Allan, That is pretty much my thinking. They have 0 interest in stepping foot roof and the SE give more tilt and easy ground access to clear the array during winter.
I appreciate the advice. Jesse Sent from my iPhone On May 14, 2013, at 10:15 PM, Allan Sindelar <[email protected]> wrote: > Jesse, > 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. > > 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. > > 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.) > Allan > > Allan Sindelar > [email protected] > NABCEP Certified Photovoltaic Installer > NABCEP Certified Technical Sales Professional > New Mexico EE98J Journeyman Electrician > Founder and Chief Technology Officer > Positive Energy, Inc. > 3209 Richards Lane (note new address) > Santa Fe, New Mexico 87507 > 505 424-1112 > www.positiveenergysolar.com > > > > On 5/14/2013 4:34 PM, Jesse Dahl wrote: >> 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: [email protected] >> >> Change email address & 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: [email protected] > > Change email address & 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: [email protected] Change email address & 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
