For years, a movie-theater complex in Universal City, Calif., relied on a massive thermal-storage system using two large screw compressors.
“It initially made sense to use a thermal-storage system because, at that time, Southern California Edison provided incentives to use electricity during the off-peak hours of midnight to 6 a.m.,” Bruce Lumbattis, systems specialist for Los Angeles-based Air Treatment Corp., said. “During the night, the system would build ice and then melt it during the day to provide cooling to avoid paying peak demand charges for electricity.”
When the complex installed its own 12-KV switchgear to distribute power for a new solar photovoltaic array, it changed its operating plan.
“They were no longer dependent on the local utility for 480-VAC power and could generate their own electricity, so peak charges were no longer an issue,” Lumbattis said.
The complex’s director of technical services added: “We needed something that would perform over a wide range of loads, as they vary during the day and week. We were looking for problem-free performance—a system that runs perfectly—plus a control system that takes care of the chiller and corrects any problems out in the system.”
As detailed in this article on ContractingBusiness.com, the solution was a Multistack MagLev water-cooled centrifugal chiller that uses Danfoss Turbocor oil-free, variable-speed, magnetic-bearing compressors.