What is the intended effect of using hot gas for defrosting?

Using hot gas for defrosting primarily serves to melt ice or frost buildup in the evaporator. In refrigeration systems, ice or frost can accumulate on the evaporator coils, which impairs heat exchange and can reduce the system's efficiency. By introducing hot gas, the temperature of the evaporator coils is increased, causing the ice or frost to melt. This process restores efficient heat transfer and allows the refrigeration cycle to operate effectively once again.

The other options do not accurately describe the action of hot gas in defrosting. The aim is specifically to address the buildup of frost rather than cooling down the evaporator, maintaining low temperatures, or directly increasing compressor efficiency.