Air-source heat pumps can also be combined with a ventilation system. These draw their energy from the exhaust air of the interior of a building via the central ventilation system. This means that this system can fall back on constantly high temperatures, so that the efficiency is relatively high compared to heat pumps with outside air intake. However, the pure COP values that provide information about this are not comparable with other ventilation systems due to the combination of the devices.
The extraction capacity is limited due to the defined air volume. This technology is therefore only suitable for buildings that require very little heating energy compared to the available exhaust air volume, i.e. especially for passive houses. The energy generated is fed into rooms to be heated again via the ventilation system. This also limits the possible input of heating energy. To support the system, the systems contain a heat exchanger that is connected in front of the heat pump and already takes over a proportionate heat transfer without the use of electrical energy. As with a classic ventilation system, an external geothermal heat exchanger has a positive effect, which preheats the fresh air in cold weather and pre-cools it in summer.
1: Heat pump ventilation unit
2: Buffer tank
3: Outside air intake
4: Exhaust air duct
5: Supply air
6: Exhaust air
Source: bauwion
