New tank helps keep campus, and the planet, a little cooler

People inside the tank

Tucked into a corner of north campus lies a sophisticated system for heating and cooling the main campus, including a new, energy-saving water tank.

The complicated, multilevel buildings that house the central power plant feed a labyrinthine system of steam pipes, chilled water pipes and electrical systems responsible for keeping campus buildings comfortable, as well as providing the necessary climate controls for various UO labs, libraries and museums.

The utilities and energy team in Campus Planning and Facilities Management is in the midst of a multifaceted project to optimize and enhance cooling systems for campus. Those actions will increase the efficiency of campus cooling, protecting UO assets and leading to modest reductions in both costs and carbon emissions.

Tank exteriorThe biggest change is the new water tank, which will be used to cool campus during peak summer usage. The tank, a sage green behemoth hunkered west of the power plant, holds 3 million gallons of water and features a relatively simple design for transferring that cooled water to campus to meet the UO’s air conditioning needs.

Building the tank is one commitment from the university’s current Climate Action Plan and will reduce carbon emissions in a few ways.

First, the tank’s water will be re-cooled overnight, saving the university a modest amount of both energy and carbon emissions.

Second, nighttime electricity in the Pacific Northwest tends to be less carbon-intensive than electricity generated during the day because of the daytime need to use gas-powered turbines or purchase carbon-intensive electricity to meet consumer demand.

Last, conventional chillers require refrigerants that are hundreds of times more potent than carbon dioxide if leaks or other issues lead to their release into the atmosphere. The thermal tank provides chilling equal to two conventional chillers without requiring additional refrigerants. Using the tank also reduces the use of the UO’s existing chillers, thereby preserving those assets longer and providing a crucial backup for the hottest days. 

Other actions from the project include upgrading the chiller pumps by adding “variable frequency drives,” adding more cooling plates to the free cooling heat exchanger for campus’ winter months, upgrading the cooling tower basin heaters that prevent water from freezing, and improving the control system to increase the efficiency of plant operations overall. The goal is to have the changes operational in time for the summer heat.

While the effects of each of the upgrades alone may not seem like much, they add up when combined.

“We are hoping to see a megawatt’s worth of reduction to the electrical load during the summer months,” said Paul Langley, interim co-director of utilities and energy. “We do have a learning curve for us with this project, but we’re optimistic about the impacts it will have on campus energy efficiency.”

Rick Tabor, the other interim co-director of utilities and energy, underscores the value of small changes.

“Conservation is a big part of decarbonization, and that’s one way the campus community can get involved in supporting these efforts,” he said. “Using less power, water, heat, etc. draws less on these campus systems. Small, incremental changes on campus make a big difference in the plant.”

—By Sarah Stoeckl, Office of Sustainability