Duke University’s commitment to sustainability continues with a $25 million renovation of its East Campus Steam Plant and conversion to natural gas boilers. The educational institution installed 15 boilers from Atlanta-based Miura Boiler to achieve high-capacity steam output, automated operation, compact equipment footprint with reduced fuel consumption, lower emissions and other “green” benefits.
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 with 15 Miura LX series gas-fired steam boilers will provide 35 percent more steam capacity to campus. The new gas boilers require less water and time to produce steam, and do so at lower emissions of greenhouse gases than coal. Instead of firing up one to three large coal boilers, the plant can calibrate among 15 smaller gas boilers based on demand. Miura boilers have a once-through design that 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 startup, purge and warmup cycle of a boiler,” says 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 the Durham, N.C.-based university with a 110,000 lb/hr base load year-round and up to approximately 130,000 lb/hr during peak-need times.
According to the manufacturer, Miura boilers output reduced levels of emissions such as carbon dioxide (CO2) and nitrogen oxide (NOX). Miura Boiler's gas-fired LX Series steam boilers provide NOXemissions as low as 9 ppm, in comparison to standard gas-fired boilers, which produce pollutants at a rate of 80 ppm, says Miura.
“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 says.
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.
Miura's consume less water and offer a more compact footprint that alternate designs, says the manufacturer. 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. “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.”