A household freezer operates in a room at 20°C. Heat must be transferred from the cold space at a rate of 2 kW to maintain its temperature at −30°C. What is the theoretically smallest (power) motor required to operate this freezer?
Assume a Carnot cycle between TL = -30°C and TH = 20°C:
This is the theoretical minimum power input. Any actual machine requires a larger input.
