A refrigeration system in  which a compressor needs to provide cooling to several warehouses with different temperature  requirements at the same time is called a cold storage refrigeration system with one machine.

According to refrigeration requirements, it is always desired that the high-temperature storage has a higher evaporation pressure, and the low-temperature storage has a lower evaporation pressure. But in fact, the suction pressure of the compressor is always determined by the low-temperature storage. In order to obtain a higher evaporation pressure in the high-temperature storage room to obtain a higher and constant evaporation temperature, an evaporation pressure regulating valve is installed in the return gas pipeline of the high-temperature storage room. This keeps the pressure constant within a given range, and makes the refrigerant gas pressure after the valve consistent with the suction pressure of the compressor, which not only ensures the normal operation of each evaporator in the system under different working conditions, but also facilitates compression. The machine runs under a relatively stable suction pressure.