Look again at Assistant, you will find that Latitude is not indicated. Go to SunEye.com or (solmetric.com) they have a nice egg diagram that shows the best angle, you can also find the effect of tilt and Azimuth on peerformance.
Also there is a NREL software program that will calculate maxium payback. You are correct, the best angle is not Latitude, her in Minneapolis the best angle is 37 degrees/TMY3 and Solmetric. Also the solmetric PV design software is really excellent for design work. PVWatts can be sed to find the best angle. --- On Mon, 1/4/10, Drake Chamberlin <drake.chamber...@redwoodalliance.org> wrote: > From: Drake Chamberlin <drake.chamber...@redwoodalliance.org> > Subject: [RE-wrenches] Best angle - direct grid tie > To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org> > Date: Monday, January 4, 2010, 7:30 AM > > > Hello Wrenches, > > > My Solar Pathfinder Assistant (SPA) claims that the optimum > tilt angle > for the solar modules is latitude. I'm > skeptical. The system > being designed is a direct grid tie, ground mount. > > > It seems to me that an angle of latitude will give a > balanced angle for > both summer and winter charging. Since there is far > less energy > available in the winter, is this balance really the > best. Also, a > flatter angle in the summer should gain more hours of sun, > since the sun > goes N of the E-W axis. > > > With ballasted systems, the 15 degree angle is supposed to > work just > fine, due to better summer charging. Does anyone have > an answer to > what really is the optimum tilt angle for a direct grid tie > system? > Is the SPA geared toward off grid systems, or is latitude > really the > best? > > > Thank you and best wishes for the New Year, > > > Drake Chamberlin > > Athens Electric > > OH License 44810 > > CO License 3773 > > NABCEP TM > Certified PV Installer > > Office - 740-448-7328 > > Mobile - 740-856-9648 > > > -----Inline Attachment Follows----- > > _______________________________________________ > 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 > > _______________________________________________ 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
