In heat pump systems, what does the reversing valve do?

In heat pump systems, the reversing valve plays a crucial role in determining the direction of the refrigerant flow. This is essential because a heat pump can operate in two modes: heating and cooling. When the system is in heating mode, the reversing valve directs the refrigerant flow so that it absorbs heat from the outside air (even in low temperatures) and releases it indoors. Conversely, in cooling mode, the valve changes the direction of the refrigerant to absorb heat from the indoor air and release it outside. This ability to reverse the flow enables the heat pump to provide both heating and cooling functions efficiently, making the reversing valve a key component of the system's versatility and functionality.

The other options don’t accurately describe the role of the reversing valve. Unlike a filter, which removes impurities from the refrigerant, the reversing valve does not perform filtration. It does not increase pressure either, as that is managed by the compressor, and while it indirectly supports controlling temperatures through the mode effect, it does not regulate thermostat settings itself. The primary and crucial function of the reversing valve is the change in refrigerant flow direction, enabling the heat pump's dual operation modes.