There should be six million heat pumps by 2030.
But the discussion about highly toxic refrigerants could call these ambitious goals of the energy transition into question.
Berlin – The heat pump is considered to be the heating system of the future because it generates thermal energy from the ambient air – it is electrically operated with high efficiency.
For climate protection and independence from fossil fuels, the federal government is planning to install six million heat pumps by 2030.
This goal could now be stumped by the debates about the refrigerants used in the pumps.
Because some of these are highly questionable.
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Climate protection versus health hazard: heat pumps as an alternative heating system - but they can be harmful to health
© Silas Stein/dpa
Heat pumps as a heating alternative - they can damage health and the environment
A new draft law from the Ministry of Economics has just caused a stir.
Economics Minister Robert Habeck (Greens) wants to introduce a general ban on new oil and gas heating systems from 2024.
Heat pumps are thus coming into focus as a particularly promising, because climate-friendly heating alternative.
A Hamburg study also came to clear results in a direct comparison with hydrogen as a heating alternative.
Unfortunately, the energy-efficient heating systems have a crucial Achilles heel: their refrigerants.
Can toxic coolants in heat pumps endanger the energy transition?
Even if the refrigerants in heat pumps are actually in a hermetic circuit, they pose a huge problem during production, or at the latest during disposal, because they often contain dangerous gases from per- and polyfluoroalkyl substances (PFAS).
If these “poisons of the century” get into the environment, they will presumably never disappear there again.
What are PFAS?
PFAS is the acronym for Per- and Polyfluorinated Alkyl Substances, a group of industrial chemicals that includes about 4700 substances.
They are used in the manufacture of many products because of their water, grease and dirt-repellent properties.
PFAS are found in a wide variety of industrial and consumer products, including textiles, packaging, fire suppressants, lubricants, solvents, surface treatments and foams.
However, PFAS are also hazardous to the environment and can pollute water, soil and air and pose a risk to human health.
These substances do not occur naturally and are considered to be persistent chemicals, which means that once they are released into the environment, they will probably never disappear.
The substances can also be detected in blood and tissue and are suspected of causing cancer in humans, making them infertile and weakening the immune system.
The so-called eternal chemicals PFAS, which are in many of the pumps, are not only considered to be difficult to degrade, but also highly toxic.
In studies, the carcinogenic chemicals were detected at over 1500 locations in Germany.
Heat pump as a poison: PFAS poison of the century in the refrigerant
The EU is now even examining a far-reaching ban: Five European countries, including Germany and the Netherlands, want to ban the production and use of this sensitive group of substances throughout the EU.
The proposal to restrict PFAS has been submitted to the European Chemicals Agency (ECHA).
The EU Commission will therefore foreseeably decide on restrictions together with the member states.
This role is played by the coolant for the heat pump heating system
A heat pump consists of a closed-loop system that contains a refrigerant and works in a similar way to a refrigerator.
First, the refrigerant is vaporized in an evaporator at a low temperature, whereby it absorbs heat from the environment (e.g. air, ground or water).
The vaporous refrigerant is then brought to a higher temperature and pressure by a compressor and liquefied again.
The absorbed heat is released to the heating system.
The choice of refrigerant is important for the effect of heating on the climate.
Because some of the chemicals in the atmosphere increase the greenhouse effect enormously.
The GWP (Global Warming Potential) value of some of these agents is several thousand times higher than that of the same amount of CO₂.
Individual refrigerants are therefore already being gradually banned.
The lower the value, the more climate-friendly the heat pump is - we recommend, for example, the refrigerant R32 with a GWP of 675. Many devices run with the refrigerants R410a or R404a, which have a GWP of over 2000.
Heat Pump Association against ban on dangerous PFAS
But the Federal Association of Heat Pumps (BWP) is critical of a ban.
Managing Director Martin Sabel explained in an interview with the
Süddeutsche Zeitung
that the heat pump "plays an outstanding role" in turning away from fossil fuels.
However, stricter rules would jeopardize the important European climate goals and "prevent or at least significantly slow down the urgently needed, rapid decarbonization of the building sector".
Consumer center advises: Pay attention to alternatives with a low GWP value
The fact is: there are already alternatives.
And they are not only less harmful to nature and people, but also more environmentally friendly.
The so-called GWP value is an indicator for more compatible refrigerants.
The lower this value, the more climate-friendly - and usually also more environmentally friendly - is the refrigerant circulating in the heat pump.
“Explicitly order a heat pump with a low-GWP refrigerant.
These are often natural substances, such as propane," advises the consumer center.
Expert: "It is possible to operate almost all heat pumps with natural refrigerants"
However, the Federal Association of Heat Pumps criticizes the safety risk of propane, saying that it can ignite relatively easily.
The scientist Clemens Dankwerth from the Fraunhofer Institute for Solar Energy Systems (ISE), who is researching the future of heat pumps with his colleagues, counters this:
"It is absolutely possible to operate almost all heat pumps that are used in buildings with natural refrigerants," he told Süddeutsche.
The pump his team developed would need no more propane than a camping stove...
List of rubrics: © Silas Stein/dpa