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A team of scientists from China and the United States studied ways to optimize floating photovoltaic systems for use offshore. They found that the robustness of the systems was influenced by the size and number of platforms, as well as the types of connections between platforms.
Researchers from China and the United States have proposed a novel modular floating photovoltaic (FPV) solution to evaluate the performance of offshore multi-connection modules under combined wave and wind conditions. The team, consisting of scientists from Dalian University of Technology and the University of Maine, analyzed various types of fixed and articulated FPV systems to determine possible optimization approaches.
“The FPV is a complex multibody system subjected to the joint action of wind, waves, currents and other multiphysics fields,” the study states. “Therefore, it is of immense importance to develop robust engineering methodologies and models to design FPV systems applied to marine environments.”
The analysis revealed that as the number of modules increases, the motion responses become more pronounced, with the 2 x 2 platform experiencing the most significant pitch response of the configurations studied. The team also observed that the additional motion generated by the articulated connections led to a “non-negligible” dynamic response for multibody FPV systems, while systems using fixed connections did not show a significant dynamic response. Additionally, the researchers observed that the lashing tension of systems with hinged connections was higher than that of systems with fixed connections.
For this study, the group introduced a novel modular design for FPV platforms that incorporated the concept of semi-submersible ocean engineering platforms. It used a catenary mooring system, based on a curve that has been commonly used in mooring bridges, ships and ocean platforms. An offshore site in Shandong Province, China, was selected for the study, frequency domain analysis was used, and the overall hydrodynamic performance and behavioral characteristics of various types of FPV platforms were evaluated.
The researchers created the FPV platforms with cylindrical pontoons and oscillating plates. They mounted solar panels at a 10-degree tilt on steel trusses above the pontoons, with each steel truss providing at least 250 kW of power generation per platform. Motion responses under extreme conditions of tethered solo, 2 x 2, and 3 x 3 FPV systems were examined.
“The stability of FPV platforms is crucial to prevent the loss of power facilities caused by overturning and minimizes damage to power transmission cables,” they noted. “As a result, mooring design is critical to mitigating the dynamic response of FPV systems.”
The study highlights that the response to pitching is influenced by the relationship between mass and stiffness. The researchers observed that the maximum response to pitching of 2 x 2 FPV systems “is obtained when the wave depression is right in the connection position of the two modules and they have a V shape.” However, adding a third row of modules helped reduce relative motions, so that “the maximum pitching motion of the 3 x 3 platform” was less than the maximum of the 2 x 2 platform.
Based on their analysis, the team recommends an installation angle of at least 15 degrees for a multibody FPV system, in order to reduce both movement and structural responses.
The groups conclusions are available in the study “ Assessing the dynamic behavior of multiconnected offshore floating photovoltaic systems under combined wave-wind loads: A comprehensive numerical analysis ” : a comprehensive numerical analysis), published in Sustainable Horizons .
“Mooring systems could be optimized to further improve performance and reduce platform motion responses; These optimizations can lead to cost savings and make the system as a whole more economically viable,” they conclude. |
