Refrigeration is the process of cooling a product or space to a temperature below that of its surroundings. It is used primarily for the preservation of perishable food products and for air conditioning to provide thermal comfort to human beings. The aim of refrigeration is to achieve and maintain a specific temperature, which can be achieved using different technologies and designs. The subject of refrigeration and air conditioning has a long history dating back centuries, and its evolution is closely tied to human needs for food and comfort. The book entitled “Refrigeration System” examines the different technologies and developments in refrigeration systems, including their design and implementation.