A Carrefour supermarket in Diepenbeek, Belgium, has saved up to 15% in energy use at 25°C (77°F) ambient temperature by using two PX G1300 pressure exchanger devices from U.S. manufacturer Energy Recovery in the store’s transcritical CO2 (R744) system.

“The PX G1300 reduced compressor power [in the Carrefour store’s system] from 99kW to 84kW,” said KC Chen, Vice President for CO2 at Energy Recovery. The store has a total cooling capacity of 280kW (79.61TR).

These findings were presented by Chen and Stien Develtere, Purchaser with Belgian refrigeration cooling rack and service provider Fieuw Koeltechniek, at ATMOsphere (ATMO) Europe Summit 2023, held September 19–20 in Brussels. The event was organized by ATMOsphere, publisher of R744.com.

In February, Energy Recovery announced Fieuw Koeltechniek as its exclusive distributor in the Benelux (Belgium, the Netherlands, and Luxemburg) region of its PX G1300 device, designed to improve the efficiency of transcritical CO2 systems in commercial and industrial applications. Fieuw works with a sister company, HVA Koeling, a CO2 rack installer in DX and pump cooling. Develtere called the PX G1300 an “impressive device.”

Energy Recovery and Fieuw have developed an easier way for customers to purchase and install the PX G1300 into their refrigeration systems regardless of system capacity, commercial or industrial application, or new or existing system. This partnership resulted in the PX G1300 “Energy Efficiency Module,” an add-on for existing CO₂ installations, he added.

The Carrefour supermarket was Fieuw’s first installation of the PX G1300 Energy Efficiency Module. Develtere noted that Fieuw already has five other store installations of the PX G1300 in the pipeline, which are expected to finish by the end of this year, including at a couple of Delhaize stores. In addition, Fieuw has started installation of PX G1300 devices into a CO2 pump system for a big pancake factory in the West Flanders province of Belgium.

“I think we have a great innovative product, and we are looking forward to many more PX G1300s to install,” said Develtere.

New California store installation

Chen noted that installing the PX G1300 in a Vallarta supermarket in Indio, California, which has similar architecture to the Carrefour location, has resulted in up to 30% peak energy savings.

Energy Recovery and Vallarta announced that they plan to install the PX G1300 device at a second Vallarta store in Salinas, California, while presenting at ATMOsphere (ATMO) America Summit 2023 on June 12 in Washington, D.C. Energy Recovery also won the Innovation of the Year award during the same event.

Energy Recovery invented the pressure exchanger device 25 years ago, and has deployed them in several industries, notably water desalination. “Over 30,000 PXG units are deployed throughout the world,” said Chen. “Most of them are still running as PXGs are designed for 25 years of service life.”

The longevity of the device is due its design, which includes only one moving part, explained Chen. “At the same time, the internal parts are made of highly engineered ceramics,” he added. “There are no bearings, no seals, and everything is hydrostatic. So, we are very, very proud of this device.”

In addition to energy savings, Chen highlighted that PX G1300 offers potential CAPEX savings with its reliability and potential reduction of components like parallel compressors, main compressors and adiabatic coolers. The PX G1300 also helps to maintain high-temperature stability in the CO2 racks, while its self-contained design enables the addition of multiple PX G1300 units as needed to increase system capacity, he noted.

Chen explained that the PX G1300 recovers the energy from the high pressure of CO2 at the discharge of the gas cooler rather than let it go through the expansion valve “go down and dissipate into the universe.” Instead, the pressure exchanger recycles the high-pressure energy and then uses this energy to compress low-pressure CO2 vapor from the receiver into high pressure. Then, this high-pressure gas feeds into the intake of the gas cooler to complete the pressure exchanger cycle.

Thus the PX G1300 acts like a parallel compressor but does not require any energy. “So it is free compression due to which the main compressor’s workload is reduced, and electricity is saved,” he said.

“The higher the ambient temperature increases, the higher the energy savings.” Chen added.

“I think we have a great innovative product, and we are looking forward to many more PX G1300s to install.”

Stien Develtere, Purchaser at Fieuw Koeltechniek

“The higher the ambient temperature increases, the higher the energy savings.”

KC Chen, Vice President for CO2 at Energy Recovery

Author Saroj Thapa