What is the primary action taken during hot gas defrost in a refrigeration system?

During hot gas defrost in a refrigeration system, the primary action involves piping high-pressure gas from the discharge of the compressor through the evaporator. This process is designed to alleviate ice buildup on the evaporator coils, which can occur when moisture in the air freezes during the cooling cycle.

When the high-pressure gas is directed into the evaporator, it releases heat, effectively melting the accumulated ice or frost. This method of defrosting is efficient because it uses the existing refrigerant gas that is already heated due to the compression process. Instead of relying on external heating sources, hot gas defrost leverages the heat content of the refrigerant itself to quickly raise the temperature of the evaporator coils, facilitating a rapid thaw.

This action is crucial for maintaining system efficiency, as excessive ice buildup can impede the heat exchange process, leading to poorer cooling performance and increased energy consumption.