The four main components of the refrigeration system: refrigeration compressor,Single fan air cooled condenser, throttling device (expansion valve or capillary tube, etc.),Air cooler for cold storage. The four main components and refrigerant have become necessary conditions for the realization of the refrigeration cycle.

(1) Compressors: generally used are piston type, screw type, scroll type, centrifugal type, rolling rotor type and so on.
(2)condenser: It mainly cools and condenses the superheated steam discharged from the compressor into a high-pressure liquid.
tube condenser:The refrigerant vapor is condensed outside the inner tube of the shell, and the cooling water in the tube is generally a bottom-in and top-out type of cooling water. The heat transfer coefficient is high, the condensation effect is good, and it is often equipped with water pumps and cooling towers.

Single fan air cooled condenser: Use air as the cooling medium and use a fan to accelerate the flow of air. It is suitable for places where water supply is difficult or inconvenient to install equipment such as cooling water towers, and the condensation effect is slightly poor.

(3) Throttle device: the main function of throttling and pressure reduction, to ensure the pressure difference between the condenser and the evaporator, so that the refrigerant evaporates and absorbs heat at low pressure (low temperature) in the evaporator; adjusts the refrigerant to adapt to changes in the evaporator's thermal load flow.

(4) Evaporator: The liquid refrigerant after throttling vaporizes and absorbs heat (low temperature and low pressure) in the evaporator to reduce the temperature of the cooled medium.

Drain pipe: simple structure, easy to make, low heat transfer coefficient, difficult to return oil.
Air cooler for cold storage:generally non-full liquid type, with less liquid filling, Air cooler for cold storage is good for oil return, less cold loss, and fast cooling.

Horizontal shell and tube evaporator: generally a dry shell and tube evaporator with high heat transfer coefficient, but difficult to return oil. Commonly used on chillers.