Browsing by Author "Yang, Yifeng"

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    A comparative experimental study on the hydrodynamic performance of two floating solar structures with a breakwater in waves
    (Elsevier, 2024-12) Yang, Yifeng; Mi, Chenhao; Ou, Binjian; Wong, Anson; Duffy, John Gordon; Wood, Tim; Utama, IKAP; Chen, Wenchuang; Huang, Luofeng
    Floating Photovoltaic (FPV) is considered as a highly promising clean energy solution. In recent years, FPV has been widely deployed in calm water around the world. However, to find available space for further expansion, FPV needs to be deployed in seas whilst the oceanic waves significantly influence the structural stability and energy performance. On one hand, wave loads may cause structural fatigue and damage. On the other hand, wave-induced rotations of a floating solar panel will vary its tilt angle to the sunlight and thus affect the power output. To explore the new research field of ocean-based FPV, this work first designed a novel catamaran FPV floater with a four-point mooring system. Comparative experiments were then conducted in a wave tank to compare its seakeeping ability with a conventional flat-plate floater. Besides, a breakwater structure was further introduced to enhance the stability of these two types of floaters. Detailed data on floater motions and mooring line forces were collected under monochromatic wave conditions. Extensive analysis was performed to evaluate the wave-mitigating performance of the breakwater, as well as the nonlinearity in the motion and force time histories. Overall, the work provides valuable experimental data and novel insights into the design of FPV floaters and breakwater protection, supporting long-term sustainability of FPV on the ocean.
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    A symmetric experimental study of the interaction between regular waves and a pontoon breakwater with novel fin attachments
    (MDPI, 2024-12-02) Lyu, Xiangcheng; Yang, Yifeng; Mi, Chenhao; Tang, Chi Man; Adeboye, Lukman; Farhan, Mohamed; Collins, Stan; Ou, Binjian; Wong, Anson; Duffy, John Gordon; Huang, Luofeng
    Floating breakwaters are widely applied on the ocean water surface to protect human infrastructure from the destructive power of waves. This study designs and investigates the performance of a novel symmetric-pontoon floating breakwater with a symmetric pair of hydrofoils. Based at the Cranfield Ocean Systems Laboratory, the system was constructed and tested in various wave conditions using different fin configurations. The floating structure was anchored using a symmetric four-point mooring system. The tested waves were regular and symmetric perpendicular to the propagating direction. Key parameters, including the attenuated wave amplitude, motions of the breakwater, and the mooring forces, were measured. The wave parameters utilised for testing covered 1.61–5.42 relative wavelength to structural length, with wave heights of 3 cm and 5 cm. Results showed the 90° fin configuration can reduce wave transmission by up to 74%, with the lowest mooring forces at 3.05 relative wavelength, enhancing the performance of wave energy dissipation and structural seakeeping. At 90° setup, the mooring force was lowest at 2.41 relative wavelength. This research can inform novel designs of breakwaters to improve protection abilities for coastal cities and offshore infrastructures, especially renewable energy systems.
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    Floating PV systems as an alternative power source: case study on three representative islands of Indonesia
    (MDPI, 2024-02-05) Esparza, Ignacio; Olábarri Candela, Ángela; Huang, Luofeng; Yang, Yifeng; Budiono, Chayun; Riyadi, Soegeng; Hetharia, Wolter; Hantoro, Ridho; Setyawan, Dony; Utama, I. K. A. P.; Wood, Tim; Luo, Zhenhua
    Floating solar renewable energy is of enormous potential in Indonesia. This paper presents a comprehensive study of the design of Floating Photovoltaic (FPV) systems with Battery Energy Storage Systems (BESS) for three islands in Indonesia. These islands represent three typical scenarios in Indonesia (a) using a national grid powered by fossil fuel generators, (b) using a local grid powered by diesel generators, and (c) no grid at all. In-person surveys were conducted at these islands to collect data, and then FPV and BESS were designed to meet the demands of each island. Subsequently, the systems’ energy simulations were conducted using the System Advisor Model, demonstrating daily energy demand and supply in hour variation. Based on the results, a series of sustainability analyses were created from the aspects of economics, society, and the environment. The economic analysis demonstrated cost savings by using FPV to replace contemporary energy methods. The social analysis provides valuable insights into the local community, forming a demographic profile and obtaining perceptions and opinions regarding the new energy approach. The environmental analysis quantifies the potential CO2 emissions. Overall, the work provides valuable insights into the roadmap for implementing floating solar technologies in Indonesia which can also inform global ocean-based solar energy developments.
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    Floating solar power loss due to motions induced by ocean waves: an experimental study
    (Elsevier, 2024-11-15) Huang, Luofeng; Yang, Yifeng; Khojasteh, Danial; Ou, Binjian; Luo, Zhenhua
    Whilst there is an interest in floating solar energy systems in coastal and offshore regions to utilise available sea space, they are subject to ocean waves that introduce constant momentum. Consequently, solar panels undergo periodic motions with the waves, causing a continuous change in tilt angle. The tilt angle variation is a sub-optimal process and leads to a loss of energy harnessing efficiency. To investigate this phenomenon, the present study innovatively installed a solar simulator on top of a wave tank. The solar simulator was used to generate high-strength light beams, under which, a floating solar unit was subject to periodic incident waves. Wave-induced motions to the solar system as well as the output power were measured. A systematic analysis of the results indicated that a floating solar unit can have significantly lower power output in waves, compared to its calm-water counterpart. An evident link was established between the wave-induced power loss and the wave-induced rotational movement of the panel. An empirical equation was derived which shows the power loss is predictable through the rotational amplitude. The results also highlight the importance of implementing wave attenuation technologies such as breakwaters to minimise wave-induced motions to floating solar systems. Overall, this research presents a novel experimental approach to assess the difference of floating solar power in ocean-wave versus calm-water scenarios, providing valuable insights for future solar projects on the ocean.
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    Wave interaction with multiple adjacent floating solar panels with arbitrary constraints
    (American Institute of Physics (AIP), 2024-03-07) Yang, Yifeng; Ren, Kang; Zhou, Binzhen; Sun, Shi Yan; Huang, Luofeng
    The problem of wave interaction with multiple adjacent floating solar panels with arbitrary types and numbers of constraints is considered. All the solar panels are assumed to be homogeneous, with the same physical properties, as well as modeled by using the Kirchhoff-Love plate theory. The motion of the fluid is described by the linear velocity potential theory. The domain decomposition method is employed to obtain the solutions. In particular, the entire fluid domain is divided into two types, the one below the free surface, and the other below elastic plates. The velocity potential in the free surface domain is expressed into a series of eigenfunctions. By contrast, the boundary integral equation and the Green function are employed to construct the velocity potential of fluid beneath the entire elastic cover, with unknowns distributed along two interfaces and jumps of physical parameters of the plates. All these unknowns are solved from the system of linear equations, which is established from the matching conditions of velocity potentials and edge conditions. This approach is confirmed with much higher computational efficiency compared with the one only involving eigenfunction expansion for the fluid beneath each plate. Extensive results and discussions are provided for the reflection and transmission coefficients of water waves, maximum deflection, and principal strain of the elastic plates; especially, the influence of different types and numbers of edge constraints are investigated in detail.
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    Waves and structural strain induced by a uniform current flow underneath a semi-infinite floating solar coverage
    (American Physical Society (APS), 2024-09-20) Yang, Yifeng; Huang, Luofeng
    Floating solar panels installed on water reservoirs will be an increasingly popular renewable energy scenario. However, a significant current flow will occur when the reservoir gate is open to release water. Such a current flow can cause complex fluid-structure interaction at the edge of the solar panels, reversely analogized to a ship advancing through calm water, signifying the generation of a stern wave. This wave can damage the solar panels, which needs to be investigated to ensure operational safety. In this context, the present paper analyzes a mixed boundary problem of a uniform flow passing through a two-dimensional semi-infinite elastic plate using an analytical approach—the Wiener-Hopf technique. The mathematical model is based on the linearized velocity potential for fluid flow and the Kirchhoff-Love plate theory for an elastic plate. Three different edge conditions are considered here, namely, clamped, simply supported, and free. Extensive results and discussions are provided for the amplitudes of the propagation wave, and principal strain in the elastic thin plate. In particular, significant “resonance” fluid-structure interactions are found when the current speed is at certain special magnitudes. To support straightforward industrial applications, these special flow rates are given as a water depth Froude number. Overall, this study can provide valuable insights for floating solar projects on water reservoirs to control the water-release rate, thus minimizing the potential structural problems.