“We even have them in the California desert, where we’ve seen 120°F (49oC) on the roof,” Atkinson said at the Hillphoenix table at the Food Marketing Institute’s Energy & Store Development Conference, held in New Orleans, September 11-14. One of those desert locations is Palm Springs, California, he said, though he declined to name the retailer operating there.

Transcritical systems typically operate less efficiently when ambient temperatures exceed the critical point of CO2, about 88°F. So to work efficiently, the transcritical units in the desert employ a Trillium adiabatic cooler from Baltimore Aircoil, which applies water-assisted cooling, said Atkinson. Hillphoenix is also developing transcritical systems with other efficiency-improving technologies like parallel compression and ejectors; it has one parallel compression system in the field.

Overall, Hillphoenix is seeing “rapid growth” in transcritical adoption in North America, said Atkinson. “A lot of retailers are moving from trials to standardization.”