<div dir="ltr">The analysis of 50% of south facing production is too simplistic; running some modeling shows that, depending on the latitude, the difference can be much smaller, approaching 25% less for the north facing. I think this layout could become more common especially on low slope commercial roofs, where the north facing module would occupy space that was already unused due to interrow shading. Of course the closer to the equator the less difference between production of the north and south arrays...and you better be careful when stringing them in series so as not to mix N and S facing..plus filling in all those gaps between rows could make servicing the array a bit problematic!<div><br></div><div>Cheers,</div></div><div class="gmail_extra"><br clear="all"><div><div class="gmail_signature"><div dir="ltr"><div><br></div><div>Brian Mehalic <br>NABCEP Certified Solar PV Installation Professional™ R031508-59<div><br></div><div><div>PV Curriculum Developer and Instructor<div>Solar Energy International<br><a href="http://www.solarenergy.org" target="_blank">http://www.solarenergy.org</a></div></div></div></div></div></div></div>
<br><div class="gmail_quote">On Tue, Jul 28, 2015 at 10:24 AM, <span dir="ltr"><<a href="mailto:billbrooks7@sbcglobal.net" target="_blank">billbrooks7@sbcglobal.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div lang="EN-US" link="blue" vlink="purple"><div><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Jarmo,<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">The sun’s geometry is not nearly that simple. To understand the impact of north-facing arrays, you have to perform a simulation. PV:WATTS does this just fine and it is easy to show that a 18-degreed North-facing tilt produces 75% of a perfect 30-degree south-facing array. Far more than your assumption of 50%.<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">To compare 15-degrees South to 15-degrees North, the numbers are slightly better at 77%. We are going to see a lot of north-facing arrays once people understand that low tilt angles are very forgiving on North slopes. Steep slopes are a totally different story and you have to run the numbers….<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Bill.<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> RE-wrenches [mailto:<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>] <b>On Behalf Of </b><a href="mailto:Jarmo.Venalainen@schneider-electric.com" target="_blank">Jarmo.Venalainen@schneider-electric.com</a><br><b>Sent:</b> Tuesday, July 28, 2015 8:04 AM<span class=""><br><b>To:</b> RE-wrenches <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>><br></span><b>Subject:</b> Re: [RE-wrenches] Using the North Facing Roof<u></u><u></u></span></p><div><div class="h5"><p class="MsoNormal"><u></u> <u></u></p><p class="MsoNormal"><span style="font-size:10.0pt;font-family:"Arial",sans-serif">I did a slide on the effect of North facing modules. For even a fairly aggressive rotation North as shown, the effect is "only" a 50% reduction.</span> <br><br><span style="font-size:10.0pt;font-family:"Arial",sans-serif">The questions of whether or not to do it, are,</span> <br><br><span style="font-size:10.0pt;font-family:"Arial",sans-serif">- is the mounting structure simpler, lower cost</span> <br><span style="font-size:10.0pt;font-family:"Arial",sans-serif">- security against wind</span> <br><span style="font-size:10.0pt;font-family:"Arial",sans-serif">- can I put a larger array on the roof (typically yes, if you make back to back pyramid shaped structures)</span> <br><span style="font-size:10.0pt;font-family:"Arial",sans-serif">- overall, what is the cost versus benefit</span> <br><img width="610" height="434" src="cid:image001.gif@01D0C916.96962470"><br><span style="font-size:10.0pt;font-family:"Arial",sans-serif">JARMO<br></span><span style="color:green">_____________________________________________________________________________________</span> <br><b><span style="font-size:7.5pt;font-family:"Arial",sans-serif"><br>Jarmo Venalainen</span></b><span style="font-size:7.5pt;font-family:"Arial",sans-serif"> | <b><span style="color:green"> Schneider Electric </span> | Xantrex Brand</b> | <b>CANADA</b> | <b>Sales Application Engineer</b> <b><br>Phone:</b> <a href="tel:%2B604-422-2528" value="+6044222528" target="_blank">+604-422-2528</a> | <b>Tech Support:</b> <a href="tel:800-670-0707" value="+18006700707" target="_blank">800-670-0707</a> | <b>Mobile:</b> <a href="tel:%2B604-505-0291" value="+6045050291" target="_blank">+604-505-0291</a> <b><br>Email:</b> </span><a href="mailto:jarmo.venalainen@schneider-electric.com" target="_blank"><span style="font-size:7.5pt;font-family:"Arial",sans-serif">jarmo.venalainen@schneider-electric.com</span></a><span style="font-size:7.5pt;font-family:"Arial",sans-serif"> | <b>Site:</b></span><a href="http://www.xantrex.com/" target="_blank"><span style="font-size:7.5pt;font-family:"Arial",sans-serif"> www.Xantrex.com</span></a><span style="font-size:7.5pt;font-family:"Arial",sans-serif"> | <b>Address:</b> 3700 Gilmore Way, Burnaby, BC V5G4M1 </span><u></u><u></u></p><table border="0" cellpadding="0"><tbody><tr><td colspan="4" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><a href="http://www.xantrexrebate.com/" target="_blank"><span style="text-decoration:none"><img border="0" width="1" height="1" src="cid:image003.png@01D0C916.96962470"></span></a><u></u><u></u></p></td></tr><tr><td style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><a href="http://www.xantrex.com/" target="_blank"><span style="text-decoration:none"><img border="0" width="166" height="55" src="cid:image004.gif@01D0C916.96962470"></span></a><u></u><u></u></p></td><td style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><a href="https://www.facebook.com/Xantrex" target="_blank"><span style="text-decoration:none"><img border="0" width="36" height="55" src="cid:image005.gif@01D0C916.96962470"></span></a><u></u><u></u></p></td><td style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><a href="https://twitter.com/Xantrex" target="_blank"><span style="text-decoration:none"><img border="0" width="38" height="55" src="cid:image006.gif@01D0C916.96962470"></span></a><u></u><u></u></p></td><td style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><a href="https://twitter.com/Xantrex" target="_blank"><span style="text-decoration:none"><img border="0" width="303" height="55" src="cid:image007.gif@01D0C916.96962470"></span></a><u></u><u></u></p></td></tr></tbody></table><p class="MsoNormal" style="margin-bottom:12.0pt"><br><br><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#00a000"><br>*** Please consider the environment before printing this e-mail</span><br><br><br><u></u><u></u></p><table border="0" cellpadding="0" width="100%" style="width:100.0%"><tbody><tr><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f">From:</span> <u></u><u></u></p></td><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif">"Peter Parrish" <<a href="mailto:peter.parrish@calsolareng.com" target="_blank">peter.parrish@calsolareng.com</a>></span> <u></u><u></u></p></td></tr><tr><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f">To:</span> <u></u><u></u></p></td><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif">"'RE-wrenches'" <<a href="mailto:re-wrenches@lists.re-wrenches.org" target="_blank">re-wrenches@lists.re-wrenches.org</a>>, </span><u></u><u></u></p></td></tr><tr><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f">Date:</span> <u></u><u></u></p></td><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif">07/28/2015 12:22 AM</span> <u></u><u></u></p></td></tr><tr><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f">Subject:</span> <u></u><u></u></p></td><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif">[RE-wrenches] Using the North Facing Roof</span> <u></u><u></u></p></td></tr><tr><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif;color:#5f5f5f">Sent by:</span> <u></u><u></u></p></td><td valign="top" style="padding:.75pt .75pt .75pt .75pt"><p class="MsoNormal"><span style="font-size:7.5pt;font-family:"Arial",sans-serif">"RE-wrenches" <<a href="mailto:re-wrenches-bounces@lists.re-wrenches.org" target="_blank">re-wrenches-bounces@lists.re-wrenches.org</a>></span><u></u><u></u></p></td></tr></tbody></table><p class="MsoNormal"><u></u> <u></u></p><div class="MsoNormal" align="center" style="text-align:center"><hr size="2" width="100%" noshade style="color:#a0a0a0" align="center"></div><p class="MsoNormal"><br><br><br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">I recently read a short piece that caught me up short, and I quote:<br></span><br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">“The fast dropping cost of solar, while a huge boon to the adoption of solar PV, has counter-intuitively altered design parameters. No longer is the north-facing roof considered unusable because limited application in less-than optimal orientations can still show a positive net benefit. Arrays are thus designed now with elements or sub-arrays in these locations, increasing overall kW installation while reducing the energy production per capacity installed. This might have been anticipated based on sheer economic analysis from a users perspective, but so long has solar been expensive that these less optimal orientations were never seriously considered.”</span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080"> </span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">I doubt that the individual who wrote this piece came to these conclusions him/herself. Does anyone know of a recent article that argued this perspective? Is this an emerging design practice? If so, I’d like to know more about it. </span><br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080"> </span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">- Peter </span><br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080"> </span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">Peter T. Parrish, Ph.D.</span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">President, SolarGnosis</span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">1107 Fair Oaks Ave., Suite 351</span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080">South Pasadena, CA 91030</span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080"><a href="tel:%28323%29%20839-6108" value="+13238396108" target="_blank">(323) 839-6108</a></span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080"><a href="mailto:petertor@pobox.com" target="_blank">petertor@pobox.com</a></span> <br><span style="font-size:10.0pt;font-family:"Calibri",sans-serif;color:#004080"> </span> <u></u><u></u></p><p style="margin-bottom:12.0pt"><br>______________________________________________________________________<br>This email has been scanned by the Symantec Email Security.cloud service.<br>______________________________________________________________________<tt><span style="font-size:10.0pt">_______________________________________________</span></tt><span style="font-size:10.0pt;font-family:"Courier New""><br><tt>List sponsored by Redwood Alliance</tt><br><br><tt>List Address: <a href="mailto:RE-wrenches@lists.re-wrenches.org" target="_blank">RE-wrenches@lists.re-wrenches.org</a></tt><br><br><tt>Change listserver email address & settings:</tt><br></span><a href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org" target="_blank"><tt><span style="font-size:10.0pt">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</span></tt></a><span style="font-size:10.0pt;font-family:"Courier New""><br><br><tt>List-Archive: </tt></span><a href="http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html" target="_blank"><tt><span style="font-size:10.0pt">http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html</span></tt></a><span style="font-size:10.0pt;font-family:"Courier New""><br><br><tt>List rules & etiquette:</tt><br></span><a href="http://www.re-wrenches.org/etiquette.htm" target="_blank"><tt><span style="font-size:10.0pt">www.re-wrenches.org/etiquette.htm</span></tt></a><span style="font-size:10.0pt;font-family:"Courier New""><br><br><tt>Check out or update participant bios:</tt><br></span><a href="http://www.members.re-wrenches.org" target="_blank"><tt><span style="font-size:10.0pt">www.members.re-wrenches.org</span></tt></a><u></u><u></u></p></div></div></div>
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