Maximum Power

By K. Robert Wendel

Power plants aren't known for their aesthetics or high design, but Arizona State University's new Sun Devil Energy Center is changing that.

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Since the cogeneration project is in a high profile position between the new bio science complex and the McAllister Village Complex, architects and builders are creating a signature building with its own distinctive architectural vocabulary.

The challenge was to construct a building that could contain the noise and vibration of motors, pumps and chillers while creating an exceptional piece of architecture that fits in with the campus' design.

"Normally cogeneration facilities are tucked away but this building plays an integral role in the urban master plan of the campus," said architect Jay Silverberg of the Phoenix office of Gould Evans. "The challenge was to control the sound and create a wrapper for the building, but with something that was artful and beautiful and changes peoples' perception of what a cogeneration plant looks like. The university was looking for something that would be an icon and architecturally exciting."

The 73,000-sq.-ft. project is two stories above grade with a basement and engages pedestrians with a covered breezeway that connects the new McAllister Village complex with the rest of the campus. The project is also likely the first cogeneration plant that includes classrooms.

"We wanted to be more than just a power plant," said Kevin Nissley, a project manager with APS Energy Services, which is partnering in the project with ASU and Northwind. "We wanted to have a place where future engineers can see first hand how these things work."

Work on the project's first phase started in September 2004 with plans calling for the construction of a $44 million cast-in-place concrete structure with walls ranging from 2-ft. to 4-ft. thick. Initially, the project calls for three chillers totaling 6,000 tons of cooling, a 12kV electrical distribution panel and a cogeneration system.

"The intent was to get those three chillers on line because the research labs are coming online and they need that extra capacity," said Roger Gaske, southwest manager for mechanical contractor Kinetic Systems Inc. of Phoenix. "Phase one is designed so that when you bring in future chillers, all you have to do is hook up a pipe and open a valve."

A second phase, which will start in October, adds another cogeneration system, nine more chillers and a gas turbine that will produce 8 mW of power. There will also be a heat recovery steam generator that will supply steam and hot water and two back-up diesel generators. When the project is completed, two five-cell cooling towers will be needed.

"The heat recovery steam generator is a massive piece of equipment, so the structural requirements are really complicated," said project manager Mike Horn of the Phoenix office of McCarthy Building Cos.

"This thing is pretty much a fortress. If the bombs start falling, this is where you want to be."

Since the building is so heavy and because of the poor soils, half of the building sits on drilled caissons, with the other lighter section resting on hard rock approximately 20 ft. below grade. Contractors poured more than 6,000 cu. yds of concrete, including 90 cu. yds. for one just 40-ft. long wall. McCarthy self performed the cast-in -place concrete work.

"The vibration of the pumps in the basement was our biggest problem," said mechanical engineer Quincy Love of the Phoenix office of Stanley Consultants. "We had to put those pumps on some of the biggest inertia pads I have ever seen."

In addition to the cast-in-place concrete, crews from Phoenix-based Coreslab Structures Arizona Inc. are casting hundreds of 45-ft. tall, 9-ft. wide concrete panels of various thicknesses that are cantilevered off of a steel frame, creating a 3-ft. space between the panels and the building. The space allows for extra cooling while the panels become the architectural detailing.

"Basically, we manipulate each single pattern in a way that is almost in Origami fashion," Silverberg said. "It really plays up the quality of light and shadow."