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Energy alternatives gaining popularity |
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Written by Administrator
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Sunday, 05 March 2006 |
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Falling temperatures and rising energy prices may be on a collision course, creating a winter of discontent.
That's why increasing numbers of Canadians are looking for alternatives to fossil fuel systems for heating and cooling their homes. More and more are turning to geothermal heating, also known as geoexchange or earth energy, as a cost-efficient and environmentally friendly option.
The Canadian Geoexchange Coalition, or CGC, which represents the geoexchange industry in Canada, suggests that the market will continue to grow. It cites a 2002 Canadian Electricity Association market study that identified a $619 million annual potential market for geoexchange in Ontario alone, and suggests that the technology can save consumers between 35 and 70 per cent on their current heating bills.
In addition, CGC says a geothermal system often pays for itself in less time than a traditional HVAC (heating ventilation air conditioning) system.
And if all that is not enough reason to switch, geothermal energy delivers a more comfortable heat than burning fossil fuels, says Dennis Campbell, president of Polar Bear Water Source Pumps in Toronto, a company that manufactures and sells geothermal heating systems.
"The air remains at a more constant temperature, and you don't get the bursts of heat and cold spots that come with an oil or gas furnace," he says.
Campbell estimates that demand for his systems has doubled in the past year.
"But to tell you the truth, I don't keep track of the numbers. I'm too busy. I just know we're so swamped we can't keep up," he says.
His interest in heating systems began in the 1980s while selling high-density polyethylene pipe (HDPE) to industrial clients.
In the early 1990s, a potential customer suggested the product would work well in geothermal applications. That was enough to pique Campbell's interest. By 1994, he had hooked up with Roy Carrier, a refrigeration mechanic in the Orillia area, and the two of them built their first geothermal unit.
The science behind geothermal energy is simple: Heat located under the surface of the Earth, or in a body of water, is transferred through a series of pipes to a heat pump.
From there, simple refrigeration principles are used to transform the gathered energy into useable heat that is circulated through the building.
In hot weather, the process is reversed; warm air inside the building is absorbed and discharged into the underground pipe system.
"Think of it like a refrigerator that's on steroids," suggests Campbell when describing how a geothermal heat system works, "in that it absorbs heat from the Earth and circulates it through your house." (For a quick lesson on how a fridge works: http://www.home.howstuff works.com/refrigerator2.htm.)
There are two types of geothermal heat systems: closed and open loop. In a closed loop system, pipes are run to an appropriate level underground, either horizontally or vertically, and connected to the heat pump.
The loop must be buried deep enough to access the heat, which varies from region to region across Canada, and the amount of piping used has to be correlated to the size of the house. According to Campbell, temperatures at about 1.5 metres below ground in the southeastern tip of Ontario run from about 6.5C in Huntsville to 10.5C in St. Catharines. But even in the far north, the ground retains a constant temperature of approximately 5C to 8C, which makes geoexchange a practical option.
The pipes contain water, or a mixture of water and an environmentally friendly anti-freeze, such as ethanol. Methanol and denatured ethanol are the most common fluids used, but methanol is not approved for use in Ontario. That mixture absorbs heat from the ground and conducts it into the building, where a compressor is used to transfer the heat into warm air, which is distributed throughout the building.
An open loop system connects with a well, lake or pond, from which water with a constant temperature is used to warm the air that circulates through the house. The groundwater is returned to the environment.
Campbell estimates that a horizontal system for a 2,500 square foot home would cost about $25,000 to install. That would include the heat pump, ductwork, heat recovery ventilator, hot water tanks, humidifier and electrical work.
On the average city lot, where space is more limited, vertical holes would have to be drilled about 45 metres deep (or more in some cases), at roughly three-metre intervals. For a 2,500 square foot lot, a vertical loop retrofit system would run about $40,000.
"The cost of drilling makes it too expensive to install for most city houses," admits Campbell. "Currently, it is 2 1/2 times cheaper to operate than natural gas but until it is five and six times cheaper you won't find too many city installations." Campbell suggests that vertical drilling only begins to make sense for larger houses in the city, those approaching 3,000 square feet or more.
While interest in retrofits will continue to grow, Campbell speculates that the biggest gains in geothermal applications over the next five years will be rural, with growth accelerating as fossil fuels and electricity become ever more expensive.
Canadians can offset the cost of investments in a variety of energy-saving renovations, including a geothermal system, reminds Barbara Mullally Pauly, senior chief of housing programs for the Office of Energy Efficiency at Natural Resources Canada.
Under the EnerGuide program, homeowners can have an independent energy adviser measure the energy efficiency of their house and make suggestions about how to improve it. Homeowners who make improvements that produce measurable results, upon a second visit by the adviser are eligible for a rebate. The cost of this service varies from region to region.
"Rebates will depend on the age and condition of the house, and what improvements are made," says Mullally Pauly. |
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