The air refrigeration system operates on the Joule cycle, which is also known as the reverse Brayton cycle or the Bell-Coleman cycle.
This thermodynamic cycle involves the following processes:
- Isentropic Compression: Air is compressed, increasing its temperature and pressure.
- Constant Pressure Cooling: Heat is removed from the compressed air at constant pressure.
- Isentropic Expansion: The cooled, high-pressure air is expanded, causing a significant drop in temperature. This is where the refrigeration effect is achieved.
- Constant Pressure Heating: The cold air absorbs heat from the refrigerated space at constant pressure.
Essentially, the air refrigeration system uses air as the working fluid, and by compressing, cooling, and then expanding that air, it produces a cooling effect. This makes it different from vapor compression systems that use refrigerants that undergo phase changes.
