The key components of a refrigeration system include the compressor, condenser, expansion valve, and evaporator. The compressor compresses the refrigerant, which then flows to the condenser, where it releases heat to the surrounding air or water. The refrigerant then passes through the expansion valve, which reduces its pressure and allows it to expand, and finally to the evaporator, where it absorbs heat from the cooled space or product. These components work together to maintain the refrigeration cycle, and each component’s performance affects the overall system efficiency and reliability.