What component allows an AC Heat Pump to reverse refrigerant flow for seasonal use?

The component that allows an AC heat pump to reverse refrigerant flow for seasonal use is the reversing valve. This critical part enables the heat pump to switch between heating and cooling modes.

In heating mode, the reversing valve allows refrigerant to flow in a way that absorbs heat from the outside air (even when it's cold) and transfers it indoors. Conversely, in cooling mode, the reversing valve changes the flow so that the heat absorbed from inside the building is released outside. This ability to reverse the refrigerant flow is what makes heat pumps versatile for both heating and cooling applications.

Other components mentioned in the choices contribute to the system's overall function but do not have the capability to change the direction of refrigerant flow. The condenser and compressor play roles in moving and condensing the refrigerant, while the expansion valve is responsible for regulating the flow of refrigerant into the evaporator coil, but none of these components can switch the refrigerant's direction as the reversing valve does.