Solar Panel Orientation
Daniel Shen
manually adjust the angle
of the solar collector three times a year? (This might not be
feasible for a super heavy collector.)
Just a thought off the top of my head.
Dan
== 1 of 5 ==
Date: Tues, Mar 20 2007 1:38 am
From: "Joe Rich"
No, not a simple one, but if someone has the space, I have an idea for
a cheap drive - use rear differential from cars / trucks.
I have been thinking of this for awhile - should be able to drive
quite a large panel with relatively simple motors. Just a thought.
Joe
On Mar 19, 6:17 pm, "Tony Luck" <tony.l...@gmail.com> wrote:
> On 3/19/07, Joe Rich <RichMan...@gmail.com> wrote:
>
>
>> The result of their estimate for clear air atmospheric attenuation
>> for
>> our latitude at local noon on December 21 is 742 watts/m^2, or -2.6
>> dB; for June 21 it is 962 watts/m^2, or - 1.4 dB (having designed
>> link
>> budgets for satellites, I think in dB).
>>
>
>
>> When one takes into account the cosine of the normal of the collector
>> and the sun angle, the losses throughout the day of a fixed collector
>> become quite high.
>>
>
> A Google search for "insolation san francisco" turned up some daily
> insolation tables for a few years. Ignoring the bad values near the
> solstices (as presumably cloudy days) I saw around 183 around the
> winter solstice, and 636 around the summer solstice. So yes, the
> low sun angle during the winter is measurably very bad for solar
> harvesting.
>
> I've seen repeated assertions on the internet that a tracking
> collector
>
Tony Luck
>
> What about having a mount with three settings where you could
> manually adjust the angle
> of the solar collector three times a year? (This might not be
> feasible for a super heavy collector.)
Getting somewhat close to the perfect angle has pretty
good benefits ... cosine(25 degrees) is around 0.9, so you
can get 90% of the benefit, with extremely approximate
tracking.
I've seen a few people on the internet with solar collectors
that they make occasional seasonal adjustments. When
Joe has his simulator s/w up and running perhaps he can
run some numbers for a system with a small number of
adjustments per year.
For a solar hot water collector, I'd need to see a really, really
cheap design for the *tracking* hardware though. Collectors
are cheap (compared with solar PV silicon[1]) so in many cases
it might be simpler to just add to the surface area by adding
more collectors, rather than add the additional h/w. Perhaps
this might be worthwhile if you invest in a fancy evacuated
tube collector?
-Tony
[1] and everything I've read says it isn't cost effective to make
tracking systems for PV either.