This is a funny thread as I spend some of my time doing commercial
installs in Hawaii, where tracking and tilt adjust is definitely not
happening, and you're lucky to get the panels facing even close to
south. The rest of the time though, I'm working with off grid
customers that some may actually track azimuth manually by loosening
the bolts on their top of pole rack. Tilt adjust in New Mexico for
off grid is pretty important, as we have short but intense winter
days followed by lots of snow that doesn't slide off unless you have
at least 40 degree tilt.
Also, I've run the numbers for Wattsun trackers with grid tie, and
the economics pencil out in favor of tracking. (PV Watts lets you
compare the benefits for your area)
If there is actually unobstructed area for tracking (very rare) I ask
the customer if they're interested. If they seem mechanically
inclined and like the idea, I might do it.
But if its a little old lady, who doesn't want to mess around, I set
everything for a year round setting, and never look back.
BTW, I once tried Unirac's roof mount with tilt adjust: very flimsy,
and hard to work with.
R. Walters
Solarray.com
NABCEP # 04170442
On Aug 13, 2009, at 2:36 PM, Ezra Auerbach wrote:
I so totally agree - during the winter there's not enough sun to
make a difference where we tilt the modules, and in the summer we
dump power anyway so we've set them for a nice spring/fall angle
and forgot about them for the last decade of so. The funny part is
I spent all kinds of extra dollars on my racking so it could adjust
it seasonally and through the day too. Never have done either with
this racking simply not worth the trouble.
Ezra
DragonSun Consulting
On 13-Aug-09, at 11:25 AM, Jeff Yago wrote:
I realize your client is set on doing this, but I installed
adjusting tilt racking on the 5 kW solar array I installed on my
home over 15 years ago and I can tell you after the first year of
adjusting these heavy sections I finally selected an average
position and they have not moved in 14 years.
I know there is a drop in the "calculated" performance between my
fixed mount and a semi-yearly tilt adjustment, but when you take
into account all the variations in weather, temperature, cloud
cover, system load, and battery state of charge, which are not
under our control, will impact system performance far more than
this tilt concern.
I say pick the best tilt angle that matches the season of year
that has the most system loading and forget about installing a
high cost adjustable mounting that most likely will never be used.
Jeff Yago
_____________________________________________________________
Netscape. Just the Net You Need.
_______________________________________________
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
_______________________________________________
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
