A collaborative effort to manufacture affordable “Smart CO2” (R744) heat pumps for small commercial operations, including apartment buildings, will serve both space and water heating, a departure from industry norms.
Most commercial CO2 heat pumps to date have been reserved for domestic hot water heating, but not space heating.
The project is supported by EUDP (the Energy Technology Development and Demonstration Program), a Danish program that co-finances via public funding the development and demonstration of new solutions within energy technology.
“The whole purpose of this project is to develop a commercially available [CO2] heat pump, in the range from 20 to 200 kW [5.7 to 56.9TR],” said Henrik Christensen, Managing Director of Danish manufacturer Reftronix, in an interview at EuroShop 2023. The event was held from February 26 to March 2 in Dusseldorf, Germany. Reftronix is supplying the controls and cloud technology for the heat pump.
“This will become a commercial and available product that provides both hot tap water and space heating,” Christensen said, noting that it offers both air-to-water and water-to-water heat exchange. A prototype will be tested this summer, he added.
“[This heat pump] is an alternative to HFOs, but it should have the right price point,” Christensen said. “The gigawatt heat pumps are too expensive for this segment of the market. They needed something smaller with a controller; that is where we came in.”
While CO2 is a challenging refrigerant to use, the advantage is it delivers the higher temperatures required by older radiator systems, making it a “cost-efficient” replacement for gas and oil furnaces, he noted.
If an end user only needs water heated to 50°C (122°F), which works for the floor heating in new construction, “CO2 is lousy,” Christensen said, explaining that propane (R290) would be preferable. But for older systems, propane cannot get the water hot enough for space heating. “The COP of propane drops if you try to heat water to the high end [60 to 70°C (140 to 158°F)],” he added.
According to Christensen, Danish OEM Fenagy, a subsidiary of Beijer Ref, will own the final product produced from this collaboration.
Along with Reftronix and Fenagy, the collaboration includes Swedish OEM Alfa Laval, Italian OEM Lu-Ve, Danish OEM Danfoss, German OEM Kelvion, the Danish Technological Institute and Aarhus University.
Moving away from fossil fuels
The CO2 heat pump collaboration continues Reftronix’s efforts to provide “cost-effective” options for older buildings to get off of fossil fuels. Last year, Reftronix announced it had developed a CO2 heat pump prototype for residential homes from a converted R32 heat pump using a 2HP Panasonic compressor.
The residential prototype was developed in partnership with Danish refrigeration contractor Temp-Tech with funding from the government group Energy Cluster Denmark.
“There are rumors that CO2 systems are way too complex and expensive,” said Fred Schmidt, CO2 Process Control Expert for Reftronix. “So we said, ‘Let’s make it simple and reduce the components to a minimum to keep the price down.’”
There are many homes in Europe built from the 1950s to 1970s that need updating, said Christensen. “You could insulate the homes and put in more efficient radiators, but that is just too expensive. A CO2 heat pump is the right choice for older homes.”
With local plumbers having more experience with boilers than heat pumps, a lot of training still needs to go into updating systems, Christensen added.
“The whole purpose of this project, which is EU-funded, is to develop a commercially available [CO2] heat pump, in the range from 20 to 200 kW [5.7 to 56.9TR].”Henrik Christensen, Managing Director at Reftronix