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Vol. 25, No. 2, April 2006
California utilities test peak-shifting cooling technology
officials with Ice Bear unit
From left: Al Summerall and Randy Zwetig of Ice Energy Co., join Glendale Water & Power Director Ignacio Troncoso, GWP Business Representative Hector Gutierrez and Scot Hicks of Ice Energy Co., to launch the Ice Bear pilot project. (Photo by Glendale Water & Power)

California’s efforts to shave the state’s peak demand may get some help from an innovative ice-based energy storage unit Southern California Public Power Authority is testing in partnership with 11 of its member utilities.

The Ice Bear, manufactured by Ice Energy, LLC, can be used to expand an air conditioner’s capacity, or perform load-shifting, as it does in the SCPPA demonstration. The system makes and stores ice during off-peak hours using a building’s existing air conditioning system. The following day, a 100-watt pump circulates ice-condensed refrigerant to cool the building during peak hours, when demand is high.

“The pump’s motor is small compared to the compressor a conventional air conditioner would use to cool, so our kWh demand is lower, too,” said Hector Gutierrez, a business account representative for Glendale Water & Power.

Unit tested in different applications, climates

chiller's ice maker
The Ice Bear's ice maker is the key to shifting electricity demand. It makes ice with off-peak power, and uses it to cool during the day when electricity demand for air conditioning is at its highest. (Photo by Glendale Water & Power)

Gutierrez coordinated GWP’s participation in the project. The utility installed two units—one at the Glendale Sports Complex and a second at the Casa Verdugo Library. The cities of Anaheim, Azusa, Burbank, Los Angeles, Pasadena and Riverside and Imperial Irrigation District are also participating in the demonstration.

Burbank and Anaheim installed Ice Bears at city fire stations, and Los Angeles put units into a restaurant and a senior center. "We were looking for buildings with diverse applications," explained Ice Energy Vice President Randy Zwetzig. "Because SCPPA covers such a large territory, the units were spread across a good cross section of climate zones, too."

Both the sports complex and the library have five-ton air conditioning systems, and are open seven days a week. The Ice Bear is sized to offset the load from five- to 10-ton cooling systems. "Conventional TES systems are water-based and designed for buildings of more than 200,000 square feet. Usually, they are custom built," said Zwetzig. "Ice Bear 50 is refrigerant-based, which is less expensive to implement and suited to smaller applications."

Ice Energy installed the systems, but licensed HVAC contractors can install a new unit or retrofit using industry standard practices and conventional tools. Burbank reported completing the fire station retrofit in two days. “It’s easy to adapt the Ice Bear to conventional HVAC equipment,” said Gutierrez. “The icemaker is the only additional part.”

Maintenance is routine, he added. "Just check the water level once a year, and the manufacturer suggests adding tablets to prevent mineral buildup. No need for special training."

Peak shifting benefits customers

SCPPA provided $100,000 to purchase and install the systems. Funding came from California’s public benefit charge to support technologies that promote efficient use, storage, management or distributed generation of electricity.

According to the California Energy Commission, air conditioners consume up to 70 percent of the state's electricity on hot summer days. A technology that can shift that load from on-peak to off-peak hours can lower costs to customers, observed SCPPA Executive Director Bill Carnahan. “It’s cheaper to save a kilowatt of power than build a power plant to produce a kilowatt,” Carnahan said. “Ice Energy didn’t have to do a lot of convincing for us to give it the go-ahead.”

SCPPA is working with its members to monitor the system’s performance, and so far, the Ice Bear is “performing as expected.” Anaheim ’s preliminary results showed a 95-percent reduction in the fire station’s peak demand, and Gutierrez reported that the unit at the sports complex is on track to deliver comparable savings.

Zwetzig said that several SCPPA members are considering rate structure incentives for the Ice Bear and looking at wider deployment to key accounts. If the demand-side management tool can help utilities tame their unruly air conditioning loads, the Ice Bear may just become California's new state animal.

 

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