What is the purpose of a defrost cycle in refrigeration?

The purpose of a defrost cycle in refrigeration is primarily to remove frost buildup from the evaporator. When moisture from the air enters the evaporator coil, it can freeze and form frost. This frost accumulation can insulate the coil, significantly decreasing its ability to absorb heat and, consequently, reducing the cooling efficiency of the system. The defrost cycle is designed to periodically raise the temperature of the coil to melt this frost, allowing for proper heat exchange to resume.

Addressing the other options: While increasing cooling efficiency is a result of effectively managing frost buildup, the defrost cycle itself directly targets the removal of frost. Maintaining refrigerant levels is not related to the defrost process; instead, refrigerant management is about ensuring the system operates within its designed parameters. Proper airflow can be impacted by frost buildup but is not the main intent of a defrost cycle, which specifically focuses on thawing the evaporator coil.