Question

The motor in a refrigerator has a power of 202 W. If the freezing compartment is at 270 K and the outside air is at 293 K, and assuming the coefficient of performance of a Carnot refrigerator, what is the maximum amount of energy that can be extracted as heat from the freezing compartment in 9.78 min?

Answer 1

Given,

     Power input, P = 202W,Tc = 270 K; Th = 293 K

Work input in t = 9.78 min,

            W = P.t = 202*9.78*60 = 118533.6 J

Heat extracted from the freezer, Qc = ?

Heat ejected to the outside air, Qh

Coefficient of performance,

            CoP = Qc /W = Tc/(Th -Tc) = 270/23= 9.0

Therefore,   Qc = WxCoP =118533.6*9.0

                       = 1066802.4 J =1066.8kJ

I hope help you !!