Solar Powered Home
The solar powered home is not a new invention. Solar panels are pretty new because both solar electric panels
and solar hot-water panels only came into being over the past few decades.
But solar electricity and solar hot-water are only two of the possible forms of solar power that you can use in
your solar powered home. When the sunshine shines down on the walls and roof of your home and heats the surfaces
up, that's solar power as well. The trick is to have the right mindset to make use of it.
A solar powered home can de designed from scratch by the builder or architect to make use of that solar power
automatically. Much of the design of a solar house involves having a sold stone, concrete or compressed earth floor
which can absorb heat during the daytime and release that stored heat slowly at night.
The main windows of your solar-powered home need to be facing the sun at midday. (So in the USA and Europe,
northern hemisphere, the windows should face south. In the southern half of the globe - Australia, New Zealand,
South Africa and South America - the windows should face north for maximum sunlight.)
Having your solar-powered house allows the maximum amount of radiated heat from the sun to shine into your home
and heat up the floor. In homes already built without a solid floor, you can add thermal mass with large water
tanks inside the rooms that catch the light. These can be as simple as having several 50-gallon drums filled with
water (or 200 liter water drums). Alternatively you can have far bigger water tanks that are disguised as furniture
to make them look more acceptable to your guests and visitors - or you can have some kind of indoor rockery as a
feature, with or without plants. Even a large fish tank would help.
That takes care of heating in winter, but you don't want to be too hot in summer from all that radiated sunlight
and heat. Blocking out the summer sun isn't too difficult. A well-designed house can have eaves (a roof overhang)
which sticks out just enough so the winter sun gets into the house, but the hot summer sun does not. This works
because the angle of the sun in the sky is lower in winter - so the sun's rays can shine in under the eaves, but
the eaves will shade out the light from the summer sun, because it is angled high up in the sky.
You can also plant deciduous trees and shrubs on the sunny side of the house. Once they have grown to a decent
size, they will block the sun in summer. But in winter they drop their leaves, so the sun can get through. This can
also be achieved by installing a trellis with climbing vines or other plants on them that are densely-packed with
leaves in summer but bare in winter time.
The thicker your house walls are, the more thermal mass they contain as well. The thick walls of stone or
full-brick houses have good thermal mass... So do houses made of adobe, mud-brick or pisé construction (rammed
earth). The ultimate design for a solar-powered home is the Earthship.
An Earthship is a home made of rammed earth which has sun-facing windows on only one of its four sides. Not only
do they make an extremely solar-efficient home, but they are also designed to save all the roof-water into cisterns
in (or next to) the house. Usually they will have solar panels to create their own electricity, so they are
self-sufficient off the grid. What is more, they recycle their gray water - from showers and kitchen sink - into
indoor planters which provide thermal mass and fresh fruit and vegetables. Earthships are also designed to take care of their own sewerage disposal. Some designs have
waterless toilets, too.
The problem with Earthships is getting them accepted by your local building authorities, who have difficulty
understanding anything that is radically different. Michael Linton, the founder of the Earthship concept, has been
fighting for such acceptance for decades. But yes, Earthships are the best type of solar powered home that I have
personally come across!
References:
- PERMACULTURE A Designers' Manual by Bill Mollison, published by Tagari Books.
- EARTHSHIP Volume 1 (also Volumes 2 and 3) by Michael Reynolds.
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