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 refrigerants can result in the accumulation of non-condensable gases within the system. Over time, the operation of these chillers can lead to the aspiration of air into the refrigeration circuit, especially at lower pressures. Since these chillers often operate below atmospheric pressure, any leakage or diffusion from the environment can introduce air, which lowers the system's efficiency and increases energy consumption.

The purge units are designed to remove these non-condensable gases from the refrigeration system, thereby maintaining optimal performance and preventing potential operational issues like reduced cooling capacity and increased compressor wear. By ensuring that only refrigerant is present in the system, the purge unit plays a critical role in maintaining the integrity and efficiency of the chiller operation.