renewable energy

Geothermal Heating

The proper term is "ground source heat pump" (GSHP). I often get questions about this technology, and I think that there are some misconceptions out there, so here goes.

How It Works

The way I think of it, there is a magical black box that can take heat at low temperatures and "pump" it up to higher ones. In Edmonton, the ground a few feet below the surface remains at about six degrees Celsius all year round. This is seasonally-stored solar energy - it accumulates in summer and doesn't cool very much during the winter because there's just so much dirt.

So, a contractor comes and drills long holes (150 - 200 feet, I think) in the back of your yard, and runs tubing down the holes. Then, when heat is needed, the heat pump runs a fluid through the tubes in the earth, and pulls solar heat from it. The exact same effect happens in reverse.

With a GSHP, you can pull 3 - 3.5 units of heat from the earth for every unit of electricity that the heat pump uses.

The Hype - Imported From Elsewhere

Using a GSHP is a brilliant idea in Manitoba or Quebec or Vancouver Island - somewhere where no natural gas is available. The thing is, if your only choice is heating with electricity, a GSHP is in effect 350% more efficient than regular electric heating. That is, with regular electric heating (like from a resistance heating baseboard heater), you get one unit of heat for every one unit of electricity invested. As stated above, the GSHP will give you up to 3.5 units of heat for every one. That's pretty good.

The brilliance of the GSHP in other locations, though, doesn't necessarily translate to Alberta. Here, natural gas is available ubiquitously. AND our electricity is mostly derived from burning coal - the enemy of the human race.

So in Alberta, the only fair comparison for a GSHP is a super-efficient natural gas furnace.

Electricity vs. Natural Gas

Most of Edmonton's electricity is generated by burning coal near Wabamun lake. The generators burn the coal, and convert about 30% of the energy in the coal into electricity. Then, it gets sent down the power line to our great city (some of it gets lost along the way, but we'll ignore that for now). If we use the electricity in a GSHP that is 350% efficient, we get 3.5 units of heat back for every 1 put in. The thing is, we're using electricity that contains only 30% of the coal's original energy value. 30% * 3.5 = 105%. A coal-fired GSHP is 105% efficient, then, when considering the energy that was initially in the fossil fuel.  read more... »

Solar Retrofit to a Mid-1960's Edmonton Bungalow

I've started a home renovation that will include the installation of solar thermal collectors to help provide domestic hot water and help heat my house. I thought there would be other people like myself who would be interested in my experience - both good and bad. Here goes . . .

Like many people, I'm interested in increasing the efficiency of my home and reducing my gas and power expenses and would love to live in something like the Riverdale Net Zero house. Also like many people, I don't have the means to built my own net zero house. Add to this is the fact that I really like the house I'm in now and love the location and we've got a recipe for a renovation.  read more... »

Solar Salad

We get a lot of sun in Edmonton. In fact, I've heard that we have as many sunny hours as Miami. Moving into the uncertain future, that's an asset.

On May 6, I decided to leverage that asset into a sun-cooked potato salad.

Solar Ovens

The concept of a solar oven is very simple: a black, insulated box with glazing (plastic or glass) is aimed towards the sun. It's amazing how the simplest concepts can be so powerful. It's a cinch to get my solar oven up to 200 degrees Fahrenheit, and during the hottest months it will hit 300 degrees.  read more... »

Insolate and Add Mass

Insolate

in·so·late [in-soh-leyt] verb: to expose to the sun's rays

When planning a cold-climate eco-home, you first insulate and seal, then you insolate. That is, you design the house to capture as much energy from the sun's rays as possible.

The Mill Creek NetZero Home (MCNZH) will be situated on a lot that is 33' wide from East to West. Local bylaws dictate that the sideyards of a house must be a least 4' wide. That leaves 25' of width for our all-important south wall. As you can see from the above picture, we have maximized the opportunity.  read more... »