New boilers increase energy efficiency, reliability at NC State

Inside the newly-renovated Yarbrough Steam Plant, which features new, more-efficient boilers.
Inside the newly-renovated Yarbrough Drive Steam Plant, which features new, more-efficient boilers.

Energy will be supplied to NC State University buildings more reliably and efficiently thanks to the completion of a major boiler upgrade at Yarbrough Drive Steam Plant, where existing boilers installed as early as 1949 were replaced.

After nearly 18 months of construction, two new 100,000 pound-per-hour boilers replaced two 50,000 pound-per-hour boilers to double capacity and improve efficiency from 68 percent to 82 percent.

“It was definitely an efficiency improvement and enables us to keep up with campus demand. We always want to have more steam capacity on standby than what full campus load would demand. So if we have one boiler down, we’re still able to maintain and provide reliable and cost-efficient steam production to campus,” said Bill Ferrell, a plant engineer at the Yarbrough facility.

The final phase in a $61 million energy performance contract, the Yarbrough upgrades add to the efficiency increases at the university’s Cates Avenue Steam Plant, where cogeneration technology was added in 2012 to enable the university to capture wasted exhaust heat and convert it to steam. Steam is used as the primary heating source for the majority of buildings on main campus.

In addition to efficiency increases, the new natural gas-powered boilers use No. 2 fuel oil as a backup fuel supply, which burns cleaner and operates more easily than the No. 6 fuel oil used by the old boilers. This alternate fuel supply is used during curtailment periods when suppliers divert limited natural gas supply from NC State in order to meet the demands of other customers.

What other color than Wolfpack red would NC State choose for its new, high-efficiency boilers?
What other color than Wolfpack red would NC State choose for its new, high-efficiency boilers?

The renovation also included refurbishing the plant’s last existing boiler and installing new auxiliary equipment throughout the plant, which was built in the 1920s.

“Now the entire system is running more efficiently and is easier to operate,” Ferrell said.

The renovation is expected to earn designation for Leadership in Energy and Environmental Design (LEED) certification at the silver level for efforts such as an approximately 80 percent recycling rate of steel and other demolition debris, efficiency improvements and use of sustainable building materials.

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