2/16/2012
By MICHAEL STRAND Salina Journal
The March 2011 earthquake and tsunami in Japan weren't felt directly in Salina, but it's part of the reason 52 football-field-deep holes are being drilled into the rock under the former Marymount College campus.

The college's former administration building is being converted into condominiums, called Marymount Properties, complete with an underground parking garage.

The original administration building was heated with steam, explained architect Donnie Marrs, with Marymount Properties. However, the nearby Kansas Highway Patrol building houses the boilers that generated the steam, so Marrs had for several years been installing individual heating and cooling systems for the offices housed in the administration building.

That requires an outdoor air-conditioning unit for each office, which detracted from the aesthetics of the development, Marrs said.

"We now have 17 of them, and we'd have needed 40 more," he said.

In looking at alternatives, Marrs initially settled on a roof-mounted system, which is being used for the first four condos in the development's first phase.

However, the systems are made in Japan, and the price increased significantly after the earthquake there, pushing him to take another look at a geothermal system.

Hot, cold from the ground

"Because of the price increase, it was more desirable now than several years ago," he said.

The system involves drilling 52 300-foot deep, 8-inch diameter shafts, putting a loop of 1.5-inch pipe into the hole, and filling the hole with a grout mixture of concrete and bentonite; all 52 wells are then hooked together, and water/glycol is circulated through the tubing, through a heat pump in each residence, and then back into the ground.

In the summer, the water picks up heat from the individual units and transfers it to the ground; in winter, the water picks up heat from the ground and transfers it to the building.

Marrs noted that because Salina typically has more days when people use air conditioning than heating, heat will build up in the well field over time.

"We'll be logging supply and return temperature to see how our well field is performing," Marrs said.

The Salina School District's new maintenance building also will use a geothermal system for heating and cooling, but based on a different concept. That system will pump groundwater to the surface, conduct the heat exchange, and pump it back into the aquifer, while the Marymount system uses its own fluid.

A 3-year payback

The Marymount system will cost more up-front, Marrs said. However, because the energy cost is less, he expects the extra cost to be paid back in about three years.

The system will also provide hot water for each unit, Marrs said.

This is by far the largest geothermal system Pestinger Heating and Air-Conditioning has installed, owner Tom Pestinger said.

"We just got done with a 25-well system in Lindsborg, for the Birger Sandzén Gallery," Pestinger said. "It's 25 wells, each 200 feet deep."

The number and depth of wells determine the heating and cooling capacity of a well field, and wells also can't be so deep that they penetrate layers of salt water.

Altogether, Pestinger said, the Marymount system will provide 100 tons of heating and cooling capacity, enough for the building's south wing; a second well field, also supplying 100 tons of heating and cooling, is planned for the second phase of the project.

The drilling is being done by Associated Drilling of Wamego and will take about three weeks, Pestinger said.

"My brother drills wells, but this is way out of his league," Pestinger said. "The rig itself costs over $1 million."

Garage nears completion

The first phase of the Marymount project comprises 25 condo units, ranging from 1,000 square feet to several thousand square feet. So far, Marrs said, six have been sold and closed on and two others are under contract.

The underground parking garage also nearing is completion, Marrs said. He estimates work on the structure will take another 30 days, and after some additional masonry work, it will be ready to be covered.

-- Reporter Mike Strand can be reached at 822-1418 or by email at mstrand@salina.com.

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