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COMMERCIAL OFF-GRID
SOLAR ENERGY CASE STUDY
Off-Grid Commercial
Photovoltaic System
Chris Lanane, Air Monitoring
Specialist
Great Basin Unified Air Pollution Control District
“Apex Solar installed a 5.28KW solar power station in a
very remote location for the District. They did a great
job on the installation, were courteous to District
staff that were onsite, and professional in their
demeanor. Their knowledge of the equipment and its
operation was impressive. They were very willing to take
time to explain to the staff how the system was to be
installed and why and were very patient in training
District staff in the operation and maintenance of the
system. We, at the District, are very pleased with their
work and would hire them again for future solar power
equipment installations.”
See a larger photo
Description of Site:
The site is located at Mono Lake,
California. This is an extremely remote and harsh
environment. Summer temperatures extend into the high
80s and in the winter the temperatures can go into the
low 20s and winds can gust to 100 + mph. These winds
blow an acidic combination of sand and lake salts onto
the site. Accessing the site required the use of ATVs
and tracked vehicles due to the sand dunes and the soft
blowing sand conditions. The existing solar system that
was in place at the site showed signs of extensive
abrasion on the modules from blowing sand. All
electrical equipment had fine dust intrusion and was
failing due to the harsh conditions.
Customizing the System:
Apex Solar was to assist with
engineering and provide complete installation and setup
of the 5.28 KW solar power station. The air monitoring
equipment required 120 volt AC power 24 hours per day,
365 days per year. Carmanah was the supplier for all the
equipment installed and had developed a relationship
with the Great Basin Unified Air Pollution Control
District. Apex Solar worked closely with Carmanah’s
engineers to develop a system that would withstand the
high winds and the harsh environment.
Considerations:
The solar array was to be situated on a
level area of the sand dunes, 500 yards from Mono Lake’s
water’s edge. The site conditions required a number of
considerations. First, the modules had to be placed high
enough above the sand dunes so that the gusty winds
wouldn’t sandblast the modules. Second, the location
that the solar rack was to be placed was on very fine
sand and rack pull out due to loads on the module was a
serious concern.
See a larger photo
A third consideration was that due to
the temperatures extremes, the equipment and the
batteries needed to be placed in a stable environment
and kept as protected as possible from the blowing dust.
The ideal enclosure for the batteries and the equipment
was Zomeworks’s Cool Cell. The cool cell uses a
passively cooled enclosure that circulates water to keep
the interior at a stable temperature. Apex Solar
installed three (3) of the cool cell enclosures, two (2)
large battery enclosures (4’ x 4’ x 6’) and an equipment
enclosure (2’ x 2’ x 6’).
See a larger photo
The solar array was mounted on a
framework of 1 ½” schedule 40 steel pipe. The pipe was
driven by jack hammer into the sand at a depth of 5-6’.
To ensure that the leg mounts would not be pulled out
during high winds, Apex Solar installed earth anchors at
numerous locations that were connected to the rack with
steel cables.
System Specifications
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32 Sharp 165 modules
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24 GNB Absolyte IIP batteries
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2 Morningstar TS-60 charge
controllers
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Exeltech XP 1100 inverter
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Cool Cells From Zomeworks for
Battery and Equipment enclosures
Results of Installation:
This system was installed in November
2007 and has been operating maintenance free since
installation.
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