Posted on 09/25/2014 11:16:29 AM PDT by Prophet2520
Besides the obvious advantage of a free heating source (as long as the sun continues to rise and set) we have discovered a few more advantages:
(Excerpt) Read more at livinggreenmag.com ...
Passive solar is not a bad idea, but you will get better returns from using a high R-value insulation in walls, attic space and even basement walls. I would also use a reflective roof matting under shingles at least on west facing roofs. Energy efficient windows, doors and a high efficiency HVAC system should round out your construction.
One of the main things you do is the length of your overhangs. This way in the summer and the sun is high the overhangs block the sun coming into the windows. Then in the winter when the sun is lower the sun comes more directly into the window.
Planting deciduous trees(trees with leaves) on the south side of your house helps too. They shade your house in the summer and when the leaves drop in the fall they let the sun come through.
Another method is to create heat sink. This would be an area/space/room on the south side of the house with all windows and some kind of masonry floor. It should have doors to close it off if it gets too hot or cold. The walls should also be made out some dark colored masonry product. I have also seen people put large dark colored barrels filled with water. The idea behind this is to absorb the heat from the sun during the day and then let it flow via natural convection(heat rises)to warm the surrounding rooms. Greenhouses work the same way.
None of these things will keep your house 70 degrees on a January day when it is 20 out and snowing. However, they will help when its 45 and sunny. The most important thing for heating or cooling is you have a well sealed and insulated house. If you have single pane windows, doors with cracks around them and 3” of insulation in your attic, your waisting your time.
This is an *awesome* website. No envirofreaks, just tinkerers experimenting with different concepts and configurations and often measuring and posting their temperature data.
That site is what solar is meant to be. If you can’t find some great tips there for your home I’ll be shocked.
This is not some new-fangled tech some greenie-weeines made up. House designers have used these techniques for hundreds of years. They just fell out of fashion with on demand forced-air HVAC systems becoming cheap and efficient.
That is called a Heat Sink.
I read an article about a passive solar, earth berm house in NH - owners went away in dead of winter for two weeks and when they came back it was still 50 deg inside.
Passive solar design also takes into account summer heat gain - different solar angle, shaded windows, insulated roof, light colored roof.
I always figured the best use of solar panels was to run the AC in summer heatwaves.
The Salt Box house design was meant to have the front of the house(with all the windows) face north. The long sloping roof on the back faces north.
As a side note, I learned from my mother in-law(she knows everything), that the hole in BIRD HOUSES should face EAST. The birds like them that way because they will not get too hot in the summer.
Smart. Whatever works.
The way this works is a log home within a log home is built, and a constant flow of insulated air flows around the inner home. It’s the delta between the heat of the day and the cool of the night that keeps things comfortable. At least that’s what they and their testimonials claim.
http://www.enertia.com/howitworks.html
Converting the heat to electricity is tricky. How would you do it?
I’ve never built or bought one but grew up in one, my folks were not exactly leftist but they did subscribe to Mother Earth News.
I did almost buy this one about ten years ago, custom architect designed passive solar. Wall of windows facing south, a sort of multistory atrium effect with masonry walls. Interior shutters to let heat into the residence when wanted, and out at night when not. Two high efficiency wood burning units, one soapstone stove below grade and one in a masonry fireplace with blowers and doors. The tall part on top is a small studio or retreat that serves as a heat chimney in hot weather, just open the windows up there, and open the windows in the basement, voila, cool air circulating. Sellers claimed it maintained 58 degrees in winter with no heat and 75 in summer with no air. The square footage on Zillow is wrong. It’s twice that size.
In some ways I regret that I didn’t buy it. But, it’s still substantially below selling price in 2005, so I’m probably better off.
Self ping
There's really no "technology" or moving parts involved - that's why it's called "passive". No solar panels, no electricity, no water pipes. It is not meant to replace artificial means of heating and cooling - it supplements them.
It involves three important concepts that are really just common sense: the changing angle of the sun with the seasons; orientation of house and features (especially closets and other 'dead air' and windows); solar gain/ storage mass.
Here are the keys to making it work:
1. siting the house so that the long axis faces south or slightly east of south. If possible, the south side should be longer than the north. Our house was a symmetrical trapezoid.
2. minimizing glass on all sides but the south side, and placing 'dead air' like closets, hallways, etc. on the north.
3. design roof overhangs to shade the interior in the summer but allow light into the home in the winter(there's actually a calculation based on latitude). The equinox is the normal crossover point, but you can vary that depending on your local climate. In the South, we opted to have light enter the interior for a shorter period during the year.
4. build a "solar mass" (we poured a huge concrete cube that formed the dining room/ solarium floor) that will absorb heat during the day and radiate it at night
5. insulate like MAD - we framed up with 2x8s and 10s instead of 4s or 6s, and had additional R-MAX outside the studs as well. Roof was super-insulated, and ice dams are not a consideration here.
We had a conventional HVAC system, but it ran very little. Our total cooling costs for the hottest month in Georgia (the main consideration) hovered around $100 in the 1980s. We also had a manufactured fireplace and a whole-house ventilation fan that would pull the stripes off a pussycat.
So . . . in answer to your questions:
1. you let the furnace or the fireplace run a little more.
2. superinsulated roof helps a lot, shade helps a lot, you run the A/C a bit more but you don't need much.
3. there isn't any technology. That's the beauty of it.
My house, and most of the oldtimer’s houses in the north here were build for solar gain.
Because of care ful positioning of house and windows, I never have to fire up the woodstove until 400pm if temps are above 10 degrees and sun is predicted. One evening burn and one reload for the overnight. Day burns only on cloudy days. Not very cloudy here.
A bright sunny house really helps with the wintertime blues, too.
Wrong, passive solar just works. You still need some conventional heating and cooling, but passive will cover a high percentage of your heating and cooling even in extreme climates.
Oh yes it does, no shades curtains or blinds on my windows and the window trim is painted white.
The passive solar house that I almost bought back in 2005 (posted the Zillow listing for it on this thread) had a Trombé Wall, I’d just forgotten the name. South-facing wall of windows, a sort of tall atrium or greenhouse effect, with a masonry wall inside the glass. This house had usable square footage between the two, I’m recalling about six feet. Owners were using it as a sort of hanging greenhouse, growing vegetables out of season, floor was stone. A large stand of native oak blocked the sun in summertime. Interior openings with shutters in the masonry interior wall were used to further regulate heat gain or loss for comfort in the main residence. There was a vent in the peak of the gable that could be opened or closed to release or retain heat also. It was an unusual house and an unusually nice one, I suspect I’d have been happy with it.
thanx for all of the advice. i am using berms on teh windward side of the house...looking at geothermal heat...
anybody know anything about that?
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