What type of defrost control is commonly employed in heat pumps?

The commonly employed defrost control in heat pumps is time initiation and temperature termination. This method involves starting the defrost cycle based on a set time interval, allowing the system to regularly initiate defrosting to remove accumulated frost from the evaporator coil. The defrost cycle will then conclude once a specified temperature is reached, ensuring that the heat pump effectively returns to heating mode without excessive and unnecessary energy consumption.

Time initiation is beneficial because it ensures that defrost cycles occur regularly, preventing frost buildup that could impede heat transfer efficiency. On the other hand, temperature termination helps to avoid the risks of over-defrosting, where the heat pump could be unnecessarily taken out of operation, thus maintaining system efficiency and comfort levels.

While other methods exist, this combination effectively balances the need for regular defrosting with energy efficiency, making it a preferred choice in many heat pump applications.