PU sandwich panel production line refrigeration equipment refers to the equipment mainly used for crew food refrigeration, various cargo refrigeration 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 injection refrigeration equipment, heat pump refrigeration equipment and electrothermal refrigeration equipment. At present, compression refrigeration equipment is widely used on ships. The heat of the object and its surroundings is removed through the working cycle of the equipment, resulting in and maintaining a certain low temperature state. The currently used refrigerants are mainly Freon and ammonia, especially Freon. However, due to the damaging 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 reused and trial-produced.
The cooling methods of the refrigeration equipment of the polyurethane sandwich panel production line include direct cooling and indirect cooling.
Direct cooling is to install the evaporator of the refrigerator in the box or building of the refrigeration device, use the evaporation of the refrigerant to directly cool the air in it, and cool the objects to be cooled by the cold air. The advantages of this cooling method are 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, thereby cooling the carrier refrigerant (such as brine), and then feeding the carrier refrigerant into the box or building of the refrigeration device, and cooling the air in it through a heat exchanger. This cooling method has a slow cooling rate, a large total heat transfer temperature difference, and a complex system, so it is only used in less occasions, such as brine ice making and cold storage with constant temperature requirements.