Whole Foods Installs Thermal Refrigeration Battery

A Whole Foods Market store in Los Altos, Calif., has received the first installation of Axiom Exergy’s thermal energy storage solution, the Refrigeration Battery. According to Richmond, Calif.-based Axiom, “The project successfully demonstrates the viability and potential of [our] energy storage solution by shifting up to 1,040 kilowatt-hours of electricity load at the facility for up to 10 hours a day over the course of several months,” without any changes to staff behavior or daily operations.

Whole Foods facility managers now get real-time information on the system’s performance via Axiom’s integrated cloud-monitoring platform, which includes enterprise-level monitoring and analytics, historical data, and real-time key performance indicators such as kilowatt-hours shifted, peak kilowatts reduced, and battery charge level.

“We are proud to be leading our industry by being the first to use such an innovative technology to shift our large refrigeration-based energy loads to off-peak hours,” said Tristam Coffin, director of sustainability and facilities at Austin, Texas-based Whole Foods, which he noted “has a reputation for piloting and implementing sustainable solutions that also improve facility operations. This pilot is consistent with these efforts.”

Refrigeration accounts for as much as 55 percent of an average supermarket’s electricity consumption. By shifting electricity demand to off-peak hours, supermarket owners can avail themselves of lower nighttime rates to lower a store’s costly on-peak electricity demand by up to 40 percent.

“The Refrigeration Battery is no longer a concept, it is a commercial reality,” said Axiom President and co-founder Amrit Robbins. “By deploying the Refrigeration Battery, businesses can convert power-hungry refrigeration systems into intelligent assets that can respond dynamically to the needs of the facility and the grid operator, taking into account energy prices, weather patterns and grid programs like demand response.”

The installation was done as a passive retrofit, without modification of the existing refrigeration system or reprogramming of controls. The Axiom system integrator went in the facility’s mechanical room, next to the compressor racks, while the thermal storage tanks were placed in the loading-dock area behind the store. By using the store’s existing refrigeration system, the Refrigeration Battery stores “cooling” at night by freezing tanks of salt water when energy costs are low. Then, when electricity prices peak in the afternoon, the battery “discharges” to provide uninterrupted cooling services. The technology has an estimated lifespan of 25 years.

“Given the unique shape of a supermarket’s demand profile, which is relatively flat compared with other commercial buildings, Whole Foods Market needed a cost-effective energy storage solution capable of providing long-duration load shifting, as opposed to peak shaving typically provided by electrochemical systems,” explained Axiom Chief Technical Officer and co-founder Anthony Diamond. “By demonstrating consistent, daily electricity load-shifting, the Whole Foods Market installation marks an industry first and game-changer for facilities with large refrigeration-based energy loads.”

Additionally, Bentonville, Ark.-based Walmart has selected the Refrigeration Battery for installation at a store in Escondido, Calif.

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