Geothermal systems wave of the future

By SHAWNA RICHTER
The Burlington Hawk Eye

Energy workers and environmentalists say geothermal heating and cooling systems are the best available. The systems are energy efficient, environmentally friendly and well, new.

And the Burlington Public Library plans to have one.
Saturday the library brought Geo-1, Alliant Energy’s educational van, and two geothermal buffs to share information with those interested in the geothermal heating and cooling process.

With the new building project under way, the library will begin installing parts of the geothermal unit next month. Once complete, the library will have 167 vertical wells that run 267 feet deep, said Diane Hanson, Alliant Energy trade account manager.

“Those are the magical numbers,” she added, saying people can’t just go out and buy piping and install it. Instead, each home requires a different set of piping, a different piping depth, and possibly a different layout for the system.

Geothermal energy units can be installed with straight pipes in a vertical or horizontal layout, with horizontal spiral tubing or with spiral tubing attached to straight pipes and set in a pond.

Contractors can measure homes or businesses and calculate the size of heating unit needed, also determining which layout is appropriate.

The new library will use the vertical system, which will be installed below its parking lot, near the retaining wall now being built, Hanson said.

In 2001, Great River Medical Center installed a horizontal, spiral piping system in its lake. The system is said to save the hospital $400,000 in energy bills and maintenance each year, according to Alliant’s Web site.

At this time, no one is sure how much money the library will save on energy bills.

“They say (the system) will pay for itself in five to seven years,” said Kay Weiss, library director. “(The librarians) don’t know how to operate (a geothermal heating and cooling unit), but we hope it will be easy and will mean money savings for us.”

Weiss said at the last construction meeting, crews estimated drilling the 167 wells would take 90 days or more. After the wells are drilled, the pipes will need to be installed, tested for pressure and leaks and then covered with dirt. The pipes are filled with water and environmentally friendly anti-freeze.

Hanson said the risk of pipes breaking is minimal, and if they do, contractors can find the leak and repair the damaged section. Most pipes are made of poly-ethylene plastic and are under warranty for 50 years.

Once covered, the water mixture inside the pipes will pull heat energy from the earth. Below the frost line, four feet below the surface, the earth is a constant 50 degrees in Iowa. The water will continuously draw energy from the earth and will flow through the pipes, drawing energy or BTUs to the main source of the system, the heat pump.

The heat pump has a refrigerant or compressor inside; when the energy is compressed, it creates heat, which will be blown into the library. During the summer, the system will work in the opposite fashion, pulling the warm air from inside the building and “pushing” it back into the earth.

In either case, once the building has used the energy it needs, some unused energy can be used to preheat water, serving as the water heater.

Though the system costs twice as much as standard units, it saves twice as much on bills. It also supplies a unified or constant source of comfort, Hanson said. With gas and electric costs rising, she added that many people are looking into geothermal heating and cooling.

Listening to a movie on geothermal heating systems, she said it sums up why geothermal units are the best source of energy.

“(The system provides) 70 percent of energy in the home absolutely free,” the video states. “Basically it’s just stored solar energy … it’s savings from the ground up.”

From MSNBC