Guidelines for heat pumps in existing buildings published

27.03.2024

Source: Energy & Management Powernews

Until now, the heat pump was seen more as a solution for energy-optimized new builds. A Dena guideline now aims to leverage the potential of the technology in existing apartment buildings as well.

The switch to heat pumps in apartment buildings offers enormous potential for achieving the goal of climate neutrality by 2045. This is stated by the German Energy Agency (Dena) in its new guide. It shows possible applications for heat pumps in existing buildings with several apartments and presents solutions and practical examples. The guide was produced as part of Dena's "Building Forum Climate Neutral" project in collaboration with the German Heat Pump Association, the German Housing Industry Association (GdW) and the Fraunhofer Institute for Solar Energy Systems (ISE).

The collaboration is part of the German government's heat pump campaign. "With the Heat Planning Act, the Building Energy Act and the federal funding for efficient buildings, the framework for the necessary investments in existing buildings has now been set," said Christian Stolte, Head of Climate Neutral Buildings at Dena. Heat pumps would play a central role in the future.

"There are particular challenges in using them in multi-family buildings in existing housing stock and there is still little experience with them," Stolte admitted. Therefore, the exchange and networking of specialist players must be further intensified and expanded. This also applies to the area of operational monitoring and optimization. "With the new guide, we are reflecting the current level of knowledge and experience in practice and want to support experts with the bundled findings in implementation," explained Stolte.

Tenants satisfied in eight projects

"The socially oriented housing companies are working flat out to implement the climate targets in existing buildings, particularly through the use of heat pumps," added GdW President Axel Gedaschko. The technical expertise is available, but affordability is a major challenge for landlords and tenants. "Housing companies and their tenants urgently need better financial support in view of the enormous investments required," he demanded. In the eight projects examined for this guide, the tenants were also satisfied with the changeover. Early involvement and communication proved to be a key factor here.

"From a technical point of view, there is a lot to be said for using heat pumps in existing buildings," said Peter Engelmann, co-author and head of the Building Systems Technology Group at Fraunhofer ISE. Heat pumps can work very well with existing radiators, for example, and tapping into the source of environmental heat is often possible without any problems. "Manufacturers and installers are prepared for a strong increase in demand for heat pumps for multi-family houses," assured BSW Managing Director Martin Sabel.

The industry offers a broad portfolio of technical solutions, from central heat pumps in the boiler room to decentralized solutions for floor heating systems and local heating networks with large heat pumps. Sabel also referred to the new regulations of the Building Energy Act, according to which new heating systems must use at least 65 percent renewable energy from 2028 at the latest. "The heat pump directly fulfills the requirements of the Building Energy Act and also improves the efficiency class of the newly connected building," said Sabel.

Note special challenges

In contrast to smaller residential buildings, heat pump projects in apartment buildings present special challenges. These include, for example, the tight development in inner-city areas or the conversion of decentralized systems such as gas floor heating or individual stoves as well as the high temperatures in central domestic hot water heating. However, there are also solutions for these conditions with innovative components such as thermally usable photovoltaics, decentralized heat pumps and home stations, according to the guide.

Grid-connected district solutions are also an option. The guide explains that there are also a wide range of solutions for buildings with low thermal insulation and radiator use, with various heat sources from air, ground and water. Reducing heating temperatures is crucial for efficient operation and low operating costs. Heat pumps can be supported by peak load boilers. Improving the thermal insulation will allow the heat pump to be the sole source of heat supply in the future.

The practice guide for heat pumps in apartment buildings is available to download as a PDF.

Author: Susanne Harmsen