Hey Bill -
In 1996-97? I did a project for CDOT on Red Mtn #3 @ 13,200" el. Dry Rocky Mtn
snow.
We bolted the top of the array to the eve of the very small block building with
a welded framework to hold the [16] 75-watt {The biggies back then} .
As I recall we installed the modules at winter latitude plus 10 deg and never
had an issue somewhere around 58-60 degrees. Avalanches start at 32 deg+/- so
any movement should & did slide just fine.
We installed 13,200# of AGM [30 days of battery backup] and a SWWP air wind
generator, that lost its blades before the next spring, the anemometer lost its
cups at 200+MPH as the jet stream touched down at least once. Who would have
figured that one?
There was an LPG backup heater for the building, but it was not working by
spring [High winds? probably].
I have lost track of the project as state communication managers changed &
contact was not reestablished.
Overbuild, keep it simple, design for middle of the winter.
Back then we used relay style charge controllers, the previous system had blown
up all the previous CCs.
I allowed for 50% head room and we never lost another controller or fuse. We
were seeing over 45-50% additional gain at 13,200' elevation. 75 watt modules
were pushing 105-110 watts each. Kyocera LA 51? I think?
7000' would not be as extreme an enhancement.
Edge of cloud effect?, 7,000' elevation +20%+/-, reflection off the snow
10-15%, & -30F look at the temp curve and still give it another 10% of room.
Site visits in the winter @ these sites are slow all-day projects.
Dana Orzel Great Solar Works, Inc.
C - 208.721.7003 d...@solarwork.com
Idaho Contractor - # 028765 Idaho PV # 028374
NABCEP # 051112-136 www.solarwork.biz
"Responsible Technologies for Responsible People since 1988"
Please consider the environment before printing this email.
-----Original Message-----
From: RE-wrenches <re-wrenches-boun...@lists.re-wrenches.org> On Behalf Of
frenergy
Sent: Saturday, December 01, 2018 10:28 AM
To: re-wrenches@lists.re-wrenches.org
Subject: [RE-wrenches] Vertical PVs for Comm site
Sierra wrenches,
My 30 years of installation has never included comm sites on
mountain tops but I took the job.....
I am proposing mounting PVs vertically towards the top of the south wall of a 2
story block building to avoid snow build-up. I assume a pole-mount would be
next in line if we needed more sq ft of PV. However, even if vertical, will
Sierra snow (its a special breed) still wind-pack on, stay for weeks, days, not
at all? This site is on the Pacific crest at 7,000 ft.
And then due to potential temps down to -30F, I assume a WELL
insulated battery box (maybe even back-up heat?). It seems the best choice
would be to use AGM/VRLA/Gel? Part my reason for looking for help is my
customer's loads will only be 12 volt and wants to avoid the cost of an
inverter. This seems a little risky not to have an inverter/charger for
back-up. Appreciate the advice.
Bill
Feather River Solar Electric
Bill Battagin, Owner
4291 Nelson St.
Taylorsville, CA 95983
530.284.7849
CA Lic 874049
www.frenergy.net
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