An engineer’s approach

An engineer’s approach

By Drs. Robert and Sonia Vogl, President and Vice President Illinois Renewable Energy Association

Dave Merrill of Byron has the distinction of owning the first residential pv installation and the first residential wind generator in the area. He also owns the first combination pv and wind generation system that is part of ComEd’s net metering program.

Combined pv and wind systems overlap in peak production very effectively. Illinois winds are reliable from fall through spring; pv is extremely productive during long, sunny summer days. Together, they provide a reliable system of electrical production.

A pv generating system almost takes care of itself. However, wind requires more work by the owner. Climbing to the top of a tower is a little more stress producing and strenuous than getting the ladder out to check the pv system on the roof.

A manufacturing engineer, Merrill “love(s) technology and tinkering with equipment. I played with electrical things since I was about 6 years old.”

In April 2000, he installed eight 75-watt Siemens panels, producing a total of 600 watts, on his roof. The panels are mounted on a rack with a motor-driven Power Point tracker that allows them to face the sun during the entire day for maximum efficiency. Shortly after sunset, the tracker re-sets itself and the panels again face east, ready for tomorrow’s sunrise.

The wind tower, producing up to three kilowatts (enough to power 50 60-watt light bulbs) of electricity, is homemade. The 80 foot high, self-supporting pole tower, similar to a street light pole, was purchased from spare supplies. The 14.5 diameter blades themselves were purchased ready to mount. The foundation is anchored into a cement slab with a 13-foot long by 3-foot diameter pole. Merrill scrubbed, painted, and applied rust protector to the parts while his father-in-law, a nuclear welder, assembled the structure. The job took one Saturday from 6 a.m. until 4 p.m.

A bank of 12 standard golf cart batteries completes the system. They store enough power to run the Merrill home for an entire day when grid power is interrupted.

“I love to save money,” admits Merrill. He does: While the average household uses 750 to 900 kilowatts of grid electricity per month, the Merrill home, complete with computers, TVs, all electrical and electronic equipment normally found in an average home, and teen-agers, uses 220 to 240.

While the pv system moves silently from east to west, the wind generator can whistle in the wind. Sometimes the noise makes Merrill nervous, wondering if the neighbors will worry. He has already calculated that the pole would not strike the neighbor’s garage or house if the worst happened and it fell in a strong wind.

“The neighbors did think I was strange at first,” he acknowledges. “But when there was a big game on TV, and everyone else’s electricity went out, I strung cords from my house to my neighbors’ houses, and they changed their minds!”

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