Text Box: Technical Information

Last Updated:  Saturday, August 23, 2008

Technical Definitions and Information

For additional click the topics below. 

- Passive Solar (below)
- Solar Water Heating
- Energy Recovery Ventilator (ERV)
- Geothermal Heat Pump
-
Sun Path—Fairview, TX

Passive Solar – Passive Solar has a slightly different priority in the part of the country that we live in (near Dallas, TX). We are in a predominately hot and somewhat humid climate. We want to capture free heat from the sun in the winter, but our primary objective is eliminating unwanted sun in the summer.

We know enough about the movement of the earth relative to the sun that it is very easy to pinpoint exactly where in the sky the sun will be for any given minute of any day at any location on the planet. This location will vary over the months due to the tilt in the earth’s rotational axis. In the winter, the sun rises more in the Southeast and is low in the sky. In the summer it will rise in the Northeast and move high overhead.

By placing the walls, windows, and overhangs in the right location you can virtually eliminate any direct sunlight in the house during the summer and still gain a considerable amount of free solar heat in the winter. That's basically a passive solar design. The house just passively sits there and takes advantage of this natural cycle of sun movement.

¨ Keep shape square or rectangular – two story is more efficient than one

¨ Orient long axis east – west

¨ Place most windows on the north and south – minimize east and west glazing

¨ Install overhangs on the south windows per the guidance below

 

There are also other passive strategies such as the color and materials of the walls and roof. The insulation value and the thermal mass of the building must be considered also. Again, most of these items do not really cost any additional money. The require no maintenance, replacement, or additional care. A design that takes advantage of the solar cycle is really so simple and elegant that I can't believe that more people don't take advantage of it.

See the free: Passive Solar Design Guidelines

Further Reading

For additional information you might order books from the following lists:

Text Box: Right:  South facing windows can be shaded in the summer and gain heat in the winter if the overhangs are sized correctly.

Below:  Illustration of the way the sun varies with the seasons.  Avoid east and west windows for unwanted heat gain during the summer.
Passive Solar Books
Energy Efficiency Books
Text Box: If you find this free information helpful please make a small donation via PayPal

Click chart above for larger pdf file