Heat pumps on R290: Efficient, environmentally friendly and PFAS-free

The natural refrigerant R290 (propane) is known for its thermodynamic properties, making application in the heating sector popular. Moreover, since R290 heat pumps do not require the addition of PFAS, they operate efficiently, environmentally friendly, safe and sustainable in terms of the F-Gas Regulation. Maarten Ouwehand, Heating Team Leader at WOLF Energy Systems, explains the benefits of R290.

"In addition to efficiency, more and more attention is being paid to the environmental properties of the refrigerant used when evaluating heat pumps," he says. "There are good reasons for this, because many synthetic refrigerants contain harmful Poly- and perfluoroalkyl substances (PFAS)." PFAS are considered toxic and are therefore banned throughout Europe. "Because they are very poorly biodegradable (perpetual) chemicals, they accumulate in the environment and eventually in the human body. Here they can damage the liver and cause thyroid disorders, obesity, fertility problems and cancer."

Natural and environmentally friendly 

In contrast, the natural refrigerant R290 is a truly "clean agent," according to Ouwehand. "It is a natural, almost infinitely available hydrocarbon with excellent refrigeration properties. R290 is not harmful to the ozone layer and has a very low Global Warming Potential (GWP) of 3, while its thermodynamic benefits are great.

- Supply temperatures possible up to 70°C, even at low outside temperatures.

- High COP of 4.65 at A2/W35 according to EN14511.

- High EER of 5.92 for A35/W18 according to EN14511.

The latter value is especially interesting if the heat pump is used for both heating and cooling."

Maximum safety

The only disadvantage of R290 is its flammability. This is why the refrigerant is classified in safety group 3 according to DIN EN 378 (Refrigerating systems and heat pumps - safety and environmental requirements). "In the WOLF CHA monoblock heat pump, safety is ensured by completely housing the cooling part in a hermetically sealed circuit in the outdoor unit. The heat is transferred to the building via water. This also eliminates the need for a refrigeration certificate for the installation. Any leaks of the refrigerant, which is naturally occurring anyway, do not cause any environmental or health risks for installers. They do not have to intervene in the refrigeration circuit, which is already filled at the factory. Precise installation specifications ensure maximum safety."

F-gas regulation speaks for R290 

Another aspect that speaks in favor of R290 is the F-gases regulation that has been in effect since Jan. 1, 2015. "Whereas most refrigerants previously used in heat pumps are now classified as harmful to the climate, the F-Gases Regulation explicitly exempts propane from the ban on climate-damaging and ozone-depleting refrigerants," says Ouwehand. The goal of the F-Gases Regulation is to drastically reduce the use of hydrofluorocarbon-based refrigerants (HFCs) in a phased plan. The regulation should lead to a reduction of CO2 equivalent to 21% by 2030. There are also bans on the continued use of HFC refrigerants in certain application areas. "Experts assume that this gradual volume reduction (F-gas phase-out) and the associated shortage of refrigerants with high GWP will lead to huge price increases and technical disruptions in the market. Especially systems that require regular maintenance will be affected by the price increase."

GWP as the most important parameter 

Since 2015, the so-called GWP value has determined refrigerant selection. "This GWP value defines the average warming effect of a chemical compound or refrigerant on the earth's atmosphere over a 100-year period, compared to the same amount of carbon dioxide (CO2)," Ouwehand explains. "So it corresponds to the CO2 equivalent of a chemical compound. The refrigerant R290 has a GWP value of 3 and thus only a minimal greenhouse effect." The ODP value, the ozone-depleting potential of a refrigerant, is another characteristic value that describes the properties of a chemical compound. "The ODP value describes the relative effect of ozone depletion that can be caused by a substance. The reference value for the ODP value 1 is R11 (Trichlorofluoromethane). Values above 1 are more ozone-depleting, while values below 1 are less ozone-depleting." R290 has an OPD value of 0.

Excellent choice

A ban on the use of F-gases in split air conditioners and heat pumps recently came into effect from the EU, which will take effect in 2035. "This decision fits into the trend of phasing out refrigerants with a high GWP and the wide application of refrigerants with a low GWP," Ouwehand said. "Refrigerants with a high(er) GWP value will become increasingly expensive to maintain as the refrigerant becomes scarcer. This means that current (low-priced) heat pumps with high GWP refrigerants may have high follow-up costs for maintenance and disposal. If, on the other hand, one chooses an R290 heat pump, then one can be sure that - during the estimated lifetime of the heat pump - there will be no additional costs due to a refrigerant shortage." In the medium term, he said, there is no significant alternative to natural refrigerants in terms of environmental compatibility, efficiency and availability. "Refrigerant R290 continues to convince. It is safely controllable, cheap and efficient to use, making it an excellent choice."