POWER August 2014 - 22

4. Ground coverage ratio (GCR) affects performance
more than panel orientation. Results are based on data from
the Chowchilla, Calif., system. Courtesy: Exosun
■ Orien 30° ▲ Orien 20° ■ Orien 10° ◆ Orien 0°
2,120
2,100
2,080
2,060
2,040
2,020
2,000
1,980
1,960
1,940
◆
■
▲
■
◆
■
▲
■
◆
■
▲
■
30
35
40
Ground cover ratio (%)
Designing an Optimal System
Installers should be prepared to do their homework to find a
tracker that offers the ideal combination of affordability, performance,
and reliability. World-renowned certification bodies, from
Underwriters Laboratories to the Canadian Standards Association,
perform tests related to product safety, performance, and durability
in extreme environments. The highest quality trackers on
the market meet or exceed evaluation criteria in areas ranging
from accelerated aging to wind resistance, and are fully compliant
with safety-focused manufacturing codes. Strong product
Stop Abrasion
Damage!
Mineral based ceramic linings from
Kalenborn Abresist reduce the high
cost of maintenance for years in
pipes, cyclones, ducts, chutes,
flumes, conveyors, and fans.
Anything in your plant that
takes punishment from
abrasive materials
can be protected
with the appropriate
lining. Call, fax or visit
our website for information
and literature on the full line
of Kalenborn Abresist products.
45
50
5. Summer gains offset winter losses. Increased output
during summer months more than offsets lost production during the
winter, resulting in a total yield increase with trackers. Courtesy: Exosun
■
Exotrack HZ ■ Fixed-tilt
300
250
200
150
100
50
Jan. Feb. Mar. Apr. May June July Aug. Sep. Oct. Nov. Dec.
warranties also speak volumes to a tracker provider's commitment
to customers. If a PV system is expected to return dividends for
a minimum of 25 years, its trackers should be held to those same
standards of longevity.
Of course, smart system configuration is essential to achieving
maximum performance. As with any ground-mounted project, site
assessment begins with an evaluation of land size, cost, topography,
and weather patterns. When evaluating whether trackers are right for
a project, developers must weigh additional considerations.
An essential design aspect of tracker-equipped PV systems is
ground cover ratio (GCR), which is the ratio between the PV modules'
area and the total ground area. An increase in GCR negatively
affects system output (Figure 4). This is because the higher the
GCR, the smaller the distance between the tables, thus increasing
panel-on-panel shading. Unlike fixed-tilt systems, trackers with
an integrated backtracking program can position tables to avoid
shading adjacent panels.
Once we've selected the technology, site, and layout, it's time
for installation. The latest advanced trackers are far less cumbersome
and complex to install than their predecessors. High-quality
trackers offer a low-stress system, optimized for a fast and easy
installation process. Modular designs also significantly decrease
the amount of time, tools, and manpower required at a job site.
Seasonal Yield Variance
With a smart tracker system in place, PV plant developers and investors
should expect to see immediate financial benefits. Figure
5 shows the annual performance of the PV plant in Chowchilla,
comparing results with and without trackers installed. Fixedtilt
systems offer a minor performance advantage in the winter
months, when the sun is low in the sky, because a fixed-tilt installation
is always tilted toward the south. Single-axis trackers
follow the movement of the sun throughout the day; therefore,
tracker-equipped plants will achieve significant gains throughout
the summer. In this particular case, the average annual production
increase was 20.16%.
Solar tracker technologies have come a long way in recent years.
Kalenborn Abresist
5541 North State Road 13, Urbana, IN 46990
Toll Free: 800-348-0717 * Fax: 888-348-0717
www.abresist.com * E-mail: info@abresist.com
CIRCLE 13 ON READER SERVICE CARD
22
Today's solutions offer the simplicity and reliability PV plant developers
require, at a desirable price point. With the right tracker
technology and an optimized implementation, installers can offer
their customers a safe, long-term solar investment opportunity. ■
-Jay Johnson is vice president of business development for
Exosun Inc., a leading developer and supplier of solar tracking
systems.
www.powermag.com
POWER | August 2014
Specific production (kWh/kWpeak)
Specific production (kWh/kWpeak)
http://www.abresist.com http://www.powermag.com
POWER August 2014

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