“Monitoring and lessons-learned of an 800 kW sector-coupling heat pump from wastewater to district heating in Gleisdorf”
The use of wastewater as a local energy source is gaining relevance as part of broader efforts to decarbonize heating systems and transition toward more sustainable energy solutions. In this context, a large-scale heat pump system with a thermal capacity of 800 kWth was implemented at the wastewater treatment plant (WWTP) in Gleisdorf, Austria, to recover heat from wastewater and supply the district heating (DH) network via a newly built 1 km long DH pipeline. To assess the overall performance of the heat pump system, a comprehensive monitoring concept was developed and applied from the start of operation. Furthermore, a digital dashboard was implemented to intuitively monitor the measured data, as well as key performance indicators, and identify challenges during operation. This approach aimed to evaluate the success of implementation, build operational knowledge, and identify areas for improvement, recognizing that informed decision-making is only possible with high-quality data and long-term evaluation. During the one-year monitoring period, which was evaluated within the project "Fossilfree4Industry", the heat pump generated a total of 3,780 MWh of thermal energy to the buffer tank and 3,500 MWh were fed into the DH network with an average feed temperature of 79°C. This is close to the design target of 4,320 MWh/year. The planning benchmark for the seasonal performance factor (SPF) was 2.65, estimated by averaging monthly calculated coefficients of performance (COP). This benchmark was closely approached by the implemented system, which achieved a SPF of 2.58 over the monitoring period. In conclusion, the heat pump integration demonstrates stable and efficient performance under real operating conditions.