Chilled Water Systems
The University has one of the most sophisticated chilled water generating systems in the world. Chilled water, which is used to cool buildings and equipment, is provided either by the District Cooling Systems comprised of a network of chiller plants and underground piping, or by stand alone chillers dedicated to individual buildings.
The main campus district cooling system consists of five chiller plants with a combined capacity of 50,000 tons. The plants are interconnected by underground piping and operated as one production system using a networked Supervisory Control and Data Acquisition (SCADA) system. From a single console, operators can manage and balance loads among the chiller plants, use capacity anywhere in the system, and continue operating in critical areas despite cooling equipment failure or utility outages. Two of the chiller plants house both steam absorption and electric centrifugal chillers; the other three house only electric centrifugal chillers, allowing Chilled Water Systems to quickly respond to outages of either energy source, as well as manage costs by monitoring the local electric utility’s hourly pricing program. The Operations Center also includes a 5 million gallon stratified cold water storage tank. The thermal storage system shifts a portion of the University’s chilled water production to off peak periods, reducing the need for electric purchases from Duke Energy during peak times.
After it is chilled, the water flows into a loop piping system, which distributes the water to bridge interface systems that control the flow of chilled water in and out of each of the campus buildings. These bridge interface systems ensure the buildings receive and efficiently use the chilled water to meet their cooling demand. The distribution system can pump up to 100,000 gallons of chilled water per minute through more than 22 miles of underground piping and 150 individual building bridge systems. When the water has been used (warmed), it is returned to a chiller plant to be chilled again.
Link to FPC for CW Capital Projects and Status
Link to CW Design Standards Document
