Refrigeration units are appliances designed to remove heat from a designated area, keeping it cool. They work by circulating a refrigerant through a closed system, absorbing heat from the inside and releasing it outside. Common types include refrigerators, freezers, and commercial refrigeration systems used in restaurants and grocery stores. These units are essential for preserving food, medicines, and other perishable items. They come in various sizes and designs, catering to different needs, from small household models to large industrial units. Proper maintenance ensures efficiency and longevity, making them vital in both residential and commercial settings.