Solar Heating Up -- Nature Power: Energy From The Sun Can Be Harnessed To Heat Homes, Provide Lighting And Even Mow Lawns
Back in the late '70s and early '80s the hot word in high-tech home design was solar. Fueled more by the oil embargo than by the sun, hundreds of Northwest homeowners built or remodeled homes to include active solar systems using the up-to-$4,000 in alternative-energy tax credits that were available on a $10,000 investment. Dozens of companies and individuals eagerly sold active solar hardware to heat buildings, hot water and swimming pools.
But when the tax credits died, solar cooled off rapidly.
"Solar homes of that era were glamorous and exciting," says architect Tom Lenchek of Balance Associates Inc., who designed many solar homes and who last year completed his own award-winning passive solar home near Seattle's Leschi neighborhood. "But at least in the Northwest, active solar systems really didn't make much sense without the tax credits because of our cheap electricity and limited sunlight."
Many of those pioneering homeowners don't even use their expensive solar systems today, says Mike Nelson at the Washington State Energy Office. Some never worked right. Others have broken down and the companies that built them are long gone. But solar power, particularly passive and photovoltaic solar design, does work in the Northwest, he says, and today, it's coming back in a big way.
For example, US Solar Roof in Bothell plans to market solar roof tiles next year that look like standard tiles, but have very efficient photovoltaic cells built into them. Photovoltaics directly convert sun energy into electrical energy. Like microchips, says company president Paul Rodriguez, "the cells are becoming far more powerful and far less expensive all the time."
Solar-powered products such as hot water heaters, yard lights, calculators and battery chargers are becoming relatively common. Photovoltaics now power emergency telephones and lights in many remote locations. There's even a new $2,000 lawn mower, the Robotic Solar Lawn Mower, produced by A.B. Electrolux of Sweden that promises to mow your lawn by itself, powered by the sun.
As for home design, passive solar, which uses large areas of glass and the features of a building to provide heating, cooling and natural light, works quite well in the Northwest, because it works on cloudy as well as sunny days.
Passive design avoids "active" solar collectors (like those installed on roof tops) which need electricity and pumps to circulate heated water or other liquid between the collectors and the interior of the house.
Properly designed passive systems absorb maximum heat in the winter because of the sun's low position in the winter sky, which fully exposes the windows to the sun's rays. In summer, the sun is higher in the sky and the roof or other features of a solar house help shield the glass, greatly reducing the heat picked up.
"When I came to Seattle, seven years ago, people said solar just didn't work here. I could find almost no one doing it," says Chris