GCAP Book Practice Test

During a hot gas defrost cycle, high-pressure gas from the compressor discharge is piped through the evaporator to remove ice or frost buildup. This method is effective in melting the frost that has accumulated on the evaporator coils, ensuring that the system can effectively transfer heat and maintain efficient operation.

In this process, the refrigerant is in a gaseous state and is at high pressure and temperature. When this hot gas circulates through the evaporator, it raises the temperature of the coils enough to melt the ice, which allows for proper heat exchange. The hot gas effectively transfers heat back into the evaporator, reversing the regular cooling process temporarily to clear any frost that has formed.

The other options do not correctly describe the hot gas defrost cycle. The mention of circulating cold gas through the evaporator would not accomplish the goal of melting frost, while liquid refrigerant injection occurs in different contexts. Absorbing heat from the surrounding environment is also not part of a defrost cycle, as the purpose of the cycle is to remove frost, not absorb additional heat.