An Illinois hospital builds the largest geothermal lake in the country.

Photos: Mechanical Inc.

Talk about healthcare reform!

When Sherman Health, a not-for-profit community-governed healthcare system, planned to build its $310 million replacement hospital in Elgin, Ill., it sought to create a future-focused design that brought together ideas of nature and technology.

One of the highlights of this new green hospital is a 16-acre geothermal lake located next to the building, which will not only help create a healing environment for patients, it will also make Sherman one of the most energy-efficient healthcare facilities in the country.

“Sherman Hospital will be the first hospital in Illinois to build a geothermal lake,” notes Selena Worster, project manager for the geothermal lake and associate of Mechanical Inc., the mechanical contractor for the project. “This lake will also be the largest of its kind in the nation.”

Mechanical Inc. in Freeport, Ill., boasts a solid track record of successful hospital and green building projects, but building an artificial lake - and undertaking a geothermal system of any type - was a first for the company.

Worster admits there was a steep learning curve for her team. “Quite a bit of time and effort went in to planning the installation and I think it shows in the great work performed by the crew and the professional installation,” she says.

At Sherman, Mechanical Inc. sunk 275,000 feet - nearly 185 miles - of 2-inch HDPE piping to connect to 171 massive geothermal grids. Water- and methanol-bearing coils of this piping were placed on heat exchanger “rafts” stationed on the lake’s floor 18 feet down. There are approximately 822 heat pumps, which together create the geothermal system that will heat and cool the facility.

“The wind was a challenge on the lake. The boat pulling the heat exchanger rafts and supply-and-return piping kept getting blown off course,” Worster recalls. “It took the first three or four days to make our technique efficient.”

The heat exchangers are key to the system, since they help convert the lake’s natural geothermal properties into efficient and pollution-free energy.

Worster explained the process in which solar energy is absorbed by the surface layer of the geothermal lake, resulting in a natural thermocline (where warmer surface water is separated from the colder deep water and the temperature decreases rapidly with depth) and a relatively consistent 55-degree F temperature at the bottom of the lake.

Projections show this system will help Sherman significantly reduce operating costs (gas and electric) by nearly $1 million annually. And even though this system cost 13 percent more to install than traditional energy sources, the investment will more than pay for itself in just a few short years, Sherman administrators state.

“This lake is beautiful, environmentally sound, and it was the single-most responsible financial decision we could have made for our hospital,” says Sherman CEO Rick Floyd.

More Than Money

Besides the fiscal savings, Sherman Hospital had many other reasons for taking a chance on a geothermal system:

  • Sherman already had plans to build a six- to seven-acre water retention lake on the replacement hospital site, so building a geothermal lake was a logical and easy extension of those plans.
  • The fact that this hospital was built from the ground up played a part, since it is sometimes difficult for a building to convert to geothermal after it is constructed.
  • The 154-acre replacement hospital site is expansive and had plenty of room for the 16-acre lake.
  • The geothermal lake will allow Sherman flexibility to expand in the future, because it is easy to enlarge the geothermal system when the hospital grows.

Sherman’s due diligence period showed that one other hospital in the country had embraced geothermal technology on such a large scale with unquestionable success and served as a model for its own geothermal lake. Great River Medical Center in West Burlington, Iowa, built its geothermal lake five years ago and is recognized as one of the most environmentally friendly hospitals in the country. It saves more than a million dollars annually over the cost of heating and cooling its old campus.

According to Dawn Stoner, project manager for Sherman, when the leaders at Great River offered a resounding “YES” when asked if they would build the 15-acre geothermal lake again, Sherman decided to make the investment.

“There definitely seems to be a trend in the healthcare industry to look at incorporating green/sustainable design into new facilities,” Worster says. Many hospitals work on guiding principles to create a healing environment for patients and to also care for the environment around them. “It makes sense that people are interested, because this lake combines functionality with beauty. It captures the rainwater runoff from the building and heats and cools the building, while at the same time provides a nice area for those visiting Sherman to enjoy nature.”

There will be a recreational path around the perimeter of the lake for the community to enjoy, as well as a fish-feeding dock, so the lake creates a therapeutic vista for patients as they heal and serves as a comforting symbol for visitors and staff.

Sherman broke ground on the 255-private bed facility in June 2006 and expects construction to be completed in late 2009. The lake took more than three months to complete, but once it’s up and running, the system will be simple and inexpensive to repair and maintain. It will also be quieter than traditional HVAC systems, which will improve patient comfort.

An all-glass manifold building will house the heat exchanger pipes, allowing guests to watch the process and students to learn about the method of capturing geothermal heat.

“Green/sustainable design is here to stay in the marketplace,” Worster states. “I forsee that in the near future it will become the norm that all buildings are designed to be sustainable. And not too much further down the road, the next big push will be for buildings to be carbon-neutral.”

For more information about Sherman Hospital and its green initiatives, visit