HVAC - Common Auxiliary Components of the Refrigeration System

Oil Separator:
In the Freon refrigeration system, the refrigeration oil will enter the evaporator together with the refrigerant. Since the temperature of the evaporator is low, the refrigeration oil is likely to accumulate in the evaporator, which affects the heat exchange of the evaporator. Moreover, the presence of oil in the evaporator will cause the compressor to be short of oil and more likely to be damaged. In order not to affect the heat exchange and to reduce the amount of oil entering the evaporator, an oil separator is installed in the exhaust pipeline of the compressor in the refrigeration system.

It can separate most of the oil that rushes out together with the refrigerant, and the separated oil flows back to the compressor through the pipeline connecting the oil separator and the compressor.

Gas-Liquid Separator:
The function of the gas-liquid separator is to separate the mixed gaseous and liquid refrigerants returning from the evaporator. It is connected to the return pipe of the compressor to prevent the compressor from experiencing liquid hammer.

Liquid Receiver:
It is used to store the refrigerant liquid to adjust the circulation volume of the refrigerant when the refrigeration load changes, and to reduce the frequency of replenishing the refrigerant in the refrigeration system.

Dryer Filter:
It absorbs the moisture in the refrigeration system and blocks the impurities in the system to prevent them from passing through, thus preventing the pipelines of the refrigeration system from being blocked by ice and dirt.
The most easily blocked part of the system is the capillary tube (or expansion valve). Therefore, the dryer filter is usually installed between the condenser and the capillary tube (or expansion valve).

Suction Filter:
A suction filter is installed at the inlet of the compressor to prevent impurities from entering the compressor and causing compressor failure.

Safety Valve:
As an important valve component of the refrigeration system, it is used to ensure the safe operation of the refrigeration system at the set pressure. It is mostly installed on the high-pressure side of the refrigeration system, often on equipment such as condensers or liquid receivers to avoid excessive pressure in the container. In some small refrigeration systems, a fusible plug can be set to replace it.

Solenoid Valve:
The solenoid valve is an executive element for the automatic control of the refrigeration system. It uses the electromagnetic principle to control the flow of gaseous or liquid refrigerants in the pipeline by turning the power supply on and off. When the coil is energized, a magnetic field is generated, the iron core is attracted and moves in the direction of the arrow, and the valve opens; when the power is cut off, the valve core returns to its original position by its own weight or the spring force, and the valve closes.

Pressure Controller:
The pressure controller is widely used in various refrigeration equipment. It controls the pressure through the opening and closing of the contacts. Common types include high-pressure pressure controllers, low-pressure pressure controllers, oil pressure controllers, etc.
The high-pressure pressure controller is used to control the high-pressure or exhaust pressure. When the air volume of the air-cooled condenser is insufficient or there is no air supply, the water volume of the water-cooled condenser is insufficient or the water temperature is too high, or even when there is no water supply, or for other reasons that cause the high-pressure to exceed the set value of the pressure controller, the controller trips and disconnects the circuit of the contactor, making the compressor stop to protect the system.

Sight Glass:
The sight glass can detect the water vapor present in the refrigerant, and it is usually installed at the rear end of the dryer filter. The color indicator in the sight glass can show the water vapor content. Green indicates that there is no dangerous water vapor in the refrigerant. Yellow indicates that the water vapor content in the liquid pipeline at the front end of the expansion valve is too high.

Evaporator Pressure Regulator:
The function of the pressure regulator is to control the pressure level of the system, enabling the system to work more effectively under various conditions. The main function of the evaporator pressure regulator is to keep the pressure inside the evaporator constant; therefore, it will open and close according to the load condition of the evaporator.

Economizer:
The economizer is a heat exchanger. Through the throttling and evaporation of the refrigerant itself to absorb heat, another part of the refrigerant can be subcooled.
The economizer is often used in the refrigeration system of the two-stage inlet compressor. Under the working condition of a relatively low evaporation temperature (below -25°C), the efficiency of the compressor decreases, the refrigeration capacity decreases, and the exhaust temperature is relatively high. Using the economizer gas injection cycle can improve the efficiency of the compression refrigeration cycle, increase the refrigeration capacity, and reduce the exhaust temperature of the compressor. The use of the economizer can make the single-stage screw compressor have a wider application range and be more economical.

Ball Valve and Angle Valve:
As the name implies, the spool of a ball valve is in the shape of a ball, and the refrigerant flows out through the round hole in the middle of the ball.

The reason why the angle valve is called an angle valve is that the refrigerant entering and leaving it is at a 90-degree angle and perpendicular to each other, unlike the ball valve which has a straight-in and straight-out flow. The angle valve plays the role of blocking the medium and facilitating the maintenance of terminal equipment.