Solar Power

Going Solar: Installing a Tracking 
Photovoltaic Array
Thomas Elpel has been asked more times than he can count if his owner-built, energy-efficient, stone and log home is off the grid and solar powered.

"Well no," he says, "we've always been on the grid, using electricity from coal-fired power plants and local hydroelectric projects. But we made finally made the leap into solar power and, as of January 1st, 2003, we have been producing our own power. We installed a 2528-watt photovoltaic (pv) array on two Zomeworks Passive Trackers to produce almost all of the electricity we use."

In a nutshell, Elpel Explains, the Zomeworks Passive Trackers are built with two large Freon-filled tubes welded from heavy square stock. There is one tube on each side of the tracker, with a small, flexible tube connecting them. Reflectors on the trackers help to focus solar energy on one of the square tubes while shading the other one. The Freon warms and expands, causing it to flow through the flexible tube to the other side of the tracker. That makes the other side of the tracker heavier, causing the panel to move and align itself with the sunshine. This way the panels track the sun all day long without using any electricity and without using any motorized systems that might break down.

Elpel’s PV system is grid-tied, consisting of sixteen 158-watt Kyocera solar panels, so that in the daytime it runs the meter backwards, powering other people's homes with his solar electricity, and at night he draws off the grid, using coal-fired power.

"On average we generate about as much electricity as we use," says Elpel, author of Living Homes: Integrated Design & Construction.

He lays out all the details about the costs and benefits of going solar on his website.