2. Compression heat pumps with internal combustion engine

A heat engine consumes fuel in order to transform part of its calorific value into mechanical energy (25 to 42% of ICP depending on engine type and speed). The rest of the energy is recovered in the form of heat at various temperature levels:

• high exhaust gas temperatures (450 to 800°C);

• medium temperatures (85 to 95°C) in cooling water ;

• low temperatures (20 to 40°C) in the air surrounding the engine.

When we use a heat engine to drive the compressor of a heat pump, only the energy recovered from the air has a low enough temperature level to contribute directly to the heat pump's cold source. As for other heat sources, it is preferable to recover them from the heat transfer fluid in the circuit. Thanks to the heat pump's use of energy from...