<html>
<head>
<meta content="text/html; charset=ISO-8859-1"
http-equiv="Content-Type">
</head>
<body text="#000000" bgcolor="#FFFFFF">
<div class="moz-cite-prefix">Jesse,<br>
Based only on the info you provided, I'd recommend the SE face. A
low slope is best for maximizing annual gain, which is what a
conventional grid-tie customer would want. But you are in essence
giving them a system that will function as GT now, but as an off
grid system if the grid goes down. Under that scenario, I would
sacrifice annual spin-the-meter-backward production in favor of
maximizing winter output, when days are shortest and loads are
greatest. A steeper array pitch will maximize available charge
during winter, while the shallow pitch will be great in summer but
close to nothing in winter. Given their stated objective, explain
the tradeoff as offering the best preparation for lack of grid.<br>
<br>
I'd advise otherwise if they clearly want to seasonally adjust
their array if there is an outage, and you install adjustable-tilt
racks, and the owners are afraid of neither ladders, heights, or
snow.<br>
<br>
We just completed a 4 kW GTBB system for a customer with similar
objectives. We used 16 240W modules on two 8-module pole-top
racks, with the instruction to leave the tilt angle shallow as
long as the utility is present, but tilt to 45-55 degrees in
winter during an extended outage. (And a pair of Classic 200s to
handle the 4-module series strings.)<br>
Allan<br>
<br>
<div class="moz-signature">
<meta http-equiv="content-type" content="text/html;
charset=ISO-8859-1">
<title></title>
<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a href="mailto:Allan@positiveenergysolar.com"><font
face="Times New Roman, Times, serif" color="#000099"><u>Allan@positiveenergysolar.com</u></font></a></small><font
face="Times New Roman, Times, serif"><br>
<span style="font-size: 10pt;">NABCEP Certified Photovoltaic
Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
Founder and Chief Technology Officer<br>
<b>Positive Energy, Inc.</b><br>
3209 Richards Lane (note new address)<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><o:p></o:p></span></font>
<p class="MsoNormal" style="margin-right: 722.25pt;"><span
style="font-size: 10pt;"><font face="Times New Roman, Times,
serif"><st1:place w:st="on"><st1:city w:st="on"></st1:city><st1:state
w:st="on"></st1:state><st1:postalcode w:st="on"></st1:postalcode></st1:place></font><b
style=""><br>
</b></span></p>
<span style="font-size: 10pt;"><br>
</span> </div>
On 5/14/2013 4:34 PM, Jesse Dahl wrote:<br>
</div>
<blockquote
cite="mid:E43E2313-9908-482A-BE64-F1512811F504@gmail.com"
type="cite">
<pre wrap="">Hello,
I was asked to look at a site today for a homeowner looking for a grid-tie with battery-back up. They are Doomsday Preppers for lack of a better term and want certain loads if and when the grid goes down for good. Aside from parts selection, they have two roof lines, one facing SE one facing SW. the SW is very low slope and is only accessible with a ladder and climbing on the roof, the other is SE, much steeper slope and accessible from the ground or deck. I mention the access because of snow removal. We had lots of snow last year and I spent lots of time on my roof removing 8" snow falls. Both have good solar access.
I'm inclined to chose the SE roof line, but I am interested in arguments for the SW.
Thanks!
Jesse
Sent from my iPhone
_______________________________________________
List sponsored by Home Power magazine
List Address: <a class="moz-txt-link-abbreviated" href="mailto:RE-wrenches@lists.re-wrenches.org">RE-wrenches@lists.re-wrenches.org</a>
Change email address & settings:
<a class="moz-txt-link-freetext" href="http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org</a>
List-Archive: <a class="moz-txt-link-freetext" href="http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org">http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org</a>
List rules & etiquette:
<a class="moz-txt-link-abbreviated" href="http://www.re-wrenches.org/etiquette.htm">www.re-wrenches.org/etiquette.htm</a>
Check out participant bios:
<a class="moz-txt-link-abbreviated" href="http://www.members.re-wrenches.org">www.members.re-wrenches.org</a>
</pre>
</blockquote>
<br>
</body>
</html>