Refrigeration equipment refers to equipment mainly used for the refrigeration of crew food, refrigeration of all kinds of goods, and cabin air conditioning in summer. It is mainly composed of compressor, expansion valve, evaporator, condenser, accessories and pipelines. According to the working principle, it can be divided into compression refrigeration equipment, absorption refrigeration equipment, steam jet refrigeration equipment, heat pump refrigeration equipment and electric refrigeration equipment. The most common application on ships is compression refrigeration equipment. The work cycle of the equipment removes the heat from the object and its surroundings, causing and maintaining a certain low temperature state. The refrigerants used are mainly Freon and ammonia, especially Freon is the most used. However, due to the destructive effect of Freon on the atmospheric ozone layer, it has begun to be restricted by environmental protection regulations. Ammonia and other new refrigerants are being re-adopted and trial-produced.
There are two cooling methods for refrigeration equipment: direct cooling and indirect cooling. Direct cooling is to install the evaporator of the refrigerator in the box or building of the refrigeration device, and use the evaporation of the refrigerant to directly cool the air in it, and cool the object that needs to be cooled by the cold air. The advantage of this cooling method is that the cooling speed is fast, the heat transfer temperature difference is small, and the system is relatively simple, so it is widely used. Indirect cooling relies on the evaporation of the refrigerant in the evaporator of the refrigerator, so that the refrigerant (such as brine) is cooled, and then the refrigerant is input into the cabinet or building of the refrigeration device, and the air in it is cooled by a heat exchanger. This cooling method has a slow cooling speed, a large total heat transfer temperature difference, and a more complicated system, so it is only used in fewer occasions, such as salt water ice making and cold storage with constant temperature requirements.
According to different cooling purposes and cold utilization methods, refrigeration equipment can be roughly divided into four categories: refrigeration equipment for refrigeration, refrigeration equipment for testing, refrigeration equipment for production, and refrigeration equipment for air conditioning.
Refrigeration equipment for refrigeration is mainly used to store or transport food and other goods under low temperature conditions, including various refrigerators, cold storages, refrigerated trucks, refrigerated ships, and refrigerated containers.