<html><head></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">David's cost benefit analysis is similar to the calculation I perform for any customer considering tracking.<div>The shading analysis is the sticker. No sight has perfect solar access, and every hour lost needs to be included in your analysis.</div><div>The new software that goes with the Pathfinder does a good job of this. (Pathfinder Assistant)</div><div>However, you not only need to account for various spots on the array, but you need to take Pathfinder readings at all the different locations of the array, through the day, and through the year.</div><div>For a 2 axis tracking unit like the Wattsun, you need to begin to imagine a cloud of locations, and accounting for the losses accurately </div><div>gets harder, the more you think about it. How do you average all your points? (Calculus?) You have to do at least 2 sets of points (summer/ winter), </div><div>with at least 4 points for each set.</div><div>I found that the "worst case scenario" readings done on a first site visit, (bottom array corners, winter tilt) are way too conservative for a fair cost evaluation of tracking.</div><div>I'll do an initial fixed array analysis, if that looks encouraging, there's enough space, and the customer really is wanting tracking,</div><div>I'll do the more sophisticated shading analysis, (which I'm still trying to fully develop, help please?)</div><div><br></div><div>Happy NEw YEar,</div><div><br><div>
<span class="Apple-style-span" style="border-collapse: separate; border-spacing: 0px 0px; color: rgb(0, 0, 0); font-family: Helvetica; font-size: 12px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: normal; text-align: auto; -khtml-text-decorations-in-effect: none; text-indent: 0px; -apple-text-size-adjust: auto; text-transform: none; orphans: 2; white-space: normal; widows: 2; word-spacing: 0px; "><div>R. Walters</div><div><a href="mailto:ray@solarray.com">ray@solarray.com</a></div><div>Solar Engineer</div><div><br class="khtml-block-placeholder"></div><div><br class="khtml-block-placeholder"></div><br class="Apple-interchange-newline"></span>
</div>
<br><div><div>On Jan 3, 2010, at 12:35 PM, David Katz wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite">
<div bgcolor="#ffffff" text="#000000">
Since modules are getting so inexpensive, the big questions is what is
the best way to get 33% more power? Is it better to use 33% more
modules on a fixed array, or use a tracker? Which one costs less? It
costs $1.50 to $2.00 per watt for a tracker. If modules cost $3 per
watt and a fixed mount costs $.040 per watt , 33% of $3.40 per watt is
$1.12 per watt. And trackers don't come with a 25 year power output
warranty. I see tackers making sense when the array is powering a
centrifugal pump in the summer or possible a time-of-use grid tie that
pays more in the summer. You are definitely better off with more
modules on a fixed array in an off grid situation because you always
need more power in the winter when the tracker is least effective.<br>
David<br>
<br>
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<div class="Section1"><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">David Katz</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">Chief Technical Officer</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">AEE Solar</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">1155 <span class="SpellE">Redway</span> Drive</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">P.O. Box 339</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span class="SpellE"><span style="font-size: 10pt; font-family: Verdana;">Redway</span></span><span style="font-size: 10pt; font-family: Verdana;">,
CA 95560</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">Tel (707) 825-1200</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;">Fax (707) 825-1202</span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;"><a href="mailto:david@aeesolar.com">dkatz@aeesolar.com</a></span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 10pt; font-family: Verdana;"><a href="http://www.aeesolar.com/">www.aeesolar.com</a></span><span style="font-family: Arial;"><o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-family: Arial;"> <o:p></o:p></span></p><p class="MsoNormal" style=""><span style="font-size: 8pt; font-family: Verdana;">DISCLAIMER: <br>
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<br>
<br>
Dana wrote:
<blockquote cite="mid:002701ca8c9d$39eb5a80$adc20f80$@com" type="cite">
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<div class="Section1"><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: windowtext;">You
got it!<o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: windowtext;"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: windowtext;">It
boggles my mind to watch the two OB FM60s and see the difference each
day and
then to go back and see the data over time. It is a very good argument
for
tracking. We have a Durango client that we installed 12 KW GIT tracked
and it
is outperforming the expectations of our client too.<o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: windowtext;"><o:p> </o:p></span></p>
<div><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">Dana
Orzel<o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">Great
Solar Works, Inc<o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);"><a class="moz-txt-link-abbreviated" href="http://www.solarwork.com/">www.solarwork.com</a><o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">E
- <a class="moz-txt-link-abbreviated" href="mailto:dana@solarwork.com">dana@solarwork.com</a><o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">V
- 970.626.5253<o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">F
- 970.626.4140<o:p></o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">C
- 970.209.4076<o:p></o:p></span></p><p class="MsoNormal"><span style="font-size: 11pt; font-family: "Calibri","sans-serif"; color: rgb(79, 129, 189);"><o:p> </o:p></span></p><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: rgb(79, 129, 189);">I
will be the shift in how the world uses power! - Dana Orzel<o:p></o:p></span></p>
</div><p class="MsoNormal"><span style="font-family: "Arial","sans-serif"; color: windowtext;"><o:p> </o:p></span></p>
<div>
<div style="border-style: solid none none; border-color: rgb(181, 196, 223) -moz-use-text-color -moz-use-text-color; border-width: 1pt medium medium; padding: 3pt 0in 0in;"><p class="MsoNormal" style="margin-left: 0.5in;"><b><span style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">From:</span></b><span style="font-size: 10pt; font-family: "Tahoma","sans-serif"; color: windowtext;">
<a class="moz-txt-link-abbreviated" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">re-wrenches-bounces@lists.re-wrenches.org</a>
[<a class="moz-txt-link-freetext" href="mailto:re-wrenches-bounces@lists.re-wrenches.org">mailto:re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b>Allan
Sindelar<br>
<b>Sent:</b> Thursday, December 31, 2009 8:13 PM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Evergreen<o:p></o:p></span></p>
</div>
</div><p class="MsoNormal" style="margin-left: 0.5in;"><o:p> </o:p></p><p class="MsoNormal" style="margin-right: 0in; margin-bottom: 12pt; margin-left: 0.5in;">Dana,<br>
Thank you for this information. I would like to clarify what you wrote.
We have
long accepted that trackers may be expected to increase daily output by
about
35-40% in the summer and 10-15% in the winter, due to the differences
in the
sun's seasonal elevation and the resultant length of the solar day. It
sounds
as if you measured the effective increase from approximately summer
solstice -
winter solstice and got a 32% gain. You previously got the same gain
(33%)
measuring from last winter solstice to summer solstice. This makes
sense, as it
averages winter and summer gains over two roughly equal periods, with
variations (summer monsoons, etc.) being within acceptable error. <br>
And whether grid-tied, grid-tied with backup, or off-grid is irrelevant
as long
as you can compare and record the outputs of the two otherwise
identical
arrays, one tracked and one fixed.<br>
Do I understand this right? If so, it's good real-world data for design
purposes.<br>
Allan<o:p></o:p></p>
<div><p class="MsoNormal" style="margin-left: 0.5in;"><span class="il"><b>Allan</b></span><b>
Sindelar</b><span style="font-size: 10pt;"><br>
<a moz-do-not-send="true" href="mailto:Allan@positiveenergysolar.com" target="_blank"><span class="il">Allan</span>@positiveenergysolar.com</a><br>
NABCEP Certified Photovoltaic Installer<br>
EE98J Journeyman Electrician<br>
<b>Positive Energy, Inc.</b><br>
3201 Calle Marie<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a moz-do-not-send="true" href="http://www.positiveenergysolar.com/" target="_blank">www.positiveenergysolar.com</a></span><o:p></o:p></p>
</div><p class="MsoNormal" style="margin-left: 0.5in;"><br>
<br>
Dana Orzel wrote: <o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 14pt; font-family: "Arial","sans-serif"; color: rgb(31, 73, 125);">This
is for a grid tied with
battery backup Outback system.</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 14pt; font-family: "Arial","sans-serif"; color: rgb(31, 73, 125);">The
32% increased gain for the
tracker VS. fixed mount production is an average of the last 180 days
and I
checked it in the spring for the last 180 days [over the winter] and it
was
33%. The 12 – Evergreen 180 watt modules produce about 65 -70% of our
home and office’s electrical requirements.</span><o:p></o:p></p>
<div><p class="MsoNormal" style="margin-left: 0.5in;"><span style="font-family: "Arial","sans-serif"; color: rgb(31, 73, 125);">Thanks,</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="font-family: "Arial","sans-serif"; color: rgb(31, 73, 125);">Dana
Orzel</span><o:p></o:p></p>
</div>
<blockquote style="margin-top: 5pt; margin-bottom: 5pt;"><p class="MsoNormal" style="margin-left: 0.5in;"><span style="color: rgb(31, 73, 125);">Dana,</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="color: rgb(31, 73, 125);">That
32% is a very useful number, and it matches with our experience as
well. But I
need to verify a couple of assumptions, please:</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="color: rgb(31, 73, 125);">Does
this represent average annual production, rather than peak seasonal?
And is it
a grid-tied system?</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="color: rgb(31, 73, 125);">Thanks,</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="color: rgb(31, 73, 125);">Allan</span><o:p></o:p></p><p class="MsoNormal" style="margin-left: 0.5in;"><span style="color: rgb(31, 73, 125);"> </span><o:p></o:p></p>
<div><p class="MsoNormal" style="margin-left: 0.5in;"><span style="font-size: 11pt; color: rgb(31, 73, 125);">Allan Sindelar</span><o:p></o:p></p>
</div>
</blockquote><p style="margin-left: 0.5in;"><span style="font-size: 10pt; font-family: "Arial","sans-serif"; color: windowtext;">No
virus found in this incoming message.<br>
Checked by AVG - <a class="moz-txt-link-abbreviated" href="http://www.avg.com/">www.avg.com</a><br>
Version: 9.0.725 / Virus Database: 270.14.124/2596 - Release Date:
01/01/10
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