This is part of an article printed in the Cincinnati Enquirer on Aug 4th 2010.
UC will cool off with 4M-gallon tank
CORRYVILLE - The University of Cincinnati football team will be practicing on more than synthetic turf at UC's new Jefferson Avenue Sports Complex.
About three feet below the surface will be 4 million gallons of water, which UC will cool to 42 degrees and pump out to buildings all over campus early each morning, providing critical cooling capacity and saving at least $500,000 a year in utility costs.
The $5 million project will be the biggest thermal water storage tank in Ohio and the second at UC, making it the newest commitment to increasing sustainability efforts on the region's biggest college campus.
By comparison, the Sunlite Pool at Coney Island holds 3 million gallons of water and the Newport Aquarium holds 1 million gallons.
Joe Harrell, executive director of utilities at UC, said attaching the tank to a new construction project is a once-in-a-generation opportunity to increase UC's cooling capacity.
"That tank is going nowhere," he said. "That hole in the ground will be a hole in the ground 50 years from now."
The thermal tank will be operating by March under the half-field that will open by early 2011. The full field, which will include a bubble for cold-weather practices, is scheduled to open this fall.
When it starts operating next spring, the thermal storage system will work like this:
Early each morning, the tank will pump 42-degree water to buildings around campus, where air is blown over it to cool the space. At the end of the day, the 54-degree water is pumped back to central chilling stations to be cooled again.
UC has operated a 2.8 million-gallon tank under the Care/Crawley building on the medical school campus for more than a decade.
By installing large storage tanks, UC can cool more water using less-expensive overnight rates and avoid using all of its chillers located at two central power plants. The new tank will add about 5,000 tons of chiller capacity, Harrell said.
The storage tank is the latest program at college campuses across Greater Cincinnati and Northern Kentucky to cut electricity and water usage, along with other environmentally friendly efforts.
******Please go to the papers website for the full article******
So the question is, does this project meet the goal of cutting electricity? Is $500,000 a good payback on a $5 million investment?
This is an example of a technology that saves energy budgets without necessarily saving energy. We have run a similar thermal storage system for about the past seven years. Our system uses a little more energy than if we were not using the storage system. The savings depend on reducing demand charges and taking advantage of lower night time electrical rates. Where those advantages do not exist, the system will typically not save energy dollars.
I will say that having 3 million gallons of very cold water in the storage tank each morning does give a sense of security. We have dealt with chiller outages, condenser pump failures and other similar problems without the campus even knowing about it.
Always thought that I had gone to a "Cool School" for undergrad. Now I am convinced. Sure could have used some of that 42F stored water in July-August back in the 60's, though!
As an energy saving idea would be fine, after you optimized all occupancy scheduling, developed the very best PM program available, and trained all your mechanics to run equipment at the highest optimization. You might also want to put a program in place that would indicate a deviation from optimal performance in a reasonably short time; I like 72 hours.
So from a purely energy standpoint you can do a lot with your money before the big hole gets dug.
On the operations side I like the idea, although I might go for three or four tanks instead of one 5,000,000 gallon one.
A Google search shows a number of hospitals on the campus. The reserve cooling capacity can truly be a life saver for a patient. When the domino effect of a co-generation plant interruption is considered curtailment of non essential usage and a large reserve of chilled water is needed in a medical setting.
A second benefit of large chilled water storage in older sprawling campuses is the settling tank capability for entrained dirt, rust, and biological debris. I have seen a side stream filter installed on these tanks that allows "polishing" of the stored water. Clean water helps maintain high efficiencies it the temperature differential.
I did get a smile about the 42 degree water leaving in the morning and coming back in the evening at 54 degrees. I wonder where it spends the day.
Bernie