Freezer evaporator with heater

A freezer evaporator with a heater is a component commonly found in frost-free or automatic defrost freezers. The primary purpose of the heater in the evaporator is to prevent the buildup of ice on the freezer evaporator coils, ensuring efficient operation and maintaining a consistent temperature within the freezer. Here's how it typically works:

1. Evaporator Coils:

   • The freezer evaporator is a heat exchange component located inside the freezer. It consists of coils through which a refrigerant circulates. As the refrigerant evaporates, it absorbs heat from the freezer's interior, cooling the air.

2. Automatic Defrost System:

   • Freezers with an automatic defrost system are designed to periodically melt any ice or frost that accumulates on the evaporator coils. This prevents excessive ice buildup, which could reduce the freezer's efficiency over time.

3. Defrost Heater:

   • The defrost heater is a heating element placed in or around the freezer evaporator coils. It is typically activated during the defrost cycle. When the freezer's temperature control system detects that frost or ice has built up on the evaporator coils, it initiates the defrost cycle.

4. Defrost Timer or Control Board:

   • The defrost cycle is controlled by either a mechanical defrost timer or an electronic control board. The timer or control board determines when to activate the defrost heater.

5. Heating and Melting Ice:

   • When the defrost cycle is initiated, the defrost heater heats up, causing the ice on the freezer evaporator coils to melt. The resulting water is then drained away from the coils.

6. Drain System:

   • The melted water flows into a drain pan or through a drain tube and is eventually directed to a collection pan located near the compressor at the back of the freezer. Some freezers use a drain pan, while others use a heated drain tube to prevent clogging.

7. Resuming Cooling:

   • After the defrost cycle is complete, the defrost heater is turned off, and the freezer returns to its normal cooling mode. The water collected during the defrost cycle evaporates or is removed from the freezer through the drainage system.

By incorporating a heater in the freezer evaporator, frost-free freezers eliminate the need for manual defrosting, providing convenience to users and maintaining optimal freezer performance. This is particularly important for keeping food items at a consistently low temperature without the hindrance of frost buildup.