Geothermal heating, cooling gaining popularity

February 14, 2011 - When Steve Lee from Carnegie Mellon University looks at the idea of pulling home heat out of the ground, he sees inarguable sense.

"I would absolutely recommend it," says the head of CMU's School of Architecture. "It makes use of the great efficiency of a known technology. In an annual basis, you take from the Earth and you give back."

He is talking about geothermal heating and cooling of homes or buildings, a technique that uses water warmed in sunken tubes to create the source for heat. That heat, intensified by a condenser in a furnace-like unit, can provide forced-air heat, radiant floor heating and even heat hot water.

It can be at least twice as efficient as the best heat pump, Lee says.

It is a method "that looks like it is going to take off," says Dan Cribbs, one of the four partners in Advanced Geo-Solutions of Greensburg, a three-year-old company that specializes in that work.
Mike Motta, from Motta Heating & Air Conditioning in Beaver County, has been doing geothermal work for 15 years and says 2010 was the firm's biggest year ever.

A report delivered in October to the International Ground Source Heat Pump Association, headquartered at Oklahoma State University, says there were 11,000 sales of geothermal units in North America in 1983. In 2009, there were 92,000.

Dan Dudas from Eighty-Four, Washington County, saw that method as a logical way to replace the heating system when his heat pump died in the heavy snow last February.
"It's a bit pricey, but it will pay off in the long run," he says of the system that cost $19,000 for gear and installation.

The difference in price for a new home makes installation of a geothermal system a "no-brainer," Lee says. Air conditioning, water heating, heating and ductwork might come to more than $11,000. A geothermal system could go to $25,000, installers say, but a tax credit and overall efficiency would make it pay.

The difference in price for retrofit work is greater -- maybe $19,000 versus $7,000 -- but the tax credit and efficiency still make a difference.

Tom Gogal of Ross decided the efficiency was impossible to pass up in the home he recently built. Between the efficiency and a 30 percent, no-ceiling tax credit, the cost seems less daunting to him.

"If you save $1,000 a year, in five years it will pay itself off," he says.

A FAIRLY SIMPLE OPERATION

In most cases, geothermal units involve U-shaped tubes of piping called ground loops being inserted about 160 feet into the ground. Each U, then, is 320 feet of tubing and filled with water loaded with an anti-freeze-like substance, say Motta, Cribbs and others involved in the work. The temperature of the ground always is about 55 degrees so there is some constant warmth and the anti-freeze-like material is for when the water gets higher, near the house.

The number of ground loops is determined by the size of the house, with a 2,000-square-foot home, for instance, using four loops.

Water flowing through the loops is taken to a compressor unit that creates heat for the home in the winter. It does that in a heat-on-heat process that creates higher temperatures than supplied by the ground. In the summer, hot air is drawn from the home in a reverse process, creating cooling without air conditioning.

The most efficient units also can be used to heat water, eliminating another need for natural gas or electricity.

Darwin Burtner from Western Pennsylvania Geothermal in Saxonburg, Butler County, explains geothermal heating is the most efficient current system because it creates heat from the warmth of the ground rather than through combustion.

Electric bills probably will increase because of greater use of pumps and blowers, but natural gas is eliminated.

Natural gas furnaces with 95 percent efficiency, he, Motta and Cribbs point out, still lose 5 percent in the combustion process. But, they say, for every dollar spent in the geothermal heat process, about $4 of usable energy is created.

The three installers agree a typical home loop installation can be installed in a 20-foot square, and Gogal says his three loops fit in even less square footage.

Burtner says that makes it doable at virtually any property, but warns that one of the real issues is having enough space to get a drilling rig to the site.

That could eliminate its use on many city properties.

GROWING INTEREST

While geothermal heating and cooling seems like a fairly new process, it dates back to the '70s. Motta has been working with those units for 15 years. John Cari, the eastern Ohio-Western Pennsylvania manager for WaterFurnace, an Indiana-based geothermal company, says he installed a system in his Ohio home in 1980. He sold the house in 2003 and had not replaced the compressor-heat pump unit, although he says for the most part that needs to happen about every 20 years, similar to a furnace.

He says Hurricane Katrina began to increase interest in geothermal heat as oil drilling was threatened and use of fossil fuels looked riskier.

But by 2007 and '08, he says, interest began to decline because of the poor economy.
"It just seemed too costly to most people," he says

But interest is stirring again, mostly because of the Internet, say Motta and Cribbs. Homeowners read about it and begin investigating it, which leads them to installers.

Interest goes other directions as well.

Doug Skowron is a consultant to Pittsburgh Gateways, the nonprofit group that is masterminding the conversion of the Clifford B. Connelley Trade School in the Hill District into the Energy Innovation Center. He says geothermal heating is a big part of the engineering plan for the site that will act as a conduit for environmentally oriented learning and jobs.

Bill Cagney is business manger of the International Union of Operating Engineers Local 95, which will be one of the tenants of the building.

He says using geothermal heating/cooling in the $35 million project is purely logical.
"The whole concept is built around the use of renewable energy," he says. "It will prove technology can pay the bill."