New boilers improve energy efficiencies at Duke University
Duke University‘s commitment to sustainability continues with a $25 million renovation of its East Campus Steam Plant and conversion to natural gas boilers.
For about 50 years, the plant’s coal-fired boilers supplied steam through underground pipes and tunnels to heat campus buildings until the plant closed in 1978. The new plant, complete with 15 Miura LX series gas-fired steam boilers, will provide 35 percent more steam capacity to campus, while simultaneously helping to reduce the University’s environmental footprint.
The new gas boilers require less water and time to produce steam – and at lower emissions of greenhouse gases than coal. Instead of using lots of energy to fire up one to three large coal boilers, the plant can calibrate among 15 smaller gas boilers based on demand.
Miura boilers feature an exclusive “once-through” design, which turns water into steam in five minutes (or less) and provides high in-service operational efficiencies
“We can have them on cold standby and have them come on as necessary, which creates a significant reduction in the energy losses associated with a typical start-up, purge, and warm-up cycle of a boiler,” said Russell Thompson, director of utilities and engineering for Duke Facilities Management.
At full capacity, the 15 Miura boilers in the new East Campus Steam Plant will provide Duke with a 110,000 lb.-per-hour base load year-round, and perhaps up to about 130,000 lbs. during peak-need times.
In addition to their On-Demand Steam capability, Miura boilers also save, on average, as much as 20 percent annually on fuel costs over other boiler designs. Currently, Duke is still in the commissioning process, so data on fuel savings is not yet available.
Miura’s exclusive technology also produces BHP outputs comparable to much larger units, but with far less water consumption and a more compact footprint. This enabled Duke to install its 15 Miura boilers in the East Campus Steam Plant without having to expand any part of that historic brick building.
As a result of their energy-efficient “green” design, Miura boilers output reduced levels of harmful emissions such as carbon dioxide (CO2) and nitrogen oxide (NOx). Miura Boiler’s gas-fired/Low-NOx LX Series steam boilers are designed to eliminate 75 percent of the harmful emissions of standard gas-fired boilers. Miura Boiler’s LX Series steam boilers provide industry-leading reduced NOx emissions as low as 9 ppm (standard gas-fired boilers produce pollutants at a rate of 80 ppm).
“From a total production standpoint, we have gone from producing 95 percent of our steam with coal to producing 85 percent of our steam with natural gas,” Thompson added.
The steam plant conversion is part of Duke’s overall goal to become a climate-neutral campus, a commitment by President Richard Brodhead in 2007, as part of the American College & University Presidents Climate Commitment.
That reduced coal usage translates to a reduction of 30,000 metric tons of CO2. “It is our first big step in our Climate Commitment Challenge to reduce our carbon footprint,” Thompson said.
“This has been an important project from the standpoint of building a state-of-the-art system,” Thompson affirms. “It has also allowed us to preserve a very beautiful and historic campus building.”
The design team for the project consisted of RMF Engineers, Smith Group Architects, Thompson’s team from Duke University Utility and Engineering Services, and the Duke Office of Project Management. The construction team was led by the Balfour Beatty Corporation, and the main mechanical contractor was Boiler Masters Inc.