Expanding R&D: optimizations for bifacial boost


SkySmart2 is the latest offering from Arctech Solar, which has 19 GW of cumulative mounting capacity installed throughout the world. The company’s suite of mounting products includes fixed-tilt structures and an impressive tracker portfolio. The tracker collection includes Arctracker Pro, featuring a push-pull design for flat sites, and SkyLine with one panel in portrait. It also includes SkySmart, which features two panels in portrait for challenging topographies. The company’s continuing design efforts include both structural engineering and software-based improvements and have been heavily backed by R&D investments.

Site challenges

The cost of site preparations can add heavily to the overall levelized cost of energy (LCOE) in locations where land is not flat and featureless. Two modules in portrait (2P) architecture means fewer posts than 1P trackers for the same number of panels, which improves the economics while simultaneously reducing grading volume. Arctech Solar has engineered its new SkySmart2 tracker design to minimize the need for ground preparation and to broaden the potential geographical market for 2P trackers.

“SkySmart2 was developed to be deployed in topographically constrained sites,” says Pedro Magalhães, Arctech Solar’s director of global engineering and R&D. “We also customize every single tracker project for the site conditions, optimizing each individual cross-section – it’s really project engineering customization.”

One key design feature of the new system is the high panel-to-post ratio. “With the two-in-portrait panel orientation on the SkySmart2, we can assemble 120 modules on just nine posts, for a substantial reduction in steel compared with the competition,” suggests Magalhães.

The two-in-portrait architecture also helps maximize the albedo or ground-reflected light because the panels are positioned away from the torque tube and are mounted higher with respect to the ground. “The 2P allows for a gap in between panels that prevents shading. The posts are also taller so the panels are placed at a further distance from the ground, whereas with the 1P design, there is always torque tube shading and the back surface is too close to the ground to really maximize the effect of reflected light,” Magalhães says.

But due to longer chords, 2P tracking systems have been challenged by dynamic instability under wind loading. The new Arctech tracker has been designed to avoid excessive rotation, which it says could cause torsional galloping effects. The company is in the midst of advanced wind tunnel testing of its trackers to help eliminate these challenges. With wind tunnel partner CPP, Arctech Solar is obtaining the torsional movement across the entire array field directly from the empirical wind tunnel test.

“Instead of analytical aeroelastic calculations, Arctech Solar and CPP use flexible tracker models, which mimic stiffness and damping ratios of trackers installed in the field. This is an innovative research step that Arctech is pioneering,” says Magalhães.

The proof of the company’s R&D-backed design efforts may be measured in market acceptance. The company says it has deployed approximately 2.2 GW of SkyLine and SkySmart tracking systems in the last two years.

AI augments performance

Arctech Solar’s more recent advances in software include a marriage of workhorse algorithms and self-learning artificial intelligence. Combining the potential gains in energy yield that such algorithms-plus-AI can present, the manufacturer hopes to improve overall energy yields by as much as 6%, according to Bruce Wang, CTO of Arctech Solar. “Our AI structure and solution is quite different from our competitors,” he explains.

One key use of AI by Arctech Solar is comparing orientation and shading within array sites that contain varied topographies. “If an array is on flat ground, you can readily calculate optimal orientation, but when an array is on varied topography with trackers at different heights, the problem is more complex,” Wang says. “So we sought to optimize the trackers in an array based on the actual height of the tracker tables.”

Another part of the complexity of calculating optimal tracker orientation is the broad number of variables affecting albedo when bifacial panels are utilized. “We are using AI to analyze the performance of different manufacturers’ bifacial panels with multiple sensor detection to optimize the control master for total yield output,” Wang says.

Similarly, Arctech Solar is harnessing AI to analyze the energy output from different manufacturers’ string inverters so that the entire array is optimized for yield. Wang adds that a third way Arctech Solar is using AI is in the comparison of different solar arrays within a cloud database.

Gathering all this data from different points in an array can be limited by the quality of the telecommunications technology employed within and among arrays. To enhance the practical distance of communication transmission and to reduce the number of collection or repeating points, Arctech Solar has adopted Long Range telecom (LoRa), while keeping Zigbee technology as an option.

Improving international standards

Arctech Solar has invested heavily in R&D over the past decade. The company set up a tracker test laboratory, authorized by TÜV SÜD, which became the first tracker test laboratory in China to be certified by a third-party organization.

The company’s ambitious R&D work with trackers has enabled it to become a driving force in the generation of new international standards under the auspices of the International Electrotechnical Commission (IEC) and the International Organization for Standardization. Arctech Solar has also been involved in several IEC initiatives, including its unique invitation from the group to join the IEC TC82 Working Group 7, which includes topics on safety, performance and testing of solar trackers.

“It is very important to promote international standards for trackers so that all suppliers meet minimum requirements,” concludes Wang.


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