Basic Terms

Refrigeration system is a system that uses external energy to constantly remove and transfer the heat of low-temperature substances to other high-temperature substances.

Refrigeration system can be divided into vapour refrigeration system, air refrigeration system and thermoelectric refrigeration system. Vapour refrigeration system is the most widely used refrigeration system, it realizes refrigeration based on the theory that heat is absorbed when liquid vaporizes into steam.

And vapour refrigeration system can be divided into: (1) Vapour compression refrigeration system; (2) Vapour injection refrigeration system; (3) Vapour absorption refrigeration system.

Among these, vapour compression refrigeration system is mostly applied to common refrigeration equipments like cold storage, supermarket refrigeration equipment, refrigerated showcase, ice maker, ice cream equipment, industrial and commercial air conditioners and household refrigerators and freezers. So we hereby will focus on the introduction of vapour compression refrigeration system afterwards.

What Does Refrigeration System Consist of?

Vapour compression refrigeration system consists of four main mechanical parts : Compressor, Condenser, Expansion Vavle and Evaporator. Refrigerant is the agent to transfer the heat by circulating through the closed refrigeration cycle consisting of the four main parts connected by copper pipe.

Refrigeration Compressor

Compressor is the power of refrigeration cycle, it is driven by an electric motor and rotates constantly. Its function is to extract the low temperature and low pressure vapour in the evaporator in time and increase the pressure and temperature of refrigerant vapor by compression, so that the heat can be transferred to external environmental media lately.

Condenser

Condenser is a heat exchanger. The function is to use the environmental cooling medium (air or water) to take away the heat of the high temperature and high pressure refrigerant vapour coming from the compressor.

Expansion Valve

After taken the heat in the condenser, the refrigerant remains high pressure and can not be sent to evaporator directly. The function of expansion valve is to reduce the pressure of the refrigerant liquid, thereby reducing the temperature of the refrigerant liquid.

Evaporator

Evaporator is another heat exchanger with opposite function to the condenser, it absorbs the heat from external environment and reduce the external environment temperature and achieve the purpose of cooling, chilling and freezing.

How Does Vapor Compression Refrigeration Cycle Work?

The vapor compression refrigeration system is composed of four basic components: refrigeration compressor, condenser, expansion valve and evaporator. They are connected in turn by pipes to form a closed system. The refrigerant circulates continuously in the system and exchange heat with external environment with the vapour and liquid status changes and temperature change.

The low temperature liquid refrigerant in the evaporator absorbs the heat of external environment and vaporizes into low temperature and low pressure gas. It is then inhaled and compressed into high pressure and high temperature gas by the compressor and discharged into the condenser. And heat is released to the cooling medium (water or air) in the condenser. The refrigerant is condensed into normal temperature and high pressure liquid. And then then expansion vale reduces the pressure of the refrigerant and change the refrigerant status to low temperature and low pressure to be ready for the evaporator. It enters the evaporator again to absorb heat and vaporize to achieve the continuous cycle refrigeration. By this refrigeration cycle, the heat in an internal environment is transferred to the external environment and achieve the refrigeration purpose.