A giant ice ball to cool your home? Utah researchers think it just might work

May 3, 2010

Kent Udell
KSL – Scientists at the University of Utah are planning to create something very unusual on campus: a giant ball of ice. It’s an experiment that could be a breakthrough in air conditioning.

The experiment will be at a small campus building, the Sill Center, behind, in the backyard — more precisely, under the backyard.

“This entire region will become one big ice ball,” explains Professor Kent Udell, with the Department of Mechanical Engineering at the University of Utah.

Udell brainstormed the idea with students.

“Yes, well, we’ve been working on this for a lot of years,” he says.

The patented invention is just about ready for prime time, next winter.

“We believe this is a breakthrough kind of technique,” Udell says.

A smaller prototype is already in place behind one grad student’s house. It’s underneath an array of pipes.

“Well, this ice ball has been operating since February, so we don’t know exactly how big it is,” graduate student Phil Jankovich says.

The concept is to snatch winter cold out of the air and store it until summer. Udell calls it “Tivo-ing the winter season.”

“We’re recording it. We’re going to save that. We’re going to take nature’s cold, put it underground, then take advantage of that come summer,” he says.

In an array of 19 vertical pipes, a refrigerant-like Freon will rise from underground to the surface. Chilled by winter air, it goes back down again.

“It comes up as a vapor; goes back down as a liquid,” Udell explains.

Underground, the chilled Freon freezes everything — water, soil, rocks — and it stays that way.

[pullquote style=”left”]”We’re going to take nature’s cold, put it underground, then take advantage of that come summer.”
– Kent Udell[/pullquote]”If you think about it, if I make an ice ball that’s the size of a basketball and put it underground, it’s going to melt in a couple of hours,” Udell says. “If it’s the size of this table, it’s going to be a week. If it’s the size of this room, it’s going to be months to a year.”

Yes, the plan is for a very big ball of ice — roughly 35 feet in diameter. Researchers will put it deep down, at least 20 feet below the surface, so there won’t be any heaving to cause damage at ground level.

In the summer, Freon chilled by the ice ball will be pumped up to provide cooling for the air conditioning system. No need for an energy-guzzling compressor; small pumps will get all their power from solar panels.

A similar but separate system could also help heat the building in winter. That could break the cycle of using precious energy for cooling in summer and heating in winter.

“Here we’re just taking advantage of Mother Nature’s energy, and as a result we can get all of the heating and air conditioning we have come to expect with no carbon use, no fossil fuel use at all,” Udell says.

Udell and his students believe installation costs would be paid back by energy savings within five years for a typical home; two years for a commercial building.

That’s if it works. The giant ice ball experiment begins on campus later this year.

Story by John Hollenhorst

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