In the research project "Innovative waste heat utilisation through heat distribution via the canal system - InnoA2" funded by the Federal Ministry of Economics and Energy (BMWI) at the Technical University of Kaiserslautern in cooperation with the Fraunhofer Institute for Systems and Innovation Research (ISI) and the Stadtbetrieb Abwasserbeseitigung Lünen AöR (SAL), an fresh approach to waste heat utilisation is being investigated. In the first phase of the project, the fundamental feasibility of this innovative approach in the urban area of Lünen could already be demonstrated.
The innovative waste water heat utilisation approach (InnoA2 approach) contains the idea, that the decentralised waste heat generated in trade/industry is added to the existing waste water stream and that a moderate increase in the waste water temperature by approx. 10-15 K is generated. The heat energy transferred in this way is transported in the waste water stream with low losses in the direction of flow and removed downstream using established techniques such as heat exchangers and heat pumps.
In comparison to alternative heat sources (e.g. geothermal energy and air), the specifically heated wastewater offers a heat source that is available all year round and at a higher temperature. The existing waste water volume flow is not changed quantitatively. Only the temperature of the waste water is specifically increased. The technical and legal concerns expressed in the course of the research project were completely dispelled.
Within the framework of this research project, a web-based calculation tool was developed at the Department of construction engineering of the TU Kaiserslautern. This tool takes into account both, the conventional use of waste water heat and the innovative use of waste water heat and compares the corresponding estimates. The aim is to provide local authorities with a user-friendly tool for an initial assessment of the local potential for wastewater heat utilisation.