Agricultural engineers at Iowa State University are looking into using drainage water as a cost-effective way to help keep buildings cool during the hottest weeks of summer.

“I think it has a lot of potential,” Iowa State University Extension ag engineer Kris Kohl says.

The system would involve the collection and circulation of drainage water through a network of pipes installed within livestock buildings. The collected water from the field drainage tile would be pumped through the livestock building, then flow through the soil to cool before being recirculated.

The practice is still in the early trial stages, and Kohl says Iowa researchers plan to construct a system to work on a smaller scale, then try it with a full-size livestock building.

“At this point it’s conceptual,” he says.

But Kohl says the system would take advantage of existing resources. It would take inspiration from a traditional air conditioning unit, except instead of using freon it would use water drawn from underground.

“This would use water and basically we would have drainage tubes that would be 60 to 80 feet apart,” Kohl says. “…We’re planning on using water as a recirculating system just like you would freon.”

The water would run into the lines to cool the building, then back into the drainage line underground.

“The soil temperature where I’m at in Iowa rarely exceeds 60 degrees,” Kohl says. “The average temperature where I am is 42 degrees. At 4 feet depth, water rarely would exceed 60 degrees.”

He says the water circulation system could be used in combination with ventilation during the hottest weeks of the summer to help keep temperatures down in livestock buildings.

“It only takes about a half-inch to bring the water table up a foot,” he says. “It would only take a small amount from a well to raise the water level.”

Kohl says the water-cooling system could be a much cheaper alternative to the cost of constructing an air-conditioned building. While there is still research to be done, he says it could be a useful system to deal with temperature extremes in a relatively low-cost, sustainable way.

“I think it certainly has that potential,” Kohl says. “In Iowa and Missouri, we’re in the very centre of the continent. We end up with very hot summers and very cold winters. What we’re trying to do is use some of that cold that is stored in the ground to deal with the hottest two weeks.”