If you could take a look under the cornfield next to Dobben's farmhouse, you'd find a closed loop system made up of hundreds of feet of high-density polyethylene pipes buried below the frost line and filled with diluted antifreeze. His system features pipes laid in a horizontal configuration, though a costlier vertical design can also be used depending on the amount of space available and the surrounding terrain.
The antifreeze mixture travels through the pipes absorbing heat before entering his home through the basement. Here, the pipes connect to a geothermal unit that's about the same size as a traditional furnace. A heat exchanger extracts the heat from the fluid and a compressor upgrades the heat to the desired temperature. This warmed air is then circulated through the home through the same ductwork used for his old forced-air furnace system.
Instead of drawing heat from the ground, an open loop system draws water from the bottom of a deep well, lake or aquifer. An open system is more efficient than a closed system and is cheaper to install but is more susceptible to complications such as minerals in the water, which can degrade the system, or a depletion of the water source.
The beauty of geothermal systems is that in the summer, a flick of a switch reverses the fluid flow and the warm air from the house is discharged back into the ground. Homeowners get the benefit of heating and cooling in one unit, eliminating the need for a separate furnace and air conditioner. There's also no need to turn down the system during peak demand periods.
Good for the homeowner
With proper maintenance, such as monthly filter changes and annual antifreeze top-ups, a system should last more than 25 years, though the compressor might last only 10 years.
In addition to the heating and cooling functions, there are units that supplement hot water heating. These essentially bring the home's water temperature up to 75 degrees "for free."
The other bonus is the quality of the heat. Geothermal units maintain a very even temperature throughout the house so there isn't the blast of hot air or draughts common to combustion furnaces.
Good for the environment
In fact, according to the David Suzuki Foundation, "geothermal heat pumps are the most energy-efficient, cost-effective and environmentally friendly home heating and cooling systems available."
This is good news for a country that produces about 700 megatonnes of greenhouses gases each year (equal to two percent of total global emissions from a country with half of one percent of the population.) Forty-five megatonnes of emissions come from residential buildings alone.
Geothermal heating systems can help reduce greenhouse gas emissions by more than two-thirds, depending on the alternative source of power available (there's a greater reduction of emissions for homes that rely on coal-fired generators or oil-burning furnaces that those that use electricity.) Homes can even be 100 percent emission-free if the energy used to power the compressor unit is sourced from solar panels or a green power distributor.
Even though the heat exchange and compressor require electricity to run, the costs to extract the heat are still cheaper than with traditional heating systems.
"It's the cheapest operating cost of any heating or cooling system for a residential or commercial application," says Travis Schmidt, business development coordinator for NextEnergy Inc., a distributor of geothermal systems in Elmira, Ont. Compared to oil, propane and electricity, utility bills are almost one-quarter the cost and compared to natural gas, they're one-half the cost.
"Our entire utility bill for our house -- heat, hydro, electricity and hot water -- is equivalent to what we paid for just heat in our old house," says Joanne Fritz, owner of a two-year-old, 2,900-square-foot home in Wellesley, Ont. equipped with a horizontal loop.
Still, besides the major excavation that needs to be done to install the loop (though the entire system can usually be installed in three days,) the biggest obstacle to a more widespread adoption of geothermal technology is the large upfront capital cost. A typical 2,000-square-foot home in central Canada might require $20,000 for a horizontal loop and even more for a vertical loop.
"It's definitely more expensive to install," says Bosman. "However, if you're a customer starting from scratch or if you require a furnace that needs replacing, a new chimney liner or a new oil tank, you have a substantial investment that you're looking at already." He says the additional cost is typically a five to six year "payback," which refers to the number of years before the savings in annual operating costs exceed your initial cost to install.
So whether you're looking to reduce your fuel costs or do your part to help the environment, you might want to take a second look at the ground beneath your feet.
"Geothermal can be put in almost every home in Canada," says Schmidt. "There are cost factors that need to be considered and a few limitations as to where loops can be put in, but aside from significant infrastructure beneath a property, there are very few places geothermal can't go."
Fiona Wagner is a freelance writer in Georgetown, Ont.
|-- Posted: Jan. 5, 2007