1. The benefits of multistage compression. Limits

In a refrigeration machine or heat pump, the temperatures of the cold source q _F and the hot source q _C are far apart:

• or because, at approximately constant condensation temperature q _C , evaporation temperature q _F decreases (refrigeration machine for low-temperature cold production, freezing);

• or because, at approximately constant evaporation temperature q _F , condensation temperature q _C rises (heat pump for high-temperature heat production);

The compression ratio τ = p _C...