What is the function of a reversing valve in a heat pump system?

The function of a reversing valve in a heat pump system is to direct refrigerant flow. This critical component allows the heat pump to change the direction of the refrigerant, enabling the system to either heat or cool the indoor environment. When the heat pump is in heating mode, the reversing valve directs the refrigerant to absorb heat from the outside air and transfer it indoors. Conversely, in cooling mode, the valve reverses the flow so that the refrigerant removes heat from indoors and releases it outside. It acts as the pivotal part of the system that determines the operational mode, making it essential for the heat pump's functionality.

Other options like controlling airflow, regulating temperature, and increasing energy efficiency, while important in the overall operation of HVAC systems, do not directly relate to the specific role of the reversing valve. That valve's primary task is specifically about steering the path of the refrigerant to achieve the desired thermal effect in the building.