Geothermal: unsung hero of heating

Heat-exchange expert Doug Lockhart has two problems with geothermal heating systems: neighbours can’t see them and no moving parts attract the casual onlooker.

“If I go to your house and put in a geo-thermal system, nobody knows,” said Lockhart, owner and president of Lockhart Industries in Duncan.

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“But when you put photo-voltaic [solar energy] cells on your roof or a windmill in your backyard, there is this instant recognition,” he said. “It’s a validation you have done something positive for the environment.”

This lack of public recognition has even had Lockhart and colleagues considering whether to give out medallions or special, twirling weather-vanes to advertise a home or building whose owner has opted for a geothermal energy system.

The same lack of recognition also means Canadian homes and building owners are missing out on one of the most efficient and effective sources of heat energy in the world, heat-exchange technology.

It can be an air-to-air, home heat pump easily spotted beside many a suburban house. It can be a system of heat-collecting pipes arranged in coils and buried underground.

Or, those coiled pipes can be arranged on the floor of the ocean, a lake or year-round pond, to give up the water’s heat to a nearby building or home.

Brentwood College School at Shawnigan Lake has invested heavily in an ocean system and saved hundreds of thousands of dollars in heating costs.

But still, heat-exchange technology is a tough sell.

Municipalities get squeamish about drilling rigs and trenches during installation. Home builders are reluctant about installing anything that adds costs. The public often just don’t understand it.

“The biggest problem is people just don’t know what the technology can do,” said Lockhart.

“It’s very, very nice technology,” he said. “But it’s just out of the core competency or core knowledge of most people.”

Heat-exchange systems use the physical principle that energy — heat — will flow from a warm space, such as the ocean, the ground or the air, to a relatively cooler space. In this case, the cooler spaces are coiled pipes, usually containing a pumped-through liquid that gets warmed.

So those pipes with their liquid are collecting heat, whether it’s from the ground, the air or the water.

The technology is not new, either. It has been around for over 100 years and is used in refrigerators.

The kitchen fridge collects heat from its interior and the stored food, and then exhausts that heat out the back, off coils or with a fan.

So with a heat pump or any other kind of heat-exchange system, imagine a refrigeration unit attached to a home, But when heating a home, it’s working in reverse to the fridge, collecting heat from outside or underground or water and exhausting that heat to warm the interior.

To operate, a heat-exchange system like a heat pump uses a small amount of electricity to power a pump to circulate a fluid or gas (propane is used in some places) through a compressor. When the liquid or gas is compressed, it becomes hot and is circulated through tubes, perhaps across fans to blow the heat into the home, usually through ducts like other forced-air heating systems.

That fluid, still under pressure, is then passed through a valve into a wider space in the tube where it expands and releases the last of its energy and cools.

Think about the propane in a tank. Open the valve and the escaping gas, suddenly expanding in the open air, will feel ice cold even when the metal tank feels warm to the touch. The same effect can be experienced with an aerosol can of hair spray.

But if that cold, expanded liquid in the heat-exchange system is passed through a tube that is in contract with the relatively warmer outside air, ground or water, the laws of physics kicks in. The heat will flow from the warmer place to the cooler place, in this case the liquid inside the tube.

That transferred energy, or heat, will be pumped back to the compressor, where it heats up again. But included in the energy of that hot, compressed liquid is the heat it picked up when it circulated through the pipe in contact with the air, water or ground. The total heat gets blown into the house before re-circulating.

Electricity powers only the small pumps, fans and compressors. But when that energy in terms of electricity is considered as part of the overall heat energy released to the house, the ratio is many times over, 2 1/2 to one with a standard heat pump, five to one with geo-exchange and a staggering seven to one with ocean heat.

And most modern heat pumps can be run in reverse. So in hot summers, they can cool a house by collecting the heat indoors and exhausting it outside into the air or back into the ground or ocean.

The description is over-simplified. For example, geo- and ocean-exchange systems use multiple pipes that exchange heat with one another. That way, pipes running underground or underwater can use something harmless and nontoxic, even water, and save the local environment from a threatening leak or spill.

But few Canadians recognize the potential of the technology, especially when it’s applied to the ground heat exchange.

Guy Dauncey, a founder and communications director of B.C. Sustainable Energy, said one reason is the name “geo-thermal.”

It’s actually a better descriptor for a totally different technology: the one used in places such as Iceland, a land with lots of hot springs and other related volcanic activity. Power engineers drill holes to extract steam to drive turbines and generate electricity. But it’s not the sort of technology for use on Vancouver Island or most of Canada.

“One goes two kilometres into the ground to pick up steam to run a generator in a big power station,” said Dauncey. “The other just puts pipes under your house to heat your home.”

“That’s why in the industry ‘geo-exchange’ or ‘ground-source heat’ is preferred,” he said. “But the public likes the name ‘geo-thermal,’ so it’s kind of stuck.”

Dauncey, however, is bullish on the entire family of heat-pump technology, whether it transfers heat from the ground, ocean or air.

“It is the heat source for the future,” he said. “When you take away oil and gas because of the damage fossil fuels are doing, then you are left with electricity.”

“Now, that electricity can drive a heat pump or it can be used as straight electricity, but that is just inefficient,” said Dauncey.

Another issue, however, is the upfront cost of heat-exchange systems. Heat-exchange technology for the home is more expensive to install.

Dave Young, general manager of West Bay Mechanical Ltd. with widespread expertise in plumbing and all variety of heat systems, estimates a standard oil or natural gas-fired furnace will cost about $8,500 to $10,000 to install.

A heat pump, extracting heat from the ambient air, meanwhile, costs roughly $13,000 to $15,000 to install. If you are looking at geo-thermal heat exchange, the cost increases by $20,000 to $30,000 or more because of the high cost of drilling or trenching on Vancouver Island.

Also, those coils under the ground need space to collect or radiate heat. So small city lots are often insufficient, and the rock and glacial till of Vancouver Island can make it costly to drill deep. This often makes a standard home heat pump a good alternative.

Meanwhile, however, standard baseboard electric heaters for a typical suburban bedroom can be purchased for under $100 each. A homeowner will need one for every room but still, the cost is small compared to geo-exchange or even a heat pump.

Savings with heat exchange will pay off the investment in between five and 10 years. After all, the owner of a heat pump or geo-exchange unit doesn’t pay for gas or oil to run a furnace or for electricity to power baseboard heaters. But those initial costs can be off-putting.

Casey Edge, executive director of the Victoria Home Builders’ Association, said the high cost of homes and land in B.C. make it tricky to add any costs, particularly to a new homes..

“Every cost becomes significant,” said Edge.

It may be because Canadians don’t typically imagine living in the same house for more than 10 years. They imagine moving up to something nicer or even downsizing to something smaller. Or they think they can retro-fit later if they want to improve the heating system.

Edge also said the efficiency of new insulating materials in walls and windows has made even baseboard heaters, for all their inherent inefficiency, a reasonably economical alternative to heat a home. That counts especially in a spot like Victoria with its mild winters.

But heat-exchange experts such as Lockhart point out that even homes in Victoria need heat in the winter.

Opportunities for heat capture exist in every Canadian community with an indoor ice arena. But they are passed up whenever steam just gets exhausted to the outside when it could be heating an adjacent swimming pool.

“There’s all this steam coming out,” said Lockhart. “Heat-exchange guys, we just bleed through the eyes when we see that.”

When it comes to greenhouse gases, one home heat-exchange unit will remove the equivalent of several cars from the road. And still heat exchange remains a tough sell in Canada.

“The human animal will make no change until the pain is great enough,” Lockhart said.

rwatts@timescolonist.com

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