Why do chillers using CFC-11 and HCFC-123 require purge units?

Chillers that use CFC-11 and HCFC-123 require purge units primarily because these systems often operate under conditions where the refrigerant can become contaminated with non-condensables, such as air or moisture, that enter the system. One significant aspect of these chillers is that they operate below atmospheric pressure, making them susceptible to the ingress of these non-condensables.

When the system operates at sub-atmospheric pressure, it may draw in air and moisture, which can significantly impact the efficiency and safety of the system. The purge unit serves to remove these unwanted gases to help maintain the proper functioning of the chiller. By keeping the refrigerant levels clear of non-condensables, the purge unit helps prevent operational issues that can arise from pressure imbalances or inefficiencies, making it a crucial component in the maintenance of such chillers.

This understanding highlights the importance of proper design and maintenance in refrigeration systems, particularly those using refrigerants like CFC-11 and HCFC-123.