Refrigerant system - Starget

3 ways to understand the refrigerant system

The refrigerant system also called the refrigerant circulation system, transfers heat from a substance (or environment) with a lower temperature to a substance (or environment) with a higher temperature by using external energy.
There are many types of refrigerant cycle systems, which can be divided into Freon refrigerant cycle systems, ammonia refrigerant cycle systems, mixed refrigerant cycle systems, and air and other refrigerant cycle systems according to the type of refrigerant used.


According to different working principles, it can be divided into compression type, absorption type, steam injection type, thermoelectric type, adsorption type and other refrigerant systems; among them, the compression type refrigerant cycle system is also called vapour compression type refrigerant cycle system, because of this system has good performance and high efficiency and has become the most widely used refrigerant circulation system.

A complete vapour compression refrigerant system should include the following:

  • A refrigerant circulation system.
  • Lubricating oil circulation system.
  • Defrosting system.
  • Cooling water circulation system.
  • Brine circulation system.

Among them, the vapour compression refrigerant circulation system comprises four basic parts: a refrigeration compressor, a condenser, a throttle valve, and an evaporator. The system includes auxiliary equipment, instruments, control devices, valves, pipes, etc., to ensure the refrigerant circulation system’s safety, reliability, economy and operation convenience.


In a nutshell, a refrigerant cycle system consists of two main parts. One part refers to the part of the cycle where the refrigerant leaves the throttle valve, enters the evaporator, and then reaches the suction valve of the compressor through the suction pipe. The pressure of the refrigerant in this part of the pipeline and equipment is close to the evaporation pressure, called a low-pressure system.

Refrigerant System Effect

Its function is to deliver low-temperature refrigerant liquid to the evaporator and evaporate the heat of the surrounding environment in the evaporator. In the cold storage refrigerant cycle system, most of the equipment and pipelines of the low-pressure system are placed in the warehouse, often called the warehouse system. The other part refers to the part of the cycle where the refrigerant reaches the throttle valve from the exhaust valve of the compressor through the exhaust pipe, oil separator, condenser, drain pipe, liquid reservoir, and high-pressure infusion pipe. The refrigerant pressure in this part of the pipes and equipment is close to the condensing pressure, called a high-pressure system.

The function of the high-pressure system is to increase the vapour pressure of the refrigerant, condense the vapour into a liquid through heat release, and restore its ability to evaporate and absorb heat from the cooling object. In the high-pressure system, the refrigerant releases heat to the surrounding environment. In the refrigerant circulation system of the refrigerator, most of the pipes and equipment of the high-pressure system are placed in the machine room or outside, also called the machine room system. This chapter takes the ammonia refrigerant circulation system as an example to explain its composition and working principle in detail.

Refrigerant is the working medium of the refrigerant system, so the quality of the refrigerant is very important. How to judge refrigerant quality can refer to the article How to detect refrigerant quality.

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