A 15-Acre Liquid Asset

Staff | September 28, 2010

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Mechanical Inc. has a solid track record of successful hospital and green building projects, and that combination made them the mechanical contractor of choice for Sherman Hospital's $310-million replacement hospital in Elgin, IL. Scheduled to open in late 2009, the hospital will be mainly heated and cooled by geothermal energy from a 15-acre artificial lake next to the facility.

"The geothermal lake was a wise choice, both economically and ecologically," says Brian Helm, president of Mechanical Inc. in Freeport, IL.

Helm adds that Mechanical Inc. is installing the hospital's intricate heating and cooling system, including 275,000 feet of 2-inch piping in the geothermal heat exchanger — a component which uses the lake's natural geothermal properties to heat and cool the hospital. Mechanical Inc. is also installing the medical gas piping and the plumbing in the facility.

Mechanical Inc. is working with Walsh Construction Co., the construction manager for the replacement hospital. Project Executive Larry Voss is overseeing the project for Mechanical Inc.

"When we originally did the return on investment for this initiative, it came back showing a savings of at least $1 million per year," says Dawn Stoner, project specialist for Sherman Hospital. "Over the last two years, since design, prices have only escalated. We see this as a great savings for the hospital, but it also allows us to use a renewable energy source. This is a great decision for any facility, big or small. We are all responsible for making our environment better."

How The Geothermal Lake Saves Energy

"Sherman Hospital will be the first hospital in Illinois to build a geothermal lake," says Selena Worster of Mechanical Inc., project manager for the geothermal lake. "This lake will also be the largest of its kind in the nation."

According to Worster, solar energy is absorbed by the surface layer of the 17-foot-deep geothermal lake, resulting in a natural thermocline and a relatively consistent temperature at the bottom of the lake.

The lake will have a natural clay liner and be filled with rainwater. Water and methanol-bearing coils of piping, or heat exchanger rafts, are stationed at the lake's floor. The steady temperature at the bottom of the lake will be the heating and cooling source for the solution passing through the coils. This solution, in turn, is circulated by a lake loop heat-pump system.

When the circulating solution reaches the water source heat pumps, the energy is converted to warm or cool air to regulate the temperature of the majority of the hospital's rooms. The emergency room and surgical suites will employ a traditional heating and cooling system, since they require cooler temperatures.