| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 98 === The purpose of this study is using finite element analysis (FEA) to investigate the effects of gravity and wind loads on the structural deformation and concentrator misalignment in a 5-kW high concentrated photovoltaic (HCPV) system. Several operation conditions, including no wind and wind speeds of 7, 12, and 37.5 m/s blowing to the front side and back side of concentrator arrays, were applied to simulate the stress distribution and structural deformation in the given solar tracker. The concentrator misalignment caused by the structural deformation was also calculated. An estimation of fatigue life was made for the given solar tracker under cyclic operation. A comparison of the simulation and measurement results of strain change at two selected locations in the given solar tracker during field operation was made to validate the constructed FEA model. A reasonable agreement of the simulation and measurement results was found such that the constructed FEA model was validated to be effective in assessment of the structural integrity of an HCPV system.
No structural failure was predicted for all the components in the given solar tracker under the loading conditions of gravity alone and plus a wind speed of 7 or 12 m/s according to the von Mises failure criterion. However, the von Mises equivalent stress in some components of the given solar tracker was larger than the yield stress at some zenith angles for a wind speed of 37.5 m/s such that a structural failure (plastic deformation) was predicted. An agreement in the trend of variation of misalignment and resultant displacement of Fresnel lens in each concentrator was found. Therefore, the concentrator with a greater misalignment could be readily identified from the corresponding displacement distribution. Given the conditions of no wind and wind speeds of 7 and 12 m/s, the maximum concentrator misalignment was 0.3 degree for a wind speed of 12 m/s blowing to the front side of concentrator arrays and it was within the range of an acceptance angle of 0.4 degree for the given concentrator. An estimation of fatigue life for the given solar tracker is 5.8 × 10 to the power of 10 days under a wind speed of 12 m/s. In this regard, no fatigue failure was predicted for the given solar tracker under a normally cyclic operation condition.
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