Utah State University is in the final phase of installing a large thermal energy storage tank that is expected to save the school more than $100,000 annually.
On Tuesday afternoon, several USU officials climbed from the surface of the Health, Physical Education and Recreation field down the ladder to view the inside of the new water tank that has been placed. Inside is the diffuser piping that allows chilled water to be inserted and removed from the tank at very low velocities.
The top of the TES tank, which is 30 feet deep and 115 feet in diameter, is still visible while on the HPER field. The concrete tank will be completely buried below the field, where it will hold approximately 2 million gallons of water that will be used to cool buildings on campus.
The tank will be filled next week. Then, the entire hole will be filled in and another contractor will begin work on the Legacy Multi-purpose Fields, scheduled to be completed by August.
“It’s definitely been a big undertaking,” said Lorin Mortensen, a mechanical engineer for USU facilities planning design and construction. “We’re excited to be able to use the TES tank and take advantage of it. It will be a real asset to the university.”
The completion of the TES tank wraps up an effort that took a little over a year to complete, starting in February 2011.
Students, faculty and passers-by on 800 East might have noticed a massive hole in the HPER field, a mountain of gravel and dozens of construction crew workers for most of the past year. The project was expected to be done in December, but it ran behind schedule because of the weather.
“The project has definitely displaced the people that use the HPER field, so it’s been a big inconvenience,” Mortensen said.
USU invested $2.6 million into the construction and installation of the tank. The TES tank is designed to last for 40 years or longer. The project is funded by utility savings and building chilled-water connection fees.
Water in the tank is cooled using electric chillers during the most efficient time of the day, which is usually at night when the temperature is lower. The chilled water is then stored for use during warmer parts of the day. When air conditioning is needed, water runs through pipes in the existing underground tunnels, which lead to nearly every building on campus. Once it reaches the buildings, the water is sent through a coil system, where blowing air provides air conditioning.
The tank holds enough water to provide air conditioning for about 30 buildings on campus for one day. The 2 million gallons of water are continually recycled as the water recirculates through the “closed-loop system.” Not all of the buildings on campus will be served by the tank because some of them don’t have air conditioning or are connected to the central cooling plant.
The central cooling plant, installed in 2003, replaced 25 old chillers from individual buildings with four of the most efficient electric chillers available. All the chillers were relocated to a central building where they are under 24-hour efficiency surveillance.
USU and the University of Utah are the only campuses in the state using this TES tank technology so far.
“Part of the reason is because USU has a centrally chilled water system,” Mortensen said. “Our infrastructure system is unique; we have one of the best infrastructure systems in the state.”
Mortensen said this kind of energy tank system is being “embraced across the country,” but not all colleges and universities have a tank that is completely underground.
The installation for the tank comes in part after USU President Stan Albrecht signed the American College & University Presidents Climate Commitment, a document that holds the university responsible for developing a plan to work toward climate neutrality.