Heat engines & refrigerators worksheet with answers

A refrigerator removes heat from its cold space at a rate of 5.8 kW while its compressor uses 2 kW of power. Find the rate Q̇_H at which it rejects heat to the kitchen.

A heat engine takes in 800 kJ of heat from a hot reservoir and rejects 560 kJ to a cold reservoir in each cycle. Find the net work W it produces per cycle.

A heat engine works between a hot reservoir at 575 °C and a cold reservoir at 15 °C. It takes in 500 kJ of heat. Find the most work W_max it could possibly produce.

A reversible (Carnot) heat engine takes in 4800 kJ of heat from a reservoir at 675 °C and rejects 1585 kJ per cycle. Find the temperature T_L of the cold reservoir in °C.

A Carnot heat engine receives 160 kW of heat from a source at 900 °C and rejects heat to the surroundings at 27 °C. All of its work drives a Carnot refrigerator that removes heat from a freezer at 0 °C and also rejects heat to the surroundings at 27 °C. Find the rate Q̇_L at which heat is removed from the freezer.

A Carnot heat engine receives 190 kW of heat from a source at 400 °C and rejects heat to the surroundings at 20 °C. All of its work drives a Carnot refrigerator that removes heat from a freezer at -30 °C and also rejects heat to the surroundings at 20 °C. Find the rate Q̇_L at which heat is removed from the freezer.