2 = Q/W + 1

1 = Q/W

Q = W = 1000 J

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.