HI all look at solmetric.com I find most of the time PVwattsd is OK but I feel in some envoroments it is off, I really like the work by Solmetric Darryl
--- On Tue, 10/6/09, Joel Davidson <joel.david...@sbcglobal.net> wrote: > From: Joel Davidson <joel.david...@sbcglobal.net> > Subject: Re: [RE-wrenches] orientation data > To: "RE-wrenches" <re-wrenches@lists.re-wrenches.org> > Date: Tuesday, October 6, 2009, 3:35 PM > Hello Nik, > > We installed two 4 kW DC PV systems on a Sacramento PV > Pioneer home. Both arrays were tilted 18 degrees > with one array facing south and the other facing west. > The power from both systems fed into the Sacramento > Municipal Utility District grid (not the home). After 2 > years, SMUD reported (but did not provide data) that > the west-facing system produced 20% less energy than the > south-facing system. However, PVWATTS estimates the > difference to be 11.8% less. My experience with > hundreds of systems is that PVWATTS is a reliable > estimator for crystalline silicon PV systems if you factor > derating properly. It will be interesting to hear what other > wrenches have to say. > > Joel Davidson > > > > > > > From: > "Nicholas Ponzio, Building Energy" > <npon...@buildingenergyus.com> > To: > RE-wrenches <re-wrenches@lists.re-wrenches.org> > Sent: > Tuesday, October 6, 2009 10:37:32 AM > Subject: > [RE-wrenches] orientation data > > Hey Folks, > > Anybody have real data to compare productions for > south-facing vs, west-facing PV array? PVWatts is only > showing about a 7% derating for facing west. > > > Thanks, > Nik > > > -----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
