Australia // End User
TEST RESULTS FOR SELF-CONTAINED CO2 SYSTEM In September 2018, ALDI Australia began testing the world's first EptaBlue Natural CO 2 water-loop refrigeration system, from Italian OEM Epta, at a central Melbourne supermarket. (See “ALDI turns to water-loop CO2 in Melbourne,” Accelerate Australia & NZ, Summer 2019.) The system Is used in self-contained, plug-in cabinets, with heat withdrawn by the water loop. After several months of operation, Marcus Meier, ALDI Australia’s property director, revealed some conclusions from this test at ATMOsphere Australia 2019. The advantages of the system, Meier said, lay in three areas. First, the CO 2 plug-in units "provided excellent case temperature control," he said. Second, the solution makes sense for sites with engine -room space constraints — which was one of the original motivations to trial the system. "It's a good solution if you are in a mixed-use development where you don't have a plant room or you don't have a lot of space," Meier said. In this case, the system was installed as a refurbishment in a multi-story high-rise building in Melbourne's spaceconstrained central business district. Finally, the units are "ideal for sites with sensitive noise restrictions," he said. With regard to energy efficiency, however, the units did not live up to expectations. "The energy usage," Meier said, "is definitely not what we would go forward with at this stage.”
Accelerate Magazine // June 2019
At ATMOsphere Australia, Meier provided energyefficiency data on CO 2 transcritical systems at several stores using different configurations to boost efficiency, such as parallel compression and adiabatic cooling. He compared the energy use of those systems to that of R134a/CO 2 cascade systems running at comparable stores. The results, he said, were a bit sobering. The transcritical CO 2 systems, on average, were only about 2% more energy efficient than the cascade systems over one year. One of the reasons was the challenge of operating transcritical CO 2 efficiently during the summer. Though the systems were approximately 10% more efficient during winter months, they were 5% less efficient during the summer months, Meier said. In the summer months, some of the systems use adiabatic water sprays on the condensers to help lower the gas temperature as it exits the condenser. However, this raises another concern for ALDI: Water usage is high during these months and represents a risk to the business.
ELIMINATING WATER In order to mitigate this risk, ALDI is developing trials for a transcritical system that would eliminate the need for water sprays/adiabatics. Though still in the early stages, Meier said that the initial goals for the revised system include maintaining operational stability during summer months; completely eliminating water usage; and reducing operational costs. He did not disclose technical details about the system. Meier was confident that if ALDI achieves these goals, it could roll out transcritical CO 2 Australia-wide. "This, I believe, is where our future lies," he said. While it remains to be seen what results will be delivered by the trials, there is no doubt that ALDI Australia remains committed to natural refrigerants. "Here in Australia, we intend to innovate in the natural refrigerant space," said Meier. DY