Engineering tomorrow improves movie theater comfort and efficiency

Friday, October 9, 2015

Creating the best movie-going experience for film lovers is critical for a movie theater complex located north of Los Angeles in Universal City. Nineteen screens create an amazing movie-viewing experience, with digital surround sound and stadium-style rocker seats. Because comfort is so critical, the theater worked with Los Angeles-based Air Treatment Corporation to install a Multistack MagLev™ water-cooled centrifugal chiller that uses Danfoss Turbocor® oil-free, variable speed, magnetic bearing compressors to deliver reliable, efficient, precise temperature control under any conditions.

“The Multistack chiller looked like it would be a real efficient workhorse,” said the complex’s director of technical services. “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. The Multistack chiller proved to be a much smarter solution than the previous system.”

“The theater complex requires reliable, efficient cooling 365 days a year,” said Bruce Lumbattis, systems specialist for Air Treatment Corporation, who oversaw the project. “Nobody wants to refund tickets for uncomfortable customers. The old system was 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 6:00 a.m. During the night the system would build ice, and then melt it during the day to provide cooling to avoid peak demand charges for electricity.”

“But when the complex installed their own 12 KV switchgear to distribute power for a new solar photovoltaic (PV) array, it changed their 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.”

Multistack chiller brings sound and efficiency benefits

Lumbattis talked to an engineer about replacing the thermal storage system, which was configured with three 970- ton/hour thermal storage tanks and two screw compressors in a sub-basement. The chillers were connected by a six-inch discharge line and a 4 1/8-inch liquid line with two evaporative condensers on a roof 70 feet above the basement. The engineer suggested replacing the screw chillers with a standard, watercooled centrifugal chiller and replacing the evaporative condensers with cooling towers. Ten– or 12-inch diameter piping and pumps would circulate condenser water from the basement to the rooftop.

“I had just installed those evaporative condensers in 2006,” said Lumbattis. “They were in good shape. I suggested that we keep using them. Evaporative condensers in hot, dry climates like southern California deliver lower condensing temperatures, which can significantly reduce chiller energy consumption. I pointed out that Multistack offers a condenserless flooded centrifugal chiller design that could use the existing evaporative condensers. It would eliminate the need for a recirculation system using cooling tower, large piping, condenser water pumps and water treatment system.”

“We tore out the screw chillers and tanks, and installed a Multistack MS450FL MagLev™ water-cooled flooded chiller with 450-ton capacity at a 42-degree design leaving water temperature. It has revolutionized our operations. We gained an unbelievable amount of space in the mechanical room. And the chiller’s sound and efficiency benefits are the direct result of the Danfoss Turbocor®compressors.”

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