Gannett Fleming: Shippensburg University central utility plant design
Electrical, power; HVAC, mechanical; lighting; energy, sustainability; plumbing, piping.
Engineering firm: Gannett Fleming
2016 MEP Giants rank: 50
Project: Shippensburg University central utility plant design
Location: Shippensburg, Pa.
Building type: Educational facility
Project type: System overhaul (e.g., mechanical system upgrade, fire protection system overhaul, etc.)
Engineering services: Electrical, power; HVAC, mechanical; lighting; energy, sustainability; plumbing, piping
Project timeline: January 2011 to July 2015
MEP/FP budget: $31.9 million
Keeping students and faculty comfortable and safe while keeping costs low were central themes to Gannett Fleming’s development and implementation of a new central cooling plant for Shippensburg University in Pennsylvania. Work included the simultaneous decommissioning of an existing central heating plant and installation of a more efficient decentralized, clustered-heating-plant strategy. The work also included the coordination of the associated heating/cooling distribution piping systems. Throughout the 210-acre campus, 27 of the 55 buildings and 1.8 million sq ft (out of a total 2.4 million sq ft) of space were affected by the massive project.
Minimizing campus disruption was one of the most visible challenges addressed. To assure a safe environment for students, faculty, staff, and visitors, alternate routes were provided for any sidewalks or pathways that were temporarily closed and construction areas were clearly identified and fenced off for excavation work. The university’s operational calendar also demanded special consideration. To avoid interrupting staff and student schedules, and to take advantage of the heating and cooling seasons, the new infrastructure was designed to be constructed on a fully operational university campus. New heating boiler systems and underground heating hot-water and steam piping were installed during late spring and summer when classes were not in session. The new central chillers and chilled-water piping were installed during fall, winter, and spring without disruption to the class schedule.
Some portions of certain buildings had to be closed to allow for the demolition of existing steam-heating equipment and for the installation of new hot-water heating boilers, associated pumps, controls, and piping. This complicated the construction schedule and demanded a phased approach to temporarily relocate the existing systems in order to minimize service interruptions.
In all of the campus buildings with hot-water heat, the existing steam-to-water converters and associated equipment were removed and the existing building heating system was reconnected to the new distribution system piping. Additionally, seven campus buildings had never been converted from steam heat to hot water. To support these buildings, new steam boiler and distribution systems also were provided. Sequencing these activities was critical to the success of the project.
Another challenge involved upgrading the existing buried natural gas distribution system to allow for the added loads of gas-fired hot-water boilers, which replaced the antiquated coal-fired central steam plant and distribution piping. To meet this challenge, a new service connection to the campus grid was made and a new gas meter installed. In locations where additional pipe capacity was needed, parallel lines were run to minimize service downtime and construction costs. These new lines were sized with an eye to the future in anticipation of campus developments.
The team also took a creative approach when upgrading three buildings that were listed on the National Historic Registry, including Old Main. Gannett Fleming’s professionals successfully integrated the new infrastructure while complying with strict requirements set by the National Historic Registry.
Gannett Fleming’s innovative solutions resulted in the replacement of the more than 60-year-old coal-fueled steam-generation plant with a more efficient decentralized and uniquely clustered modular heating system, plus the addition of a new central chilled water cooling plant and underground distribution arrangement for the campus’s air conditioning needs. This new heating and cooling infrastructure maximizes thermal comfort for students and staff while significantly reducing energy consumption and limiting the environmental impact.
Before the new heating system was designed, Gannett Fleming compared the lifecycle costs of several design options and found that a 30-year lifecycle cost savings of $19.3 million could be realized by designing a decentralized heating system in lieu of a single central plant.
Now, clustered mini-heating plants with natural gas-fired boilers provide heat to most of the campus buildings. The 25 new boilers, located in seven new boiler-room locations, reduce the distance the heat needs to travel, which significantly decreases piping distribution costs and energy distribution losses as compared with the original central, coal-fired heating plant. Also, the boilers are high-efficiency and were designed with sufficient redundancy so that the loss of one boiler does not affect the system’s ability to meet space-heating needs.
The creative heating solution is already making an impact. For the 2014-2015 heating season, the campus’ energy utilization index decreased by more than 38.1% as compared with the previous 4 years.
Upgrades to the campus cooling systems also produced positive results. A new 3,000-ton high-efficiency cooling plant using variable primary-flow pumping and underground piping distribution now provides the majority of the campus cooling. To reduce on-peak demand cooling, a 1.7-million-gallon thermal energy storage tank was installed, which allows chilled water to be generated during off-peak hours, such as overnight, to provide up to 4 hours of full-load capacity without the need for mechanical cooling. Further, an existing 500-ton packaged air-cooled chiller was relocated adjacent to the new central plant to provide for low-load or winter operation and additional redundancy.
Comparing electrical consumption data during the 2014-2015 cooling season to the previous 4 years, the university realized a 12% reduction in kilowatt-hour consumption and a 14.8% reduction in demand—despite an 11% increase in cooling degree days.