Thursday, December 18, 2008

The solar works

In the loft
The solar panels are connected to an inverter (right - click photos to enlarge) , which converts the DC generated current into AC, using the "only clever bit" of the entire installation, according to the installer. This is mounted just inside the entrance to the loft. The interesting thing about the blue box is the "knock interface"... to switch on the unit and light up the screen you have to knock on the grey area. The screen tells you how many watts the panels are generating, and how much have been produced during the day, and how much in total.

In the kitchen
Downstairs, next to the consumer unit is a fantastic red knob, which isolates the panels. Above it is a meter which also shows how much electricity has been generated by the panels in total. During the first day of operation, the unit generated a total of 700W - disappointing considering it was bright sunshine outside all day, and the unit is spec'd at 1000W per hour. The installation engineer reassured me that as the sun got higher during the summer months the unit would generate much more - we shall see! During the second day of operation, when it was cloudy, the unit generated a total of just 200W during the day. Not good.

The electricity meter has been switched to an import / export meter. The meter gives the amount exported to the National Grid (ie total produced by the solar panel minus total consumed at the time in the house), and also the amount imported from the Grid. You can see the current cost clamp in the picture. This is interesting, because the current cost meter measures the flow of electricity regardless of which way it flows... so it reads 100W when the house consumes 100W, and it reads 100W when the house exports 100W. It was highly confusing turning on a light to see the amount on the meter decrease! So one of my Christmas projects is to connect another meter to the solar panel cable, and add the two readings together in order to get a sensible output... more on that later.


Anonymous said...

I'm a tad late in commenting here (just catching up on my reading now I'm feeling slightly better)...

All sounds most excellent, except the disappointing figures on generation of course. Lets hope come the summer you'll be equally as pleased with the amount you're generating.

We've been discussing Solar PV at home again prompted by the new series of "It's not easy being green" on BBC 2. We're not sure whether we're going to stay in our current house long enough to reach the payback period though so it's just not worth it. I look forward to a time when PVs are a bit cheaper, heard anything more about the printed panels coming to market yet?

Kevin X Brown said...

Hi Graham, I've not seen anything about printed panels on the market yet, just in research - could be a while yet. Did you see the IBM Research solar panel breakthrough?

I wonder if anyone would be prepared to pay more money for a house with solar panels on the roof?