HP-QA in Existing Buildings (WP-QS im Bestand)

To achieve the climate protection goals in the building sector, heat pumps can play a key role in cost-effectively restructuring the heat supply in buildings. In order to assume this role, heat pumps must become a central technology for the heat supply in existing buildings. In order to facilitate the necessary expansion, various hurdles need to be overcome in general, particularly in existing buildings.  Of assistance here is the demonstration and analysis of the efficiency of heat pumps under typical conditions in existing buildings and the development of suitable measures to ensure efficiency. The BMWi-funded research project "WP-QS im Bestand” (Heat Pumps-Quality Assurance in Existing Buildings) (FKZ: 03EN2029A) is dedicated to this and other topics and focuses on the single-family homes.

The research questions addressed in "WP-QS im Bestand" can be divided into the following three categories.

Energy performance and environmental impacts

• How efficient are heat pumps in existing buildings and what are the decisive factors affecting the overall system? What contribution have the technological developments over the last ten years made? What measures are lacking in order to perform measurement analysis and evaluations on the new systems, e.g. hybrid heat pumps, various combinations of heat pumps, photovoltaics and battery systems?
• When is the use of bivalent systems reasonable and how should they be dimensioned and controlled?
• How high is the actual noise pollution of outdoor air source heat pumps in the field?

Sector coupling

• How should heat pump/PV combinations be dimensioned and controlled with regard to self-consumption and the interaction with the electricity grid?
• How should heat pump operation be evaluated with respect to developments regarding carbon emissions and primary energy consumption in the heat and electricity sectors?

Quality assurance in the retrofitting process

• How shall the process proceed, starting with taking stock of the existing heat supply, through the conceptual design and selection of the heating supply system up to the plant commissioning? Where are the possible risks and what measures can be taken to avoid them?
• How can standardized processes be integrated into the planning concepts, e.g. individual energy retrofitting plans for each building?

To answer these questions, we will carry on with the field measurements conducted in the project  »WPsmart im Bestand« addressing more detailed and other questions as well as additional systems; where the focus will be on bivalent systems and PV/HP combinations. The efficiency analysis will be extended by a model-based approach. For the PV/HP combinations, proposals for optimizing the efficiency of PV self-consumption will be developed and implemented. The basis for determining the noise levels caused by outdoor air-source heat pumps lies in the development of a reliable measurement concept in which differentiation between the different noise sources is guaranteed. Surveys and workshops will be held with the stakeholders involved in order to analyze the process of the energy retrofit with heat pumps.