A walk-in freezer is to be kept at −10∘C (263K) in a room whose air temperature is 35∘C (308K). Owing to imperfect insulation, heat leaks into the freezer at the rate of 4.2×105Jh−1.
(a) For an ideal reversible refrigerator operating between these two temperatures, calculate the minimum continuous electrical power input required (in watts).
(b) Under the same ideal conditions, determine the rate at which heat will be rejected to the room (in watts).
(c) If the actual refrigerator used has a COP equal to 40% of the ideal value, compute the actual electrical power input that must be supplied.