How does the basic refrigeration cycle work?

The refrigeration cycle is the fundamental principle of any refrigeration system:

The 4 stages of the cycle:

1. Compression: The compressor draws in low-pressure refrigerant gas (approximately 30-50 PSI) and compresses it to high pressure (150-300 PSI). The gas temperature rises to 70-90 °C
2. Condensation: The hot, high-pressure gas passes through the condenser where it releases heat (cooled by air or water). The refrigerant condenses into liquid at high pressure. Condensation temperature: approximately 35-45 °C
3. Expansion: The high-pressure liquid passes through the expansion valve (TXV or capillary tube). Pressure drops sharply, and part of the liquid vaporizes. The refrigerant temperature drops to -5 to -30 °C depending on the application
4. Evaporation: The cold refrigerant (liquid/gas mixture) passes through the evaporator. It absorbs heat from the medium being cooled (cold room, freezer, air conditioner), causing the remaining liquid to boil. The warm gas returns to the compressor

Efficiency: The Coefficient of Performance (COP) of a typical refrigeration system is 2.5 to 4.0 — for 1 kW of electricity, 2.5 to 4 kW of heat is moved.