What is the purpose of a purge unit in a chiller system?

The purpose of a purge unit in a chiller system is to remove non-condensable gases, such as air and nitrogen, from the refrigerant. Non-condensable gases can enter the chiller system through leaks or during maintenance. These gases accumulate in the condenser, reducing its heat transfer efficiency and increasing the condensing pressure. The increased condensing pressure requires the compressor to work harder, increasing energy consumption and reducing the chiller's cooling capacity. Non-condensables can also cause corrosion and other problems in the system. The purge unit is designed to automatically extract these non-condensable gases from the system and vent them to the atmosphere or a recovery system, while minimizing the loss of refrigerant. The purge unit typically operates by drawing a sample of gas from the condenser and passing it through a separation chamber. The refrigerant is condensed and returned to the system, while the non-condensable gases are vented. For example, if air leaks into a chiller system, it will accumulate in the condenser. The purge unit will automatically detect the presence of air and remove it from the system, maintaining optimal condenser performance and preventing increased energy consumption. The operation of a purge unit is critical for ensuring the efficient and reliable operation of chiller systems.