Full Steam Ahead for Sustainable Power Plant
An innovative restoration turns a historic but inoperable coal-burning steam plant into a modern, energy-efficient marvel at Duke University.
As recently as 2008, Duke University’s East Campus steam plant was an overgrown ruin. The former coal-burning plant had been shuttered for more than 30 years, it was covered in vines, and its roof had turned into a forest. Plant roots tore away at the 80-year-old brick façade, in some cases boring right through the 30-inch-thick walls, cracking them and shifting them out of plane and causing massive damage.
Despite these problems, the university saw value in repurposing the historic facility, and in June 2008, an $18.9 million sustainable renovation began that transformed the 6,341-sf building into a modern, efficient natural gas-burning steam facility. Duke engaged the Building Team of SmithGroup (architect), RMF Engineering (MEP), and Balfour Beatty (GC) to tackle the project, which is seeking LEED Gold.
The plant’s defunct coal-burning equipment was replaced by 15 energy-efficient Miura boilers, specifically chosen because their modular nature allowed them to be squeezed into the existing space better than traditional fire-tube and water-tube boilers. Even so, the Building Team had to construct a mezzanine to allow the new boilers to be stacked vertically. The Miura boilers produce steam much faster than traditional boilers, with a cold-to-steaming rate of less than five minutes, which reduces energy loss associated with startup, purge, and warm-up cycles. The boilers also have a factory-installed feedwater economizer that minimizes waste heat through the flue gas, increasing boiler efficiency by about 5%.
To further increase efficiency, the Building Team incorporated a blowdown heat recovery system that aids water savings by eliminating use of cooling water to temper the blowdown before it enters the sewer system. The coal-to-gas conversion helped Duke reduce its coal consumption by 70%. The facility itself operates 33% more efficiently than a baseline building.
As for the crumbling plant itself, the Building Team took on the restoration of the 1928 facility, which was designed by Horace Trumbauer, the architect behind numerous buildings on the Duke University campus.
Damage caused by years of neglect was remedied by rebuilding areas where masonry couldn’t be repaired, then cleaning and repointing brick that could be saved. A new cast-in-place roof deck was installed, along with a high-albedo, single-ply roof membrane. The building’s existing steel windows could not be salvaged, so they were replaced with new steel units that matched the profile of the originals. Low-e glazing was used on windows in the plant’s conditioned spaces; these same spaces were also insulated for greater efficiency. An old railroad trestle, which at one time brought coal cars up to the roof of the steam plant, was restored and the existing rooftop steel coal shed was rebuilt with corrugated fiberglass panels; now the coal shed glows at night.
In total, the Building Team was able to reuse 90% of the existing facility and diverted 85% of construction waste from landfills, a strong indication of the Building Team’s concerted effort to reuse or repurpose as much existing material as possible. For example, the original coal chutes were reused as part of the plant’s ventilation system; an old deaerator tank was put to use as a rainwater storage tank (rainwater is used within the plant to flush toilets); and old valves and wood floor decking were used to build benches for the terrace. Items that weren’t reused were donated to campus and community arts groups.
The project’s imaginative reuse of old elements and the careful addition of new ones caught the attention of our Reconstruction Awards judges. “It’s so carefully thought out,” said Walker Johnson, principal of Chicago-based Johnson Lasky Architects and honorary chair of the awards panel. “It’s absolutely one of the most unique projects,” said Darlene Ebel, Director of Facility Information Management at the University of Illinois at Chicago.
Summing up the judges’ reaction, George Tuhowski, Director of Sustainability for Leopardo Construction, Hoffman Estates, Ill., said: “They maintained a university icon. It’s functional, but it’s also a showpiece.” BD+C
Submitting firm: SmithGroup (architect)
Owner: Duke University
CM: Balfour Beatty
MEP: RMF Engineering
Size: 6,341 gsf
Construction cost: $18.91 million
Construction time: June 2008 to July 2010
Delivery method: CM at risk