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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Enphase has a tech note pdf for download that recommends and
rationalizes a PV watts derate of .819 instead of the standard .77 (which IMO
is a little conservative to begin with). <o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><a
href="http://www.enphaseenergy.com/downloads/EnphaseAppNote_PVWatts.pdf">http://www.enphaseenergy.com/downloads/EnphaseAppNote_PVWatts.pdf</a><o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Kirk Herander<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>Vermont Solar Engineering<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>802.863.1202 fax 802.863.7908<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>VT RE Incentive Program Partner<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>NYSERDA Incentive-eligible Partner<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>NABCEP<sup>TM </sup>Certified Installer<o:p></o:p></span></p>
</div>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
<div>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";
color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:
"Tahoma","sans-serif";color:windowtext'>
re-wrenches-bounces@lists.re-wrenches.org
[mailto:re-wrenches-bounces@lists.re-wrenches.org] <b>On Behalf Of </b>Allan
Sindelar<br>
<b>Sent:</b> Sunday, April 18, 2010 3:18 AM<br>
<b>To:</b> RE-wrenches<br>
<b>Subject:</b> Re: [RE-wrenches] Tilt biased....<o:p></o:p></span></p>
</div>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='margin-bottom:12.0pt'>Holt,<br>
Feedback re the low tilt angle: Go for it, you're good.<br>
<br>
Re wind loading: check out UniRac's Code Compliant Installation Manual, <a
href="http://www.unirac.com/pdf/ii227.pdf">http://www.unirac.com/pdf/ii227.pdf</a>,
especially pages 3-9.<br>
<br>
Less wind loading is one of the main reasons for going with a lower tilt angle.
Another is closer module row spacing (at 3X height RoT) without inter-row
shading.<br>
<br>
No experience with Enphase.<br>
Allan<o:p></o:p></p>
<div>
<p class=MsoNormal><span class=il><b>Allan</b></span><b> Sindelar</b><span
style='font-size:10.0pt'><br>
<a href="mailto:Allan@positiveenergysolar.com" target="_blank"><span class=il><u>Allan</u></span><u>@positiveenergysolar.com</u></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 href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a></span><o:p></o:p></p>
</div>
<p class=MsoNormal><br>
<br>
<a href="mailto:holtek@sbcglobal.net"><u>holtek@sbcglobal.net</u></a> wrote: <o:p></o:p></p>
<div>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif"'>Searching
for opinions.....is this "over design"?</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif"'>Designing
small system (2.35kW). Customer uses gas for heating. Typical A/C unit. I was
thinking of biasing the tilt to summer production for greater offset of summer
demand (lat 31.6, proposing 18). No net metering in this part of
the world. PVwatts shows a drop of 2% /yr. in production , 5% higher
production for A/C months. Feedback?</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif"'> Also,
this array will go on a carport. I understand that windloading is actually
greater for an open structure than one with walls (another reason for lower
tilt) - is there any one that can direct me to data on finding out how much
more? </span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-family:"Calibri","sans-serif"'>Lastly,
what is a good avg. target derate factor for Enphase inverters (real world)?</span><o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
</div>
<div>
<p class=MsoNormal><span style='font-size:10.0pt'>Holt E. Kelly<br>
Holtek Fireplace & Solar Products<br>
500 Jewell Dr.<br>
Waco TX. 76712<br>
254-751-9111<br>
<a href="http://www.holteksolar.com"><u>www.holteksolar.com</u></a></span><o:p></o:p></p>
</div>
<pre><o:p> </o:p></pre><pre style='text-align:center'>
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