A Project 61 expert meeting was held at the Institute of Thermal Engineering and Thermodynamics at the Technical University Bergakademie Freiberg TUBAF on Nov. 27-28, 2025. The meeting was attended by representatives of Austria, Germany, Italy and Switzerland on-site and the USA and Japan online.
Simulation and monitoring results have been discussed on the contribution of the participating institution:
- Simulation and monitoring results on an asphalt collector in Vienna show cooling potentials and heat recovery for borehole regeneration in summer, but has also faced control problems in the monitoring period.
- Results on two larger districts in Austria and Switzerland confirm high heat pump performance, but also the high ambition to reach a Positive Energy District on the balance boundary of the building footprint.
- A retrofit concepts in Germany focuses on deep envelope renovation, which shall be refunded by high energy performance of a heat pump and PV combination as well as tenant electricity and smart control.
- Another German contribution has simulated and monitored the use of mine water as seasonal heat storage in Freiberg.
- Furthermore, data-driven methods for load profile derivation based on building measurements to characterize the load situation in districts has been developed and tested in Italy.
- Evaluations of the monitored DHW operation in blocks of flats and simulation results on DHW operation and integration was presented by Austria.
- The presentations were concluded by the presentation of a study on grid configurations of Germany, Austria and Switzerland and central and decentralised integration options of heat pumps.
Based on the discussion of results the structure of the final reporting has been reviewed.
Results shall be presented in reports and different case study sheets for simulated system concepts and monitored heat pumps in building clusters and districts. The final documents will be published on the Project 61 website after review of the HPT ExCo in the end of 2026.
The meeting also incorporated a visit to the Freiberg Christmas market and was concluded by a technical visit to the district cooling central of the Campus cooling system.