New Mount Mercy building will use geothermal system

As part of its ongoing effort to reduce its overall carbon footprint, Mount Mercy University will use a geothermal system to heat and cool its new $8 million University Center.

Sam's Well Drilling of Randolph, Wis., is drilling 53 wells 300 feet deep that will replace standard heating and cooling equipment found in other campus buildings. Pipes filled with fluid will be installed in the wells, from which either cooling or heating will be extracted by 36 heat pumps.

"We dug a test well last spring to determine the ground temperature and how deep the wells will have to go to get the kind of heating and cooling we need," said Barb Pooley, Mount Mercy vice president for finance and business operations. "The geothermal system will cost about $225,000 more than a standard system. We will get a nice rebate from Alliant Energy when the construction is done and we also will realize considerable energy savings.

"We figured that the payback was about six and half years. That made going with the geothermal system a no-brainer."

Dwight Schuum, managing principal with Design Engineers in Cedar Rapids, said the geothermal system will take advantage of the earth's constant temperature.

"Around here, once you get below maybe 15 feet, the earth's temperature stays at about 55 degrees year-round," Schuum said. "Geothermal systems are better than conventional cooling systems and a lot better than conventional heating systems. The energy savings is between 40 percent and 50 percent because we do other things to improve efficiency, such as using the exhaust air to preheat fresh air coming into a building."

Pooley said the 43,000-square-foot University Center also will incorporate dual lighting in all the offices. Lighting will start at a low level and increase on demand, shutting off automatically when an office is not occupied.

"We're trying very much to become more environmentally sustainable,." she said. "The bathrooms in the new University Center will have dual-flush toilets, which should dramatically reduce water use."

Dual-flush toilets enable the user to flush with a small amount of water for liquid waste and a larger quantity of water for solid waste. Invented in Australia, dual-flush toilets been proven to save up to 67 percent of water use in most businesses, homes and schools.

Pooley said Alliant Energy played a major role in the design of the University Center through its Commercial New Construction program.

"Alliant Energy brought in a design firm to look at what we planned to build," she said. "They created a spreadsheet that showed all the different kinds of lighting, controls and heating, ventilating and air-conditioning systems. We looked at where we could get the most savings and the best payback.

"They put all the systems into six bundles for us to consider. Three of the bundles had energy-saving lighting and conventional HVAC systems and three had different lighting systems and geothermal.

"Alliant Energy paid for all of the design work as well as the development of the bundles."

Schuum of Design Engineers said the geothermal well system will be ready to heat and cool the University Center when it is scheduled for completion in the winter of 2011-2012.