The members of Annex 61 held several presentations on the national contribution at the Clima 2025 REHVA World Congress, which took place at the Polytecnico di Milano on 4.-6. June, 2025.
Lukas Oppelt of TU Bergakademie Freiberg presented a project with integration of seasonal water storage from abandoned and partially flooded mines in Saxony, Germany. A test storage system has been installed comprising a mobile heat pump test rig to store and extract heat cyclically in a basin of approx. 21 m³. Temperature sensors in the water and rock are used to evaluate the efficiency. Initial tests show a storage efficiencies of around 50%. The analysis of Freiberg yielded totally 4 districts well suited for a grid-connected heat supply including mine heat storage.
A contribution of the Austrian Institute of Technology (AIT) investigates the integration of three heat pumps (HP) of a total capacity in the range of 468 kW with borehole heat exchanger of 64 probes à 142 m for a residential district in Vienna, Austria. An unglazed solar collector and an asphalt collector are used for regeneration, while the BHE are also used for free cooling. The absorbed heat of the collectors also reduces of the urban heat island effect. Despite high potential for renewable energy use, challenges due to inefficient design, planning, and operational practices will be further investigated by monitoring data and optimization measure are derived.
At TH Nürnberg, the project “sEnSys” develops a holistic energy supply concept for multi-storey residential energy and climate neutral building retrofitting, which is implemented in a real demonstration building. The concept focuses on energy-efficient, resilient and smart building technologies, a predictive control strategy and cost-effective operation. The retrofitted building envelope also plays a decisive role in increasing the overall system efficiency. An energetic, economic and ecological assessment of retrofitting a MSRB based on different energy supply concepts and different envelope retrofit standards is presented.
The University of Innsbruck presented the Smart City Quarter “Campagne-Areal” Innsbruck which involves 16 new multi-apartment buildings in Passive House quality split in four project phases. The first four buildings with 307 apartments along with various commercial and public facilities were completed since late 2022. The buildings are heated by a central groundwater heat pump for space heating supply, while DHW is provided by the district heating. A comprehensive monitoring system offers detailed insights into the operation of the HVAC system. A dynamic building model has been developed and calibrated by means of monitoring data. The optimization focuses on improving the system design, as well as enhancing the control strategies. With improved operation the annual electricity demand of the heat pump can be reduced by 7.5% up to 15%. which aims to guide the design of the next project phases.
F. Azzini of the University of Bologna highlights in which way a systematic analysis of the real consumption data can drive the efficient energy management of the building stock. A methodology of data analysis tested with real data obtained from university buildings is presented. A building complex was used as a demonstrator. A Python script was used to automate the analysis of the available sub-hourly energy consumption data and demonstrated that the extrapolation of a series of key performance indicators useful for optimal energy management of the site is possible. The methodology was further applied to additional buildings to examine its applicability in identifying discrepancies between actual and expected consumption, highlighting all the singular behaviours which have to be corrected for the optimal energy management of each specific site of a building stock.
Lukas Oppelt of TU Bergakademie Freiberg presented a project with integration of seasonal water storage from abandoned and partially flooded mines in Saxony, Germany. A test storage system has been installed comprising a mobile heat pump test rig to store and extract heat cyclically in a basin of approx. 21 m³. Temperature sensors in the water and rock are used to evaluate the efficiency. Initial tests show a storage efficiencies of around 50%. The analysis of Freiberg yielded totally 4 districts well suited for a grid-connected heat supply including mine heat storage.
A contribution of the Austrian Institute of Technology (AIT) investigates the integration of three heat pumps (HP) of a total capacity in the range of 468 kW with borehole heat exchanger of 64 probes à 142 m for a residential district in Vienna, Austria. An unglazed solar collector and an asphalt collector are used for regeneration, while the BHE are also used for free cooling. The absorbed heat of the collectors also reduces of the urban heat island effect. Despite high potential for renewable energy use, challenges due to inefficient design, planning, and operational practices will be further investigated by monitoring data and optimization measure are derived.
At TH Nürnberg, the project “sEnSys” develops a holistic energy supply concept for multi-storey residential energy and climate neutral building retrofitting, which is implemented in a real demonstration building. The concept focuses on energy-efficient, resilient and smart building technologies, a predictive control strategy and cost-effective operation. The retrofitted building envelope also plays a decisive role in increasing the overall system efficiency. An energetic, economic and ecological assessment of retrofitting a MSRB based on different energy supply concepts and different envelope retrofit standards is presented.
The University of Innsbruck presented the Smart City Quarter “Campagne-Areal” Innsbruck which involves 16 new multi-apartment buildings in Passive House quality split in four project phases. The first four buildings with 307 apartments along with various commercial and public facilities were completed since late 2022. The buildings are heated by a central groundwater heat pump for space heating supply, while DHW is provided by the district heating. A comprehensive monitoring system offers detailed insights into the operation of the HVAC system. A dynamic building model has been developed and calibrated by means of monitoring data. The optimization focuses on improving the system design, as well as enhancing the control strategies. With improved operation the annual electricity demand of the heat pump can be reduced by 7.5% up to 15%. which aims to guide the design of the next project phases.
F. Azzini of the University of Bologna highlights in which way a systematic analysis of the real consumption data can drive the efficient energy management of the building stock. A methodology of data analysis tested with real data obtained from university buildings is presented. A building complex was used as a demonstrator. A Python script was used to automate the analysis of the available sub-hourly energy consumption data and demonstrated that the extrapolation of a series of key performance indicators useful for optimal energy management of the site is possible. The methodology was further applied to additional buildings to examine its applicability in identifying discrepancies between actual and expected consumption, highlighting all the singular behaviours which have to be corrected for the optimal energy management of each specific site of a building stock.