What happens during hot gas defrost?

During hot gas defrost, high pressure gas from the compressor discharge is piped through the evaporator. This process is designed to remove the frost or ice buildup on the evaporator coils. By introducing hot gas directly into the evaporator, the coils heat up, causing the ice to melt and ensuring that the coils can operate efficiently and maintain their designed heat transfer capabilities.

This method allows the system to recover quickly from frost accumulation, facilitating an efficient and effective return to normal operational conditions without requiring the unit to turn off. It's particularly useful in refrigeration systems where maintaining a consistent temperature is crucial, and it can be executed without significant interruption to the refrigeration cycle.

The other options do not accurately describe the hot gas defrost process. For example, introducing a brine solution over the coils or requiring all units to defrost simultaneously are not characteristics of this method, nor does oil accumulation directly tie into the definition or execution of hot gas defrost.