You are currently browsing the monthly archive for August 2007.

Thirty-two days have expired since our 1.5-kilowatt solar-power system was installed on our Tulsa home’s roof.

It has generated 230.6 kilowatt hours of electricity.

That’s an average of 7.206 KWH per day. The system has done better than I expected, with the help of a lot of sunny and 8-plus-KWH days.

We’re still going to undertake a few projects to cut back on our power consumption. More on that later.

Advertisements

Since the 1.5 KW solar energy system was installed, it has generated 159.4 kilowatt hours of electricity in 295 hours of operation. That’s more than a half-KWH per hour. Pretty good.

Today, the system generated 8.32 KWH. It’s been going well over 8 KWH for the past four or five days because a high-pressure system sitting over Oklahoma. It’s been sunshine all day, with only the occasional cloud.

The solar panels continue to perform well despite temperatures in the high 90s. It’s my understanding that a solar panel’s performance tends to go down during hot weather.

In the past two days, I’ve conducted an experiment. During the heat of the day, I check the inverter readings, hose down the panels with cool water, then quickly check the reading again. I’ve read a lot of anecdotal evidence that solar panels will get a 10-15 percent production boost when you do this.

However, when I did it, the output rose less than 4 percent. I did this twice, and the modest increase was similar both times.

A recent conversation with John Miggins, owner of Harvest Solar, may reveal why. He said he once mounted solar panels an inch or two above the roof surface. But the roofs would get hot and hurt the panels’ performance.

With our house, Miggins decided to have the panels mounted a good four inches above the roof surface. This allows more air circulation around the bottom of the panels and thus keeps them cooler.

Combined with our light-colored roof shingles that reflect sunlight instead of absorbing it, our panels’ performance isn’t suffering much despite outdoor temperatures near triple digits.

That’s why it pays to have a solar installer who’s experienced and is willing to adjust his methods for the better.