Heating and cooling with energy from wastewater are possible in any building with a power requirement of around 50 kW or more. That is around 15 residential units. The largest system constructed to date has a heat extraction rate of 2.1 MW and supplies a district with over 450 residential units plus commercial users. Commercial buildings are also easily heated and cooled using wastewater energy. The aim is that energy from wastewater will reach a temperature of 35 to 55 °C using heat pump technology. However, there are now also many projects when energy is stored at a higher temperature. It is always a question of competition and the next best option. Wastewater heat is also particularly suitable for storage in local authority or municipal heat networks. These local and district heating networks can be both cold and hot networks.
