How can heat be extracted from drinking water to heat buildings? A research team from the Faculty of Supply Engineering at Ostfalia University of Applied Sciences is working on this question in collaboration with various partners. “Germany aims to become climate-neutral by 2045. This also applies to building heating systems. Traditional gas and oil heating systems are to be gradually replaced by heat pumps. However, in densely built-up city centres in particular, there is often a lack of space for geothermal probes or other renewable heat sources,” says Prof. Dr Lars Kühl, explaining the current situation.
This is precisely where the project ‘Heat from Drinking Water – Safe and Feasible: WaTsup’ comes in. It was developed by Prof. Dr.-Ing. Jens Wagner and Prof. Dr.-Ing. Lars Kühl. They are supported in this by two research assistants. The project partners in this collaborative initiative are the IWW Institut für Wasserforschung gemeinnützige GmbH from Mühlheim an der Ruhr, which is also responsible for overall project management, Avacon Wasser GmbH from Wolfenbüttel, and swb Service GmbH from Bremen. In addition to their respective expertise, a further twelve companies from the utilities sector will support the project as associated project partners.
Ostfalia project leader Prof. Dr Jens Wagner sees this as a promising, innovative approach to the heat transition.
“Drinking water networks and storage facilities could be used as a heat source in future. The piped network is already in place across the board and maintains a consistent, usable temperature throughout the year. In combination with heat pumps, this could reliably and sustainably meet part of the inner-city heating demand,” explains Wagner. The Ostfalia researcher sees a further advantage in the fact that extracting heat from the water mains network could actively counteract the rise in water temperatures caused by climate change. “So far, however, there are hardly any practical examples of this approach in Germany, mainly due to unresolved technical issues and a lack of approval procedures,” says Wagner.
The project is therefore investigating the technical potential in the model regions of Bremen and Lüneburg. Tests will be carried out at two existing plants and a new pilot plant to determine how heat recovery can be implemented safely and to the highest hygiene standards.
The findings will then be incorporated into practical guidelines for operators, taking into account technical, organisational, energy-related and economic aspects. In addition, clear recommendations will be formulated for the necessary adaptation of the legal framework.
The research project is funded by the Federal Ministry for Economic Affairs and Energy (BMWE) with approximately 620,000 euros from the 8th Energy Research Programme and will run for three years (until around summer 2029).
