The function of the condenser is to release heat to the atmosphere through the metal tube wall and fins of the high temperature and high pressure refrigerant discharged from the compressor, so that the high temperature and high pressure gaseous refrigerant can be condensed into medium temperature and high pressure liquid refrigerant. The refrigerant in gas state is liquefied or condensed in the condenser. When the refrigerant enters the condenser, it is almost 100% steam. When it leaves the condenser, it is not 100% liquid, because only a certain amount of heat energy is discharged by the condenser in a given time. Therefore, a small amount of refrigerant leaves the condenser in a gas state, but since the next step is the receiver dryer, this state of refrigerant does not affect the operation of the system.
The receiver dryer is mainly composed of receiver, desiccant and filter. Its function is to store refrigerants, filter moisture and impurities, and prevent gaseous refrigerants from entering the evaporator. The receiver dryer provides a buffer space for the liquid refrigerant in the system, which can timely adjust and supplement the flow of liquid refrigerant supplied to the thermostatic expansion valve to ensure the continuity and stability of the refrigerant flow in the system.
A glass liquid sight glass is installed at the upper outlet end of some receiver dryers to observe the flow state of refrigerant during operation, so as to judge whether the refrigeration dosage is appropriate. Some models have a pressure switch on the receiver dryer, which can stop the compressor when the system pressure is abnormal. Some receiver dryers are equipped with service valves for the installation of pressure gauges and filling of refrigerants during the maintenance of the refrigeration system.
Due to different expansion and throttling devices, the installation position of the receiver dryer is also different. Generally speaking, in the refrigeration system equipped with expansion valve, a receiver dryer is set at the rear of the condenser outlet, and the refrigerant from the receiver dryer is already a liquid refrigerant with a certain degree of cooling; in the refrigeration system equipped with throttle tube, the receiver dryer is installed on the low-pressure pipe of the air conditioner compressor, which is also called the liquid collector, which can prevent the liquid refrigerant from being Direct suction air conditioning compressor.
The sight glass is also known as the observation window. Its function is to observe whether the refrigerant filling amount is in place when filling the refrigerant. It is also used to judge whether the cooling capacity of the air conditioning system is insufficient and whether the refrigerant is reduced due to the refrigerant leakage. In many automotive air conditioning systems, the sight glass is mostly installed on the receiver dryer, which has the advantages of compact structure and high reliability. However, in some cases, if it is inconvenient or impossible to observe the refrigerant on the receiver dryer when filling the refrigerant, the sight glass is installed on the high-pressure pipeline system; in addition, when using the CCOT system, because the sight glass cannot be installed on the gas-liquid separator, the sight glass needs to be installed on the high-pressure pipeline system. The liquid collector is installed in the low-pressure area of the refrigeration system, while the receiver dryer is installed in the high-pressure area of the system.
The liquid refrigerants are stored in the collector and the receiver dryer, but these refrigerants stored in the collector will evaporate naturally in the low-pressure area slowly, and only the gaseous refrigerants leave the collector, thus playing the role of gas-liquid separation. The redundant liquid refrigerant left by the receiver dryer is used to adjust the operation requirements. The main part of the liquid collector is gas, so the volume is required to be larger, so the size of the liquid collector is generally larger, while the size of the receiver dryer is generally smaller.