What is the purpose of crankcase heaters in reciprocating chillers?

The purpose of crankcase heaters in reciprocating chillers is primarily to prevent refrigerant migration to the crankcase. Reciprocating chillers use refrigerants that can migrate to the crankcase when the unit is off, especially in cooling applications where the temperature difference can encourage this process. When refrigerant collects in the crankcase, it can lead to liquid refrigerant being present during startup, which may cause compressor damage or operational inefficiencies.

By employing crankcase heaters, the temperature of the crankcase is maintained above the saturation temperature of the refrigerant, thus preventing its migration and ensuring that the compressor starts with only vapor, enhancing reliability and longevity of the compressor's operation. This maintenance of the crankcase temperature is essential for protecting the compressor and ensuring that the chiller functions effectively when it is restarted after being off.