Nick,
Depending on the hours that the shadow is on the module, that indeed
may be the case. I have a similar circumstance with a recent Enphase
installation too: the shadow of a triplex service cable about 6 feet
away shadows the lower half of the array from sunrise until 7:00 am (in
the summer it won't last as long but in the winter it'll last longer).
During the time in question, the power output is reduced by nearly 20%,
yet the energy output for the day is only reduced by 0.2% because the
shadow doesn't last long and it occurs at a time when the power output
is low. The effect on energy production depends on how large the
shadow is, how long it lasts, and what hours it occurs.
Kent Osterberg
Blue Mountain Solar
Nick Soleil wrote:
Hi
Kent:
I am sure that aerial wires have very little impact on system
outputs. I just checked the Enphase Enlighten data for a system I
recently installed, which had a 1-2" to 3/4" wire bundle running just
5' above a solar modules. The wire cast a distinct shadow on the
module in question, but upon reviewing the output of that module,
compared with all other modules at the same orientation, I have found
that there is absolutely no effect on the production. I am surprised
that I can not even see any difference. That module has always
produced within 99% of the other modules on that roof, and the total
output of that module is as high or higher than the other modules!
Nick Soleil
Project Manager
Advanced Alternative Energy Solutions, LLC
PO Box 657
Petaluma, CA 94953
Cell: 707-321-2937
Office: 707-789-9537
Fax: 707-769-9037
From:
Kent Osterberg <k...@coveoregon.com>
To: RE-wrenches
<re-wrenches@lists.re-wrenches.org>
Sent: Thu, September
9, 2010 9:38:55 AM
Subject: Re:
[RE-wrenches] Wiley Asset
Benn,
At 25 ft a 1-inch power line subtends an angle of 0.2 degree. The sun
subtends an angle of 0.5 degree, so the power line will not make a
dark shadow on the modules - only 50% of the light can be blocked.
Depending on the distance from the module to the wire, along the ray to
the sun, the wire will probably block a little less light. But a 50%
reduction in the light on a few cells will probably reduce the entire
module output by 50%. A shadow every day for the hours you are talking
about sounds like a pretty serious issue.
Kent Osterberg
Blue Mountain Solar
benn kilburn wrote:
Thanks
for the feed back guys, much appreciated!
Now, how would you calculate for power/phone lines running
thru
the Pathfinder's reflection. There are about 6 of them (the largest
being at least 1") at least 25-30 ft away directly east of the proposed
array location, and they are running straight north-south. On the
Pathfinder they run btwn 9 and 11am in June and btwn 10:30 and 11:30 in
December.
Would the pathfinder software, suneye or asset pick up on
utility lines at that distance? How much effect do they have on
available sun output? And while i'm at it, how much do the 'software'
tools pick up on the tips of leafless tree branches at say 25ft, 50ft?
i'll try out that spreadsheet idea, nice one!
cheers,
benn
DayStar Renewable Energy Inc.
780-906-7807
HAVE A SUNNY DAY
Date: Wed, 8 Sep 2010 20:05:08 -0700
To: re-wrenches@lists.re-wrenches.org
From: will...@millersolar.com
Subject: Re: [RE-wrenches] Wiley Asset
Benn:
A colleague has used the Wiley took and calls it 'marginal.'
I use the Pathfinder and I like the features Ray described. I wrote
a very simple spreadsheet using the teeny numbers on the month lines to
create 100% of any month. I highlight and delete any of the numbers
that are shaded and the remainder is the percent of exposure for a
given
month. You can multiply the output of PV watts or any other
production result for a complete production prediction. Easy and
free.
William Miller
At 05:38 PM 9/8/2010, you wrote:
I've used the Pathfinder for
decades, so I'm partial to them. Great for on-site discussions of
shading
issues with the customer, as multiple people can see the shading at the
same time on the spot.
I've also used their Assistant software, and it works pretty well. You
take a photo of the actual pathfinder from above, and then download the
photo into their software.
You can then calculate total annual impact of any shading in Kwh, or
percentage of annual production.
I've been quite happy with the system, and the price for a Pathfinder,
and the software is much less than the Suneye, I believe.
R. Walters
r...@solarray.com
Solar Engineer
On Sep 8, 2010, at 3:46 PM, benn kilburn wrote:
Wrenches,
I'm looking at trying out another 'solar site evaluation tool', the
ASSET
(Acme Solar Site Evaluation Tool) from Wiley Electronics. I'm
looking for feedback on its performance and user-ability.
I have been using the pathfinder which is great, but not the pathfinder
software.
Any comments on the ASSET or Pathfinder software would be greatly
appreciated.
Cheers,
benn
DayStar Renewable Energy Inc.
b...@daystarsolar.ca
780-906-7807
HAVE A SUNNY DAY
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