Hi August, For what it is worth, Velux, one of the premier skylight manufacturers, limits the minimum angle of the roof (and the parallel skylight) to 15 degrees. With the roof windows/skylights the customer has direct observation of how much puddling and subsequent dirt is blocking the window.
Anyone care to estimate just how much performance is lost with 5-10 degrees off optimum tilt vs.no "ring around the collar" improved performance? Bill Loesch Solar 1 - Saint Louis Solar ----- Original Message ----- From: "August Goers" <[EMAIL PROTECTED]> To: "'RE-wrenches'" <re-wrenches@lists.re-wrenches.org> Sent: Tuesday, November 04, 2008 8:43 AM Subject: [RE-wrenches] Flat Panels > Wrenches - > > Lately we've been called out to repair or upgrade several ~5 year old PV > installations in the Bay Area. It is always interesting to see how they're > holding up. Apparently it was common to mount panels completely flat > (horizontal) on flat roofs back then. This poses a serious problem because > the module frame lip catches water and dirt and prevents the panel from > washing off in the rain. See a photo here: > > http://luminalt.com/temp/flatpanel.JPG > > > Note that two of those panels were broken by a baseball, but you can still > see the dirt buildup on the adjacent panels right across all three rows of > bypass diodes. > > Any ideas on what percentage loss that dried dirt is causing? > > Lesson learned: never tilt panels below 5 degrees, preferably 10 degrees. > > Cheers, > > > August Goers > > Luminalt Energy Corporation > > > _______________________________________________ > List sponsored by Home Power magazine > > List Address: RE-wrenches@lists.re-wrenches.org > > Options & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out participant bios: > www.members.re-wrenches.org > > > > -- > No virus found in this incoming message. > Checked by AVG. > Version: 7.5.549 / Virus Database: 270.8.5/1764 - Release Date: 11/3/2008 7:46 AM > _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
