Aleksej Pavšukov, CEO of Lithuanian HVAC&R manufacturer Refra, said the company is targeting the Middle East market with its newest product, an air-cooled CO2 (R744)/propylene (R1270) refrigeration unit.
“Our cascade product is the answer to the question: ‘Where are natural refrigerants for the Middle East?’” Pavšukov told NaturalRefrigerants.com during an interview at Chillventa 2024. “We’re showing the Middle East that you can have a CO2 system, but it should be subcritical.”
The Refra Cascade System uses propylene to subcool the CO2 to ensure the system runs in subcritical mode even in high ambient conditions. It features a Bitzer compressor and inverter, an Alfa Laval heat exchanger, GBM pressure vessels and Danfoss line components.
“Our cascade product is the answer to the question: ‘Where are natural refrigerants for the Middle East?’”
Aleksej Pavšukov, CEO of Refra
The unit at the show has a refrigeration capacity of 39kW (11.1TR) and was built for a German bakery, the name of which Pavšukov said he could not share. Along with food processing, Refra’s CEO said the company is also targeting the supermarket sector.
“You can use the low-temperature [LT] CO2 subcritical unit for the LT coolers with direct expansion, and all the medium-temperature equipment could be served by glycol.”
While cascade refrigeration systems are not new, Refra’s CEO said the plug-and-play, monobloc design of its Cascade System makes it unique.
“You just install it and go,” he added.
Demo on display
The company also brought an air-to-water high-temperature heat pump (HTHP) to Chillventa capable of outlet temperatures of 80°C (176°F) that uses R436A – a blend of propane (R290) and isobutane (R600a) – as a refrigerant. Pavšukov said the blend of hydrocarbon refrigerants enables Refra to “maintain low pressure while having a high outlet temperature.”
“We use our standard propane air-to-water heat pump to heat the water from 30 to 35°C [86 to 95°F], and then we boost it with the water-to-water isobutane system,” he said.
The demo unit at the show has a heating capacity of 450kW (127TR) and uses 17kg of R436A per circuit. It will undergo winter testing at the company’s factory in Vilnius, Lithuania, where Pavšukov said temperatures can dip as low as −30°C (−22°F). The HTHP will be used to heat Refra’s factory, with the test period expected to end in March 2025.
“I see this product as serving old factories that still have radiator systems because they need 80°C [176°F] and can’t go lower because the efficiency of the system will not heat up the building,” he said.
Pavšukov said part of the test period will also involve “challenging” the Bitzer compressors to see if the system is capable of providing outlet temperatures of 85 to 87°C (185 to 188.6°F).
In addition to factories, Pavšukov said he can see the HTHP being used to provide district heating in Central and Southern Europe. He said those areas are particular targets because the unit isn’t able to reach 80°C in very low ambient temperatures.
“We want to show that it’s not only CO₂ that can handle district heating,” Pavšukov stated. “We don’t need a big delta T. We can work with a delta T of 20, 15 or even 5°C [68, 59 or 41°F].”
