Introduction of heat pumps in apartment buildings

Germany: In a joint project, the Fraunhofer Institute for Solar Energy Systems ISE, the Karlsruher Institute of Technology KIT, and the Inatech Institute for Technical Systems for Sustainable Development at the University of Freiburg, together with the housing industry, the heating and ventilation industry and energy suppliers, investigated the use of thermal systems. Conclusion - heat pumps can be used in old apartment buildings. Currently, the partners have developed appropriate information material for familiarization and practical implementation of these heating systems.

Heat pumps are a key technology in the transition to green heating, but their use in existing buildings is often quite challenging, also due to a perceived lack of experience among many market players. The typical multi-family building is considered particularly demanding due to the need to provide adequate heating system capacity, high fluid temperatures and the location of outdoor units in dense urban areas.

In the joint project LowEx im Bestand, the researchers used six buildings to demonstrate that heat pumps are also a viable option and how they are used is very important. Information material from project partners is intended to facilitate the implementation of these solutions.

Double reduction of climate-affecting emissions

“Heat pumps work particularly efficiently when used in LowEx systems, which are characterized by a small temperature difference between the heat source and the useful heat,” says Andreas Wagner, head of the department of building physics and technical development at the Faculty of Architecture at KIT.

“We have been able to prove that heat pumps can be used through different system settings – for example, combining different heat sources, replacing individual radiators or integrating an existing gas boiler in dual-mode operation – even in renovated older buildings, where they perform much more efficiently than usual. gas heating."

In addition to the savings, the researchers calculated that the CO2 emissions of heat pumps—cumulative over their lifetime in fully renovated buildings—are only about half that of comparable gas condensing boiler heating systems.

An integrated approach to the building

In their guide, the partners of the project, funded by the Federal Ministry of Economic Affairs and Climate Protection BMWK, demonstrate that simple measures, such as replacing individual radiators, are often sufficient to reduce the temperature of the heating circuit, and this is decisive for the efficiency of the heat pump.

By this, experts contradict the popular opinion about the need - in each case - to replace all radiators or install heated floors.

Dr. Marek Miara, heat pump coordinator at Fraunhofer ISE: “In general, the use of heat pumps in apartment buildings is possible and has already been proven in practice. The variety of apartment buildings and their characteristics make it possible to apply different technical solutions based on heat pumps.”

However, heat pumps have not yet received truly widespread use in apartment buildings. The reasons are administrative and technical. For the widespread use of heat pumps in apartment buildings in the future, standard solutions must become indispensable.”