All,
Thanks William for this! I love it when someone
comes up with a design parameter I've never
thought of. What would be great is if module
manufacturer's would include in their manuals
some quantitative data on how vertical and
horizontal shading swaths affect output.
Any data you have would be invaluable as I
imagine the rough ratio would apply to most
modules wired in the same way.
I've always done my interrow shading calcs
assuming any shading is bad and I think that
folks should still hold to this standard. It
really irks me when some big company new to solar
puts in a large ground mount array where they had
plenty of room to work with but they still use
the noon at Winter Solstice as their design input
for shading threshold angle. 9 AM- 3PM for a
couple of months surrounding that date and they
are throwing their power away for no good reason.
So I just hope that William's revelation doesn't
become an excuse for others to put rows closer in
landscape than good design dictates. I use 5ยบ
less than the Winter Solstice noon angle as my
shading threshold angle for most jobs. I
encourage folks to consider sticking to this kind
of standard whether landscape or not!
Best,
Jeff C.
Village Power Design
Friends:
We field tested the concepts this morning and
the answer is "yes" (inter-row shading in
portrait mode: bad -- in landscape mode: less
bad).
William
At 08:40 PM 4/22/2010, you wrote:
Friends:
99% of the time, we install modules in portrait
mode. We find ourselves installing a set in
landscape with some short inter-row spacing,
due to roof vents. We are using Solarworld
SW230 modules.
It is my understanding that shading the short
edge of this type of module is much more
detrimental to the output than shading a long
edge. This is because of the manner in which
the cells within the module are arranged in
series. I understand that one string is on the
bottom half of a module and the other on the
top half of a module in the landscape
orientation. In order for the module to cease
power production, you have to shade at least
one cell from each of the two internal strings.
Therefore, you need to shade more than half of
a module in the landscape mode before the
module before the output declines drastically.
Is my understanding here correct? I will be
testing this tomorrow if weather permits.
Thanks in advance.
William Miller
Please note new e-mail address and domain:
William Miller
Miller Solar
Voice :805-438-5600
email: [email protected]
http://millersolar.com
License No. C-10-773985
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
No virus found in this incoming message.
Checked by AVG - www.avg.com
Version: 9.0.814 / Virus Database: 271.1.1/2829
- Release Date: 04/22/10 11:31:00
Please note new e-mail address and domain:
William Miller
Miller Solar
Voice :805-438-5600
email: [email protected]
http://millersolar.com
License No. C-10-773985
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive:
http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
--
~~~~~~~~~~~~~~~~~~~
Jeff Clearwater
Senior Design Engineer
Village Power Design
Solar Design Consultation for the Commercial Sector
http://www.villagepower.com
[email protected]
Voice: 831-427-2799
Fax: 413-825-0703
245 Dufour St
Santa Cruz, CA 95060
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
_______________________________________________
List sponsored by Home Power magazine
List Address: [email protected]
Options & settings:
http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
List rules & etiquette:
www.re-wrenches.org/etiquette.htm
Check out participant bios:
www.members.re-wrenches.org
