Steam-Plant Conversion Generates Cool Savings
June 6, 2014
Like many institutional and commercial facilities around the country, Mississippi State University
faced growing utility costs in the mid-2000s that forced maintenance and engineering managers to find new ways to do more with less.
In 2006, the university, located in Starkville, set a goal to reduce its energy consumption by 30 percent per square foot by 2016. So far, so good. The university has saved more than $25 million in electricity and natural gas and is well on its way to reaching its goal. The success has resulted from a series of retrofit projects — most notably, converting its central steam plant to high-efficiency, hot-water-condensing units.
"It's been pretty well documented that doing these types of things over time definitely impacts your bottom line," says J.D. Hardy, the university's associate director of utilities and an energy and mechanical engineer in facilities management in 2008, when the project started. "The cost avoidance is energy we would have otherwise spent if we had not taken the initiative to implement these changes and operate more effectively."
The first and most significant step the university took to reduce its HVAC-related energy costs involved the multi-million dollar conversion of the central steam plant. The plant served for years as the primary heat provider to almost 40 campus facilities with about 3.5 million square feet of space.
"Our steam plant was built in the mid-1920s and has a long history of providing heating and steam needs for the campus," Hardy says. "(The plant's) reached out with steam distribution through tunnels across campus, and with that type of distribution, there have been a lot of advances made. Over time, a system like that can become quite inefficient, even with the best maintenance practices."
The university replaced two steam boilers with 14 condensing, high-efficiency boilers. The old boilers operated at about 80 percent efficiency, while the new units operate at Btu ratings in the mid-90s. The university experienced a dramatic reduction in Btu per square foot since the new boilers were installed, lowering its electric and natural gas consumption from 162,000 Btu per square foot in 2006 to 102,000 by 2012.