Chilled Water Plant

Newer Chillers Lower Temps and Costs

The University of Iowa maintains a system of four chilled water plants and associated distribution piping. This system supplies all the buildings on campus with chilled water for space and process cooling purposes.

One of these plants, the North Campus Chilled Water Plant, which serves the east side of the campus, housed four chillers prior to 2021, three of which were at or beyond the end of their useful service life. Due to the degradation of the existing chillers, it has been necessary to deploy and operate two temporary chillers on Jefferson Street, next to Stuit Hall, to satisfy chilled water demand during the warmer months. This has added, on average, $320,000 to the facilities’ annual operating costs over the past two years.

This project will replace these three chillers — and the temporary chillers — with a single high-capacity (5000-ton) chiller. It will also upgrade the design of the piping infrastructure to respond more efficiently to variability in the demand for chilled water. The new design is also more resilient, such that the system can continue to provide cooling to all the buildings it serves, even if the largest chiller on campus is out of service. Slated for completion by the spring of 2022, the new system will ensure adequate cooling to the buildings for the next 25 years. Anticipating further campus expansion, the University of Iowa Energy Collaborative plans to replace the remaining North Plant chiller with another 5,000-ton unit in the next several years.

Management of the project involves elaborate planning and engineering workarounds to minimize disruption to building occupants. For example, many science laboratories on campus must maintain finely controlled temperature environments for housed animals or the operation of precision equipment. To ensure continuous cooling service throughout the project, a system of temporary chillers and piping was installed and calibrated to meet their needs, even during peak-weather periods.

In other buildings, such as the Iowa Advanced Technology Laboratories (IATL), highly sensitive instruments are affected by vibrations from demolition and other construction activities. By cooperating closely and maintaining ongoing communication with the affected stakeholders, the project team has been able to modify its work schedule and operations to limit vibrations.