A refrigeration machine is a device that transfers heat from a low-temperature region to a high-temperature region through physical or chemical methods, thereby achieving a cooling effect. Its core principle is based on the reverse Carnot cycle or vapor compression cycle in thermodynamics.
The working principle of a refrigeration machine is mainly based on the reverse Carnot cycle (ideal model) or the vapor compression cycle (practical application). Taking the vapor compression cycle as an example, its core is to achieve heat transfer through the phase change process of the refrigerant (such as Freon, ammonia, carbon dioxide, etc.):
Compression Stage: The compressor compresses the low-temperature, low-pressure gaseous refrigerant into a high-temperature, high-pressure gas. This process consumes electrical energy and increases the refrigerant temperature.
Condensation Stage: The high-temperature, high-pressure gas enters the condenser, where it releases heat to the external environment through heat dissipation (such as air cooling or water cooling), and the refrigerant condenses into a high-pressure liquid.
Throttling Stage: The high-pressure liquid is throttled through an expansion valve or capillary tube, causing a sudden drop in pressure that leads to partial vaporization of the liquid, absorbing surrounding heat and cooling down.
Evaporation stage: Low-temperature, low-pressure liquid refrigerant enters the evaporator, absorbs heat from the target space (such as a cold storage room) and completely vaporizes, completing the cooling process. Subsequently, the gaseous refrigerant returns to the compressor for circulation.