Passive Solar & Independence

Occasionally I go on a rant about how critical energy independence, energy decentralization and vernacular energy technology are to freedom. Or, how energy centralization creates empire. Every day I hear about how some new technology will save us from oil prices or pollution or whatever. What seems to be continually overlooked is how easily these problems -- and the danger of a solution that increases the centralization of energy production (nuclear...) -- can be solved: PASSIVE SOLAR.

I say this a lot, and I get the impression that the definition isn't really well known. There are those ugly solar photo-voltaic cells (ACTIVE solar) that you can put on your roof, but the energy required to make one (mainly derived from oil) is just about equal to the energy that they will produce over their lifetime, and they require centralized manufacturing and high-technology to produce. No, passive solar is simply the harnessing of the sun's power directly. Ever notice how a room with lots of windows that face the sun gets hot? OK, that's the whole concept... now let's explore how this can be applied effectively, simply, cheaply, etc.

Pretty much everyone can figure out how to heat a home with passive solar. But most people aren't aware at how effective passive solar can be for cooling, cooking, ventilation, waste disposal, etc. Let's take on the most difficult challenge: Cooling a home in Phoenix in the summer with only passive solar. Bill Mollison's "Permaculture: A Designer's Manual" outlines a passive solar cooling system which I have adapted into the graphic below.



For example, while in Phoenix it may never get below 90 at night during some points in the summer, the temperature of the earth at 10' underground is always a nice 55-65 degrees F. A simple solar chimney on your home (roughly, imagine a normal chimney x 50%, with a single-glazed window on the South side and a black-painted vent pipe inside) will heat up and pull air rapidly out of your home. Now, for air intake, lay a "radiator", a network of pipes 10' underground that acts as a heat-exchanger with the thermal mass of the earth. As the solar chimney draws air out, you get nice, cool air blowing in through vents in your floor. 0 energy cost, 0 moving parts, simple technology, and it keeps your (well insulated) home at a comfortable temperature and well ventilated, even in Phoenix in August. Similar technology has been in use in vernacular architecture in the Middle East for thousands of years.

Here's the catch: because it's vernacular technology, and can be easily implemented in a decentralized fashion, there isn't much money to be made off this through a centralized/industrialized economic mode. But it works... this is the very stuff of freedom.