EjectorDENMARK: Danfoss has revealed that ejector technology for use in CO2 refrigeration systems could be ready for market launch in the near future.

In a presentation at last week’s Atmosphere Europe 2016 Torben Funder-Kristensen, application and technology specialist at Danfoss, revealed that, based on the results and recommendations from successful tests in four European supermarkets, ejector solutions may be ready for market launch in the near future.

The four transcritical sites represented different set-ups in terms of size, ambient temperatures, refrigeration only/combined refrigeration and air conditioning and systems with and without heat recovery. According to Funder-Kristensen, the results across sites and systems verified the positive assumptions linked to the ejector technology in the refrigeration community.

“We are happy to see that the test results from the four sites confirm our predictions on ejector efficiencies,” said Torben Funder-Kristensen. “The tests also underline that we are following our plans for technology maturation so that ejector solutions may be ready for market launch in the near future.”

In addition to the most recent tests, Danfoss says it has run similar tests on more than ten sites across Europe. The accumulated real-life results are said to show that the ejectors achieved efficiencies of up to 30% over several hours.

Danfoss-ejectors

There are two different types of ejectors. Large scale ejectors (top) can vary the capacity through flow restriction in the nozzle. Fixed optimised geometry ejectors in parallel operation (above) can vary the capacity by partial on/off operation

High energy efficiency is achieved by recovering the energy taken out while reducing the pressure from the gas cooler to the liquid line pressure. The ingenious solution reduces the workload of the compressors, while still ensuring that the cooling demand is met.

The trial set-ups have shown that the simple ejector technology can increase the efficiency of the parallel compression system as much as when going from no parallel compression to parallel compression. According to Danfoss, the energy saving potential compared to traditional HFC systems is significant. Furthermore, the ejector technology allows smaller and more compact compressor packs to be installed, reducing the first cost of the installation.

“The tests pave the way for successful ejector application in future solutions and provide us with a deeper understanding of the implications for system design when using this new technology,” Funder-Kristensen added. 

Danfoss is developing ejector solutions for food retail in close cooperation with refrigeration specialists from SINTEF, the Trondheim-based independent research organisation.

Danfoss-four-test-sites

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