Beijing Chigo Air Conditioning After-sales Service Center edited and organized on September 23, 2011.
The function of the throttle valve is to throttle and reduce the pressure of the high-pressure liquid refrigerant flowing out of the condenser, allowing it to vaporize and absorb heat under low pressure. Additionally, the throttle valve in an air conditioner also has the role of regulating the refrigerant flow rate according to the load and controlling the cooling effect.
So, what types of throttling devices are there in air conditioners? For air conditioners of different specifications, the size of their cooling capacity also varies, requiring the use of different types of throttling devices. The throttling device in an air conditioner comes in two types: capillary tubes and expansion valves. Expansion valves further come in two kinds: thermal expansion valves and electronic expansion valves. Small air conditioners, due to their smaller cooling capacity, generally use capillary tubes as throttling devices. Large air conditioners, because of their larger cooling capacity, typically use expansion valves as throttling devices. Among them, single-cooling small air conditioners only need one capillary tube, while heat pump air conditioners, due to different cooling and heating conditions, usually require two capillary tubes. The inner diameter of a capillary tube is generally between 0.1 to 1.6mm, and its length is between 500 to 1000mm. It has a simple structure, is easy to process, has a low cost, is less prone to failure, and can meet throttling requirements under conditions where room temperature changes little. Its disadvantage is poor regulation capability, unable to adjust the flow rate according to changes in the refrigeration system load; its advantage is that after the compressor stops, it easily maintains pressure balance between the low-pressure and high-pressure parts of the system, making it easier to start the compressor.
Chigo Air Conditioning Repair Q&A: The Function and Classification of Air Conditioning Throttle Devices