On May 25, 8:22*am, Martin Brown
wrote:
On 25/05/2012 00:20, Andrew Gabriel wrote:





In articleiKidnQeYlsPqJCPSnZ2dnUVZ8vudn...@brightvie w.co.uk,
* *writes:
House fitted with 4KW of solar panels

In brilliant sunshine, such as we have had over the past couple of days,
what prevents solar panels producing the full permitted 4KW. Down to 2KW
now.

A few days earlier, when not as hot, solar panels were producing 3.73KW.

Angle of the sun (time of day).

Dust on the panels (my car seems to have a thick layer of yellow
pollen or sand which has built up over a few hot days of non-use).

Of course, there's also the possibility of a fault.

Also, it's light, not heat, which generates electricity.

And crucially heat decreases their efficiency although not normally by
factors of two. You should measure peak output when the sun is aligned
with the axis of your collectors (roughly same time each day).

Then you have a comparable number. It is possible you have a dodgy panel
that is misbehaving under thermal stress or they are covered in pollen
and dust at the moment.

Any partial shading of the array severely compromises output.

--
Regards,
Martin Brown- Hide quoted text -

- Show quoted text -

The inclination of the PV panels deemed best is for maximum annual
production. If they were any steeper, ey might work better in Winter
but Summer /overall production would be reduced.

The inclination of solar thermal panels deemed best is that for
maximum Winter production.
Because any surplus in Summer cannot be exported as with electricity.

However I have seen them (PV) performing at max with sun quite low in
the sky when the sky has been very clear. (Eg, after heavy rain has
cleared all the atmospheric moisture.)