On 24/11/2011 11:09, harry wrote:
On Nov 24, 10:52 am, The Natural
wrote:
harry wrote:
Thinking about it some more, it would depend very much on how ideal
their site was.
The weather in Scotland is against them but the panels shown are
rotating ones, (follow the sun) this makes a big difference.

No it doesn't.

I suppose it depends what you call a big difference. The geometry of
full solar tracking to maintain normal incidence in full sunlight gives
100% illumination - untracked but set at optimum declination gives about
63% (and you have to adjust with the seasons or suffer additional losses).

There is no advantage to tracking at all on cloudy days - and possibly a
slight disadvantage.

So there is a nearly 60% improvement in output by tracking the sun
continuously when it is shining - provided that the array does not
become self shading (which it will at low solar altitudes).

A better advantage on a ground based installation can be had by
surrounding the collector plates by non focussing flux concentrators and
providing active water cooling (ie. hot water supply out) to the backs
of the panels to keep them from cooking. Most could survive a 3-5x
increase in incident flux and generate additional power. Mirrors are
cheap by comparison to the panels. Non focussing technology also means
that PV output is also 3x higher on dull days too.

You cant get out of the fact that aveerage scottish insolation is less
than 100W/sq meter.

Ok angling them increases their effective 'sadow' but even so it aint
brilliant and the COST of MAINTAINING all those servo motors..

And they have to cope with the wind loading of the solar sails. Scotland
has some pretty juicy gales so it should be lots of fun.

I don't

see how they could get rotating ones for that money plus they take up
lots more space.
You would get more from the same sized panel compared to a fixed one.

But the very first sentence shows the bollock brain press in the
remark about "unplugging itself from the grid"

Dunno what the new FIT payment would be, it was £0.29 for a big
installation previously. The gov, site hasn't been updated.

Sounds about right.

As usual you are a f***ghalf wit.
If rotating didn't make any difference, they wouldn't make them.

Your faith in sales and marketing men telling the truth is touching. I
expect total cost of ownership of these active tracking solar panels to
be *insanely* high and predicted yields hopelessly optimistic.

The axis of rotation is not vertical either so the sunlight falls on
the panels at near 90deg.
Similar to astronomical telescope setup.

The picture shows them on vertical stalks. Are they really equatorially
mounted onto the poles? It doesn't look like it from the photos. And it
looks like they were at least installed at a sensible *SUNNY* latitude.

Regards,
Martin Brown