Against the Grain (ATG), a producer of gluten- and grain-free pizzas, bagels and breads, uses cold storage facilities to distribute frozen foods to food retailers throughout the country. At any given moment, their walk-in freezers are stocked with gluten-free pizzas and frozen inventory worth millions of dollars.

Operating in Vermont provides opportunities to participate in the state’s advanced energy management programs, which are helping to balance renewable energy resources and peak electricity demands. ATG had been engaged in a flexible load management (FLM) program with local utility, Green Mountain Power, primarily leveraging the factory’s HVAC system in dynamic demand response events.

During a refrigeration system tune-up, service technicians and energy management stakeholders explored the potential to add cold storage refrigeration to an existing FLM program. Doing so would require a robust refrigeration controls architecture, capable of providing grid interactivity while maintaining refrigeration reliability.

In late 2023, three walk-in freezers were targeted as test assets for a proof-of-concept pilot. The pilot brought together multiple organizations:

• Copeland: The provider of E3 supervisory control and Copeland Load Management grid interactivity app, with expertise in leveraging refrigeration in demand response programs.
• Dynamic Organics: A smart grid software solutions company providing FLM platforms.
• Turner Piping and Refrigeration: An energy, HVAC and refrigeration contractor/servicing company.
• VEIC: A national clean energy nonprofit that delivers high-impact energy solutions focused on equity and innovation.
• Efficiency Vermont: A statewide energy efficiency utility operated by VEIC, clean energy and energy management consultants.

Shedding Power & Quality Concerns

Although refrigeration systems are among the most energy-intensive equipment in cold storage facilities, operators have been reluctant to include them in demand response programs, because of food safety and quality concerns. For Against the Grain to add cold storage to its existing FLM program, it would need assurance that its perishables were not at risk.

The existing refrigeration system was still operating using an original mechanical controls architecture. Not only would an upgrade be needed to enable grid interactivity and manage demand response events, but it would also need to provide remote visibility to freezer status, setpoints and alarms.

From a power generation or grid-interactivity perspective, many utilities are simply unaware that technologies and safeguards exist to leverage refrigeration in demand response programs. However, with proper controls in place, both retail refrigeration — such as medium-temperature cases and walk-in coolers — and cold storage systems can be included in these programs.

“Due to the existing thermal mass of frozen product, we’re exploring the built-in potential for demand response in cold storage facilities,” said Corey Wheat, business development manager for energy and utility solutions at Copeland.

As part of the refrigeration overhaul, upgrading the freezers from traditional mechanical controls to a modern Copeland controls architecture was necessary, including the E3 and Site Supervisor controls, and the CC200 case controller.

In particular, the E3 supervisory control and Copeland Load Management app were essential to enabling demand response capabilities in the refrigeration pilot program.

The E3 provided visibility to refrigeration assets and alarms via remote monitoring, while anchoring the FLM program with its ability to adjust setpoints based on demand response events.

Dynamic Organics spearheaded the integration of refrigeration assets into the existing FLM program, which was previously enabled for HVAC only.

“Once we got communication dialed in between the Copeland app and our software, we could start exploring load shedding opportunities for the freezers,” said Cody Druschel, master systems integrator at Dynamic Organics.

The cold storage load shedding solution was based on a pre-cooling and coast model. During the pre-cooling period when the utility has a high availability of solar power, setpoints were lowered to pre-cool the product. Then, during the utility’s peak demand period, setpoints were raised above the baseline, essentially resting the refrigeration assets and coasting on the stored energy of the frozen product’s thermal mass.

Once the utility’s peak demand period ended, the refrigeration would return to its normal setpoint operation.

Throughout each phase, the E3’s Copeland Load Management app controls the refrigeration setpoint changes: pre-cooling, load shedding and stabilization. Dynamic Organic’s grid-edge controller integrates with both the Against the Grain HVAC management system and the Copeland E3, for monitoring and control of these distributed resources to grid operators like Green Mountain Power.

To maintain food quality standards, the team conducted significant testing on the impacts of setpoint changes.

In addition to the setpoint changes, the E3 enabled them to strategically coordinate defrost cycles with the FLM program.  

Energy & Cost Savings

Participation in the FLM program drove rate-based benefits from the utility provider to Against the Grain. The more they participated, the more their rates/charges were lowered. The cold storage pilot proved that the two primary goals of the program were achieved:

1. Lowering energy consumption during peak periods.
2. Maintaining reliable refrigeration throughout demand response events.

The E3 provided a level of assurance to add cold storage to the FLM program without compromising Against the Grain’s food quality standards.

“Because frozen foods offer more thermal mass, we’ve shown that we can be even more aggressive with extended load shedding periods,” Wheat said.

This cold storage pilot program represented a proof of concept for retailers, producers and utilities seeking to validate the potential of shedding energy loads in refrigeration.