What type of heat pump absorbs heat from a building water loop and rejects it into air?

The type of heat pump that absorbs heat from a building water loop and rejects it into the air is indeed a water-to-air heat pump. This system operates by transferring heat from the water source that is typically within the building, such as a hydronic heating system or a chilled water loop.

In this process, the water loop acts as a heat source in the winter when the pump absorbs heat from it, raising the temperature and then transferring that heat to the air being circulated within the building. Conversely, during warmer months, the heat pump can also act in reverse, removing heat from the indoor air and rejecting it back into the water loop for cooling purposes.

This efficiency in heat transfer and the ability to utilize a water loop for both heating and cooling makes the water-to-air heat pump a practical and effective choice for climate control in buildings. Other systems listed, like ground-to-air or geothermal heat pumps, typically rely on the earth as a thermal reservoir rather than a building water loop, while air-to-water systems are designed to extract heat from the air and transfer it to water, not the other way around.