Basics

Vapor-compression refrigeration is the most widely used method for air conditioning buildings and vehicles, and is also employed in domestic and commercial refrigerators. This system works by circulating a liquid refrigerant that absorbs and removes heat from a space, undergoing phase changes to transfer the heat elsewhere. A typical VCRS consists of a compressor, condenser, expansion valve, and evaporator. The refrigerant enters the compressor as a saturated vapor, is compressed and heated, then condenses in the condenser by releasing heat to an external medium. The resulting saturated liquid refrigerant undergoes pressure reduction in the expansion valve, cooling down before entering the evaporator. Here, it absorbs heat from the air, evaporates, and returns to the compressor to complete the cycle.