In April, Australia’s first transcritical CO2 system to utilise an ejector was installed at a newly rebuilt Ritchies IGA supermarket in Beechworth, Victoria.
The system encompasses the store’s entire heating and cooling needs – including air conditioning and heating during the summer and winter seasons – and is one of a number of stores the retailer is looking to open with fully integrated transcritical CO2 systems this year.
Dave Redden, principal at local refrigeration consultancy Refrigeration Innovations, and lead consultant for the project, has had a long relationship with the folks at Ritchies. For both parties, the move to natural refrigerants was in discussion for a long time, including close monitoring of CO2 technology and overseas trips, which finally led to this first installation in April.
“Ritchies already decided some time ago that all new greenfield sites and major refurbishments would be with CO2 transcritical systems,” says Redden.
“As we were looking at different options for different [transcritical CO2 systems], we decided that the Beechworth store would be the first one. We also decided that we would use the Danfoss gas ejector system since it would get us across the line for the warm climate refrigeration.”
Boosting efficiency in warm climates
The efficiency of transcritical CO2 systems in warm climates has long been seen as a barrier to implementing the technology in certain regions of Australia. However, over the past few years, technology innovations such as parallel compression, ejectors, sub-cooling and adiabatic cooling have opened the door to the efficient use of CO2 in warm regions around the world.
The transcritical CO2 system at Ritchies IGA in Beechworth uses both parallel compression and ejectors to create a buffer against the area’s warm summer temperatures.
“We’ve run it when we commissioned the store,” Redden explains, “because it was quite warm still in autumn at the time”.
“It was between 29°C and 31°C most days, and it worked very well.”
“Since then obviously it hasn’t been running because it’s very cold up there at the moment. But we’ll wait until the next warm period hits – probably around December – when the system will come into its own again,” he says.
A game changer
For Ritchies and Refrigeration Innovations, HFCs are already a thing of the past. In fact, their discussion of the move to natural refrigerants began several years ago and hit a turning point after overseas trips to Europe.
“We discussed it over a period of about four or five years, that there was a change coming,” says Redden.
“And I don’t think it was until [Ritchies] went to Europe and saw everything on CO2 that it really hit them that this change had to be managed – because it’s a game changer you know, a big dollar value.”
Ritchies and Redden, however, see this game changer as a promising one with a long-term payoff. A few more installations for Ritchies with transcritical CO2 systems are already in the works for the next year, according to Redden.
“We are monitoring power and usage pretty carefully at the moment, comparing it to the old store, which basically used R404A racks, and we’re already seeing some quite good savings on it, mainly due to utilising waste heat to heat the store.”
Asked how he sees the outlook for uptake of CO2 systems with warm-climate innovations like ejectors in Australia in the future, Redden replies, “I think they are a good answer”.
