What is the function of an electric defrost heater in refrigeration?

The function of an electric defrost heater in refrigeration systems is primarily to melt frost build-up on evaporator coils. When refrigeration systems operate, especially in colder temperatures or in humid conditions, frost can accumulate on the evaporator coils. This frost acts as an insulating layer that can hinder the efficiency of heat exchange, reducing the overall performance of the refrigeration system.

By using an electric defrost heater, the frost is melted, allowing for the coils to operate effectively. This process is crucial, as it ensures that the evaporator can absorb heat properly, maintaining optimal refrigerator performance and preventing issues such as decreased cooling efficiency or even system failure due to excessive frost build-up.

The other options relate to different functions within the refrigeration cycle, but they do not specifically pertain to the role of an electric defrost heater. Maintaining refrigerant pressure, assisting in refrigerant evaporation, and increasing compressor efficiency are all important aspects of refrigeration, but they do not involve the defrosting process that the electric defrost heater is designed to address.