When North Carolina State University needed to update the Centennial Campus’ chilled water capacity without a costly plant expansion, it turned to Greenland Enterprises in Hampton, VA. The firm is known for its Design-Build expertise, and providing solutions for challenging and complex mechanical systems.
The $5.2M project involves building a new Thermal Energy Storage (TES) unit that holds roughly 3.5 million gallons of water in the 90-foot-tall structure. When operational, the storage tower will store 25,000 Ton-Hours of cooling capacity via chilled water, which is distributed during periods of high cooling demand. The system is “charged” during off-peak periods to reduce power demands and corresponding energy costs.
Technical Details: The TES consists of a field-erected steel tank that will charge and discharge through an octagonal piped or radial plate steel diffuser system. A stairway along the tank radius will provide operator access to side-mounted temperature transmitters and roof-mounted level transmitters.
The TES replaces the current plant primary-to-secondary bridge/de-coupler, so if the primary loop generates more flow than the secondary is consuming, excess flow charges the tank. In the reverse scenario, the tank will discharge. The charge/discharge rate is 12,000 GPM, or 6,000 Tons, at a 12-degree temperature differential.
When finished, the plant will be supported by Honeywell PLC controllers with a common graphics platform. TES field devices and sequencing will be incorporated along with guidance provisions for the condensing steam turbine generator for campus power demand reduction.