Waitrose first to put HFO chiller in store

Waitrose is carrying out an energy assessment in a working store of what is believed to be the world’s first supermarket installation of a packaged HFO chiller.

The Geoclima units were developed and optimised by bespoke chiller specialist Klima-therm using Frascold reciprocating compressors and use Honeywell’s Solstice branded HFO-1234ze as refrigerant.

The Waitrose team will be talking about how this development fits in alongside its Cooling Award winning hydrocarbon-based platform at RAC’s Retail Question Time on November 29. See the Retail Question Time box above for details.

The two air-cooled HFO machines, each rated at 180 kW, will provide chilled water as a condensing medium for the in-store integral cases running on R1270 propene. They were comprehensively tested in the Geoclima factory before being supplied by Klima-Therm to the Waitrose store in Bromley, south-east London.

Initial comparisons to a same-size store in Canterbury running identical systems but using R290 propane as the refrigerant show a 20 per cent reduction in energy consumption for the HFO machines.

If the trial is successful, Waitrose plans to adopt HFO chillers as part of its refrigeration platform for future stores, along with the continued use of hydrocarbons and tri-generation.

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.”

Giuseppe Galli, managing director of Frascold, said: “From a compressor engineering point of view, the properties and operating characteristics of HFOs are a very good match for traditional refrigerants, but obviously without the environmental penalty of high GWP HFCs.”

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 percent less, giving an overall COP 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. This could include refinements to the valve plate design, motor sizing and reducing pressure losses through the compressor.

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