Summary
Highlights
The refrigeration cycle is the foundational principle behind all types of AC systems, from small units to large chillers. Its primary function is to absorb and reject heat. According to the law of thermodynamics, cooling is achieved by removing heat from a substance, rather than directly cooling it. This cycle is also known as a heat pump cycle, utilizing refrigerant as the key material for heat removal.
The refrigeration cycle consists of four crucial components: the compressor, condenser, expansion valve, and evaporator.
The compressor increases the pressure of the refrigerant, enabling it to circulate throughout the system. Refrigerant enters the compressor as a low-pressure, low-temperature vapor and exits as a high-pressure, high-temperature vapor.
The condenser coil acts as a heat exchanger, cooling the high-temperature refrigerant from the compressor. As heat is released, the refrigerant changes from a vapor to a liquid state, exiting the condenser as high-pressure, low-temperature liquid.
The expansion valve, typically a thermal or electronic expansion valve, reduces the high pressure of the refrigerant received from the condenser. This pressure reduction also lowers the refrigerant's temperature. The refrigerant leaves the expansion valve as a low-temperature, low-pressure liquid.
The evaporator is another heat exchanger. Here, the low-temperature, low-pressure liquid refrigerant absorbs heat from the air blown across its fins, providing cooled air. This heat absorption causes the refrigerant to change from a liquid to a vapor state. The now vaporized refrigerant then returns to the compressor, completing the cycle.
The refrigeration cycle involves four main components: compressor, condenser, expansion valve, and evaporator. The condenser and evaporator function as heat exchangers, with heat being rejected in the condenser and absorbed in the evaporator. The compressor facilitates the refrigerant's movement through the cycle, and the expansion valve reduces the refrigerant's pressure and temperature after it leaves the compressor. Understanding this cycle is fundamental for anyone interested in HVAC systems.