Refrigeration principle

Update:11 Jan 2020
Summary:

The single-stage steam compression refrigeration system […]

The single-stage steam compression refrigeration system is composed of four basic parts: refrigeration compressor, condenser, throttle valve and evaporator. They are connected by pipes in turn to form a closed system, in which the refrigerant circulates continuously, changes state and exchanges heat with the outside world.
After the liquid refrigerant absorbs the heat of the cooled object in the evaporator, it vaporizes into low-temperature and low-pressure steam, is sucked in by the compressor, compressed into high-pressure and high-temperature steam, and then it is discharged into the condenser. In the condenser, it releases heat to the cooling medium (water or air), condenses into high-pressure liquid, throttles into low-pressure and low-temperature refrigerant through the throttle valve, and enters the evaporator again to absorb heat and vaporize, so as to achieve circulation Purpose of refrigeration. In this way, the refrigerant in the system through compression, condensation, throttling, evaporation four basic processes to complete a refrigeration cycle.
In the refrigeration system, the evaporator, condenser, compressor and throttle valve are the four essential parts of the refrigeration system, in which the evaporator is the equipment to deliver the cooling capacity. The refrigerant absorbs the heat of the cooled object in it to realize refrigeration. The compressor is the heart, which takes in, compresses and transports refrigerant vapor. The condenser is a device to release heat, which transfers the heat absorbed by the evaporator to the cooling medium together with the heat converted by the work done by the compressor. The throttle valve can throttle and depressurize the refrigerant, control and regulate the amount of refrigerant liquid flowing into the evaporator at the same time, and divide the system into high pressure side and low pressure side. In the actual refrigeration system, in addition to the above four parts, there are often some auxiliary equipment, such as solenoid valve, distributor, dryer, collector, fusible plug, pressure controller and other components, which are set to improve the economy, reliability and safety of operation.