Challenge
Seeking to build a new energy plant to serve the athletics buildings on its West Campus, Clemson University outlined its criteria. In addition to providing a comfortable environment for students and staff, the University wished to make the energy plant reliable and as efficient as possible to adhere to its commitment to sustainability.
Solution
Responding to a Request for Proposal, Trane submitted a design/build solution and assembled a team of highly qualified professionals familiar with Clemson University and its processes. Ultimately, the Trane team was selected for the energy plant project.
Tailoring design to site usage
In collaboration, Clemson, Trane and designers worked to create a facility tailored to the university's needs and the construction site parameters. Not wishing to detract from weekend tailgating activities or dominate the skyline with a metal structure, the design team capitalized on the area’s terrain, with the cooling towers cut back into the hilly slope and the building in front to shield the towers from view.
Providing a single source of accountability
With expertise to design a complex chilled water system, as well as talent to execute its construction, Trane delivered a clear single point of contact for project leadership and accountability, yet provided a conduit for a collaborative approach by a select group of seasoned local designers, general contractor, and subcontractors. A project manager was assigned to oversee all details to resolve issues, maintain commitments, manage scope and schedules, control costs, and assure quality. Having a single source for project delivery enabled the university to reduce cost, scheduling issues, and project changes, while promoting design innovation.
Creating standardization and redundancy
The plant design supports two identical 1,500 ton Trane® CenTraVac™ centrifugal chillers, with site expansion available to 12,000 tons. The chillers have a common return water temperature, control to the same leaving set point, and are equally loaded, helping to simplify plant operations. Chiller pumps and condenser pumps are manifold with identical flow through each operating evaporator and condenser. Identical components and operating characteristics result in a higher degree of redundancy; lower the statistical probability of failure; create space, clearance, and access efficiencies, and standardization of parts and maintenance procedures; and enable plant operators to more easily detect issues.
Optimizing operations
Chiller-tower optimization strategies were implemented to reduce overall energy consumption. Cooling tower temperature set points were dynamically reset, and all chillers were adjusted to respond the same to changes in primary or condenser water flow. Condenser water headers in the chiller plant allow multiple tower cells to be used with operating chillers. The plant operates down to minimum flows based on the number of cells or chillers in operation. Proprietary controls strategies simultaneously adjust tower fan speed and condenser water pump speeds to reduce plant energy use.
Driving efficiency and sustainability
Rugged, yet simple in design, Trane® CenTraVac™ chillers provide the industry’s highest full- and part-load efficiencies. Built without failure-prone, speed-increasing gears that require constant maintenance, the direct-drive, centrifugal chillers provide quiet, vibration-free operation. The chiller’s semihermetic motor design, along with low-pressure refrigerant, result in an ultra-low refrigerant emission rate of less than 0.5 percent annually, and assure clean, cool operation. Adaptive Frequency™ Drives (AFD) control the operating speed of the chiller compressor motor by regulating output voltage in proportion to frequency. Varying the speed to optimize compressor performance can significantly reduce energy use.
Taking command of plant performance
Tracer AdaptiView™ chiller controls enable building operators to take command of the chiller plant, using a full-color touch screen display and interactive animated graphics to view, access and control chiller operations and functions, and gain insight into the operating patterns, energy use and system performance. Algorithms embedded within the controller work with the unique capabilities of the CenTraVac chiller to keep buildings operational, even during challenging conditions.
Improving satisfaction
To increase manager satisfaction and ability to operate the complex plant, Trane held training sessions at start-up, and three and six months after start-up, with an additional forty hours to be scheduled at a later date. Focused on startup, shutdown, operation and maintenance requirements, troubleshooting, the comprehensive training covers chiller sequencing, Trane AdaptiView touch screen interface, VFDs, advanced chiller diagnostics, control panel data, cooling towers, and system optimization.
Results
Efficient design and construction methods employed by the Trane team and extensive collaboration with Clemson University personnel delivered a modern high quality chiller plant ready to serve the University with plant space to accommodate future campus growth. The complex design/build project was completed within the established budget and 270-day construction period.