The defrost function in a refrigerator is designed to remove built-up frost and ice from the freezer compartment. Here's how it typically works:
Defrost Timer: The refrigerator has a defrost timer that activates the defrost cycle at regular intervals. The timer is usually located at the back of the refrigerator, near the compressor.
Heater Coil: When the defrost cycle begins, power is sent to a heater coil that is either wrapped around the evaporator coils or placed beneath them. The heater coil heats up, generating heat.
Heat Transfer: As the heater coil warms up, it raises the temperature of the evaporator coils. This heat causes the frost and ice to melt, turning it into water.
Drainage: The water resulting from the melted frost and ice typically flows down to a drainage pan located at the bottom of the refrigerator or freezer. Some models may have a drain tube or a small channel that directs the water into the pan.
Evaporation: The water in the drainage pan is usually shallow and exposed to warm air from the condenser coils or the compressor. This causes the water to evaporate over time.
Defrost Cycle Completion: The defrost timer keeps the heater coil activated for a set period, typically around 20-30 minutes. Once the defrost cycle is complete, the timer switches off the heater coil, ending the heating process.
Cooling Resumes: After the defrost cycle, the refrigerator returns to its normal cooling mode. The compressor and other cooling components start functioning again, while the evaporator coils cool down.
It's important to note that some modern refrigerators employ more advanced defrosting methods, such as adaptive defrost systems. These systems use sensors to detect frost build-up and initiate defrost cycles only when necessary, optimizing energy efficiency. Additionally, some refrigerators may also have a fan that circulates the heated air to speed up the defrosting process. The exact mechanism can vary depending on the specific refrigerator model.