Increasing climate change and the war in Ukraine make it clear to us how important independence from fossil fuels is. New, innovative heat pump systems should therefore make the supply of buildings with space heating and hot water more independent and environmentally friendly. In practice, however, there are considerable hurdles when retrofitting existing buildings.
In order to achieve the climate targets set and more energy independence, the federal government is planning a 100 billion euro package. Among other things, these funds are intended to support technologies that can be used to save CO2 when heating living space. Above all, energy-efficient heat pumps should enable the provision of space heating and hot water in the future – and at the same time significantly reduce the consumption of energy from fossil fuels.
Heat pumps for heating living space do not require combustion processes, because they convert heat from the environment so that it can be used for heating processes in the home. This works in a similar way to a refrigerator, which extracts heat from its interior and emits it to the environment. In a heat pump, the ambient heat from the air, soil and groundwater is transferred to a refrigerant via a heat exchanger. This is the key element of the heat pump because it has a very low boiling point. As a result, even a small amount of heat can cause the refrigerant to evaporate. The now gaseous refrigerant is compressed with a compressor, whereupon it heats up considerably. This heat can then be fed into the heating system of the respective building.
How independent and effective are heat pumps?
However, heat pump systems can only be really independent of fossil energy sources if the electricity for commissioning and the production of the required materials works without using fossil fuels. Energy experts led by Immanuel Stieß from the Institute for Social-Ecological Research in Frankfurt am Main have now examined how advanced the technologies are in these areas. One of the results of their study: Heat pumps are particularly efficient as part of so-called trigeneration systems that combine heat, cold and electricity generation. In order to minimize energy dependency, the in-house heat pump could be operated with solar energy on the roof, for example.
“The use of solar energy on your own roof makes the operation of these heat pumps particularly energy-efficient, self-sufficient and cheaper than fossil-fuelled heating systems,” explains Stieß. The new innovative heat pump systems also do without synthetic refrigerants, which have a very high global warming potential. Instead, they use natural refrigerants such as propane or CO2, which makes them particularly environmentally and climate-friendly in operation. “In this combination, trigeneration systems represent the technology for heat pumps of the next generation, a key technology on the way to more sustainability and more independence from fossil fuels,” says Stieß.
obstacles to implementation
But according to the ISOE researchers, technology alone does not make climate protection. These innovations must be known and accepted by architects, owners and installers. “In dialogue with the players in practice, we saw that the greatest challenge for the installation of heat pump systems lies in the building stock,” says Stieß. Because the planning and installation is initially associated with a lot of costs and effort. There is often a lack of designs that make it easier for architects and heating engineers to adapt the installation of heat pumps to individual buildings. Stieß explains that technicians and installers often lack specialist knowledge of the innovative heat pump systems and must therefore be given further training.
However, according to Spieß and his colleagues, there is a good chance, at least in new buildings, to establish more energy-efficient systems. To improve market acceptance, they recommend that heat pumps should become more standardized and easier to install. In order for the systems to be more practical, it is also important to develop compact and space-saving systems and to ensure that the devices can be combined with components from other manufacturers. A simplified application for subsidies for heat pump systems could also make the technologies more attractive. Even if many hurdles still have to be overcome before heat pumps can be used across the board, the experts classify these systems as crucial for saving CO2 and greenhouse gases in the building sector.
Source: Institute for Socio-Ecological Research (ISOE)