Axiom Energy, a five-year-old company in Richmond, California (U.S.), that began as the provider of a “refrigeration battery” for supermarkets, is now beta testing a “virtual battery” driven by artificial intelligence (AI).
A Whole Foods Market and Walmart outlet in the U.S. are using the refrigeration battery, which overnight creates ice that is used during peak energy periods during the day, offsetting the refrigeration load.
The virtual battery takes the concept one step further as a software-only solution that operates as part of the “Axiom Cloud,” explained Amrit Robbins, CEO of Axiom Exergy. The system is simply “a computer inside a box on the wall that links to the refrigeration controls and sends data to the cloud.” The Axiom Cloud is being tested in the field in the U.S. in preparation for a formal release.
In a case study of a California store using the Axiom Cloud, the software runs the low-temperature compressors in the existing refrigeration system more often than normal between 9:30 am and 2 pm, thereby pre-cooling low-temperature display cases in preparation for a hot afternoon when peak demand is normally experienced.
Between 2 pm and 5:30 pm, the Axiom Cloud cycles individual compressors on and off as necessary to prevent “the building load from going above the forecasted optimal target of 230kW,” the case study says. Concurrently, the Axiom Cloud “opens and closes EPRs [evaporator pressure regulators] on individual cases to ensure that no case temperature drifts above its setpoint.” During a 15-minute period starting at 2:30 pm, Axiom Cloud significantly decreases the rack load to prevent “a demand spike that would have increased demand charges for the entire billing period.”
During an average summer month at the store, the retailer saves approximately $700 on demand charges, the case study says.
“We’re unlocking the thermal storage capacity of the existing low-temperature system,” said Robbins.
The Axiom Cloud also offers a “Virtual Technician” feature, which includes ongoing retrocommissioning and predictive maintenance.
Most refrigeration systems allow only the head and suction pressure to be adjusted while other elements, such as valve positions, compressor settings and fan settings, are fixed, Robbins noted. “With ongoing retrocommisioning we unlock those variables using an intelligent control strategy.”
The predictive maintenance function anticipates compressor, condenser and evaporator failures and refrigerant leaks before they occur, according to Axiom Exergy.
“We’re unlocking the thermal storage capacity of the existing low-temperature system.”Amrit Robbins, Axiom Exergy
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