Tuesday, 18 October 2011

Can't see the sun for the forest

Removing the pine needle carpet from Priscilla's rooftop
This past weekend at Turtle Falls we experienced the trees with almost no leaves for the very first time. There's a totally different feel to the place when the trees are bare. While there, I took the opportunity to sweep said leaves and pine needles from Priscilla's roof. We were there primarily to look at how much sun shines on the proposed house location at this time of the year. The sun sits very low in the sky right now and there are so many trees on the lot. This is a blessing and a curse all at the same time. It's a blessing because of all the reasons we know trees to be important to the environment and, of course, the character of the lot that we fell in love with has much to do with all these tall, mature trees. It's a curse, obviously, because of the tremendous amount of shade these beautiful trees provide. Not a good scenario when looking to power a house with solar panels, but definitely beneficial for passive cooling of the house in the summer. Blessing, curse, blessing...you see my dilemma here. And Ras is already stressing over the fate of certain trees.

To be perfectly honest, our heads are spinning from the little bit of research we have done so far. The first steps have us delving into the fields of passive solar design and the basics behind powering a house with solar energy. At first glance, the Keep It Simple theory, to which I fully subscribe, gets lost amongst all the compulsory calculations and the long list of essential energy-producing equipment. I can only hope that further investigation into this renewable energy lifestyle will calm the "Holy smokes! This seems complicated" fears!

Passive solar design definitely has its two camps: those who think it's the be-all and end-all and that there will not be much need for any further heating or cooling if done properly, and those who think it's a crock. This little divide in the passive solar debate has me somewhat concerned.

South-facing windows...too cold, too hot, or just right? Which is it?
Orient the house in the right direction, add thermal mass, insulate, insulate, insulate and use the correct number of south-facing windows and roof overhang. Add some properly placed deciduous shade trees on the sunny side and some strategically placed wind blocks on the north side and you're good to go. Although grossly simplified, this is the proponents side of passive solar design.

The other side of it goes something like this: windows are a big hole in the wall and no amount of insulation will make up for all those holes in the wall, regardless of any windows' high-tech qualities. As well, a wall of windows on the south side in the summer will overheat the house, increasing the need for air conditioning. Simply stated, the opponents think the house will be too cold in the winter and too hot in the summer and the blame falls squarely on the glass.

We are looking to squeeze as much free energy from the sun as we possibly can. By reducing the need for active heating and cooling, we will be able to reduce the total amount of electricity we will have to produce. This, in turn, will allow us to build a smaller (read less expensive) solar energy system for our off-grid home. Minimize, then energize...what a great concept!

I am looking for real-life examples, rather than book theory, of your experiences with passive solar design. Have you encountered times of "too cold" and/or "too hot" or something more consistent? Maybe you know a good passive solar design professional, preferably in Ontario, that you can refer us to? Please click the "comments" link in the grey box below this post to leave your stories, ideas, advice, suggestions, links, or referrals. Any and all help will be greatly appreciated.

Seeking assistance...from you and the sun,


Anonymous said...

You're right. I thought I posted a comment and it disappeared? Anyhooooo, we lived in Okotoks, Alberta for several years and they built the first solar community in North America. It's called Drake Landing and you can google it or find it at http://www.dlsc.ca/ Love all your plans! Sandy & Bryce

Mimi said...

Thanks Sandy. Will check out the website you mention.

Alex said...

My parents have a three-storey Interhab kit home on the Cape Breton side of St. George's Bay. Although the house is not an explicit passive solar design, and the site is very exposed to wind, they still have minimal heating requirements. Partly this is due to good insulation, partly due to a fairly large south-facing solarium. Their propane furnace has been left off for the entire winter some years, thanks to a wood stove that they use for maybe three months of the year. In summer there is usually enough breeze that mid-day heat is not excessive.

Don't underestimate the power of good insulation!