Part II — Geothermal, The Holy Grail of Heating/Cooling
Geothermal The lowest hanging fruit on the carbon-reducing tree, as far as I can tell. I'm convinced I'm going to hit at least 60-70% (perhaps more) of my 80% carbon-reducing diet on this technology alone — certainly the lion's share. What does this entail? Well, down this narrow lane-way, we're going to get some drill-rigs to drill a bunch of 300 foot holes, put in some pipes, and start exchanging heat and cold with the ground.
Our application has been with the City for about six weeks now — the schematic of our own geo plans is below — and I'll talk more about our project in particular next week, along with an update on how our application is proceeding with the city. As preview for next weeks discussion, and to visualize a working system, check out the four separate views: a schematic of the building and laneway, a cross-section looking along the laneway, and two vertical views.
This week I'll talk about what geothermal is, from a "how the heck does it work?" perspective. Next week, I'll talk about our progress with the city, the economics and carbon-reduction numbers, and the massive potential geothermal has as a very underused energy source.
None of the other options. I looked at compare to geothermal. A geo system is so efficient that for each unit of energy put in, it gets out three to five units of energy! Magic! It gets out five times as much energy as a conventional high-efficiency furnace! Putting geo into a typical home is, from a carbon perspective, equivalent to planting an acre of trees, or taking two cars off the road! What technology can compete with that?! The holy grail of heating and cooling, I say.
I've become so convinced that this technology is the single most viable energy contributor to our real estate that I've made a strategic investment in a geothermal startup, Clean Energy Developments Inc., and now sit on their Board of Directors. So — in the interest of full disclosure — I've a vested interest in pushing geothermal! That said - I've only acquired that interest after sniffing out all the carbon-reducing options for this hotel of ours.
What were the other (not-so-hot) options that I've discarded? Burning renewables — such as wood chip stoves — may be a nice possibility out in the country, corn-cob pipe in hand and a hound at my feet - but I would need a stove for each room, and let's not forget that wood source has to be shipped. Combined heating and generation (or co-generation, as it's known) is a pretty great idea: the heat produced as a by-product of generating electricity, a result of the inherent inefficiencies of the system, is put to use in providing heat. It's only applicable to much larger buildings, though, or even small communities. I'd have my own generator, basically, and make use of the heat it gives off. Otherwise, it's down to getting a modern, efficient boiler — preferably natural gas since it contributes much less CO2 per thermal unit than other fossil fuels.
So —geothermal heating and cooling — what is it? First off, it's not 'deep geothermal' — by that I mean drilling deep down to get at the heat given off by the core of the earth, and using it to make steam, drive a turbine and generate electricity. If you want to know about that technology see here: Geothermal.ca It's a great technology in it's own right, but it's not what I'm talking about here. Geothermal heating and cooling, often called geoexchange, involves the exchange (!) of heat (or cold, depending on your thermodynamic perspective on things) with the ground beneath your feet. How deep do you have to go? Well, if you've got a yard in which to loop a pipe, only six feet or so .... seriously ...
How does it work? Well, let's do the heat cycle first. You can see a diagram: here , There's heat stored in the ground, anything under around six feet deep stays roughly constant at 14 C, year round. There are two tricks to making that heat work for you.
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