| Summary: | 碩士 === 國立東華大學 === 光電工程學系 === 103 === The optical design of concentrated system using optical components to collect sunlight and transfer high energy to a multi-junction solar cell is a key technology to achieve high conversion efficiency. It possesses the potential to reduce system cost while keeping high conversion efficiency. The effect of concentrated spots and non-uniform exposure is often happened in current concentrated photovoltaic (CPV).
In this study, we have discussed a new designed high concentrated photovoltaic (HCPV) with a secondary optical element (SOE) to improve the conversion efficiency. The I-V characteristics of HCPV have been measured either under a light simulator or under outside sun radiation. The outdoor sun radiation measurement in eastern Taiwan results show that equivalent sunshine hours (E.S.H) from 2012 to 2014 are 3.19 hrs, 3.38 hrs and 3.47 hrs respectively, which are all more than 3hrs. It can be inferred that it is in line with the conditions to set up solar system in the Hualien area is good. We also find the relationship between straight light and diffuse light of the amount of sunlight. Due to the high intensity of sunlight at noon time, the diffuse rate only of about 20%. The result shows that noon time are suitable for HCPV power generation. For Si-base solar cell modules set up with different directions, we find testing results and simulation results have the same trend for years power generation. The results show that the suitable directions for arranging the solar cell modules in eastern Taiwan areas are in the directions between horizontal and south-title 23.5°.
Finally, we use a SOE on the HCPV to improve the uniformity and efficiency. The advantage of SOE is that it provides good uniformity in light exposure which enhances conversion efficiency. The results show the improved conversion efficiency of CPV without and with SOE is from 35.9% to 40.0%. The fill-factor of CPV are also on the rise. It means that the improved uniformity of illuminance on solar receiver by using SOE. It will be helpful for future HCPV applications.
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