THE first chillers using the new HFO refrigerants are being trialled by Waitrose at its supermarket in Bromley, Kent.
Believed to be the world's first such installation, the Italian-made Geoclima chillers are based on Frascold reciprocating compressors and operate on Honeywell's HFO R1234ze.
The supermarket chain which announced two years ago that it was to switch to using hydrocarbons for all future new stores and refurbs has opted to trial one of the new so-called fourth generation low GWP HFOs.
The system uses two 180kW chillers with Frascold semi-hermetic compressors providing chilled water as a condensing medium for the in-store integral cases running on propene.
Although measured over a relatively short period of time, initial comparisons to a same-size store in Canterbury running identical systems on R290 (propane) is said to have shown a 22% reduction in energy consumption.
If the trial is successful, Waitrose plans to adopt the HFO solution as part of its refrigeration platform for future stores, along with the continued use of hydrocarbons and tri-generation energy centres where appropriate.
Jim Burnett of Waitrose said: 'We believe the HFO solution shows great promise, as it combines good efficiency with very low global warming potential. This is obviously a highly desirable profile in a refrigerant. If the ongoing monitoring of energy continues to prove successful, we plan to include HFO-based chillers in our choice of refrigeration platforms for stores in the future.'
Tim Mitchell of Klima-Therm said: 'The focus at the moment is on HFO R1234ze, as the refrigerant is already available at commercial levels. In the longer term, we are also interested in the potential of HFO R1234yf, which has an even lower GWP and potential other benefits. This is one for the future, but it is in our sights.'
Tests carried out by Frascold with its eight-cylinder reciprocating compressors W40168Y running on HFO R1234ze indicate a loss of capacity of around 24 percent compared with R134a across various application conditions. However, mean power absorbed is almost 27% less, giving an overall COP actually better than R134a across a range of applications and conditions.
Frascold's research and development team believe that performance with HFOs can be significantly improved with further optimisation.