Polycrystalline silicon photovoltaic (PV) modules have the advantage of lower manufacturing cost as compared to their monocrystalline counterparts, but generally exhibit both lower initial module efficiencies and more significant early-stage efficiency degradation than do similar monocrystalline PV modules. For both technologies, noticeable deterioration in power conversion efficiency typically occurs over the first two years of usage. Estimating PV lifetime by examining the performance degradation behavior under given environmental conditions is, therefore, one of continual goals for experimental research and economic analysis. In the present work, accelerated lifecycle testing (ALT) on three polycrystalline PV technologies was performed in a full-scale, industrial-standard environmental chamber equipped with single-sun irradiance capability, providing an illumination uniformity of 98% over a 2 x 1.6m area. In order to investigate environmental aging effects, time-dependent PV performance (I-V characteristic) was evaluated over a recurring, compressed day-night cycle, which simulated local daily solar insolation for the southwestern United States, followed by dark (night) periods. During a total test time of just under 4 months that corresponded to a year equivalent exposure on a fielded module, the temperature and humidity varied in ranges from 3 degrees C to 40 degrees C and 5% to 85% based on annual weather profiles for Tucson, AZ. Removing the temperature de-rating effect that was clearly seen in the data enabled the computation of normalized efficiency degradation with time and environmental exposure. Results confirm the impact of environmental conditions on the module long-term performance. Overall, more than 2% efficiency degradation in the first year of usage was observed for all thee polycrystalline Si solar modules. The average 5-year degradation of each PV technology was estimated based on their determined degradation rates.
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机译：与单晶光伏组件相比，多晶硅光伏（PV）模块具有较低的制造成本的优势，但是与类似的单晶PV模块相比，多晶硅光伏组件通常显示出较低的初始模块效率和更显着的早期效率下降。对于这两种技术，功率转换效率的显着下降通常发生在使用的头两年。因此，通过在给定的环境条件下检查性能退化行为来估计PV寿命是实验研究和经济分析的连续目标之一。在目前的工作中，在配备单光辐照能力的全尺寸，工业标准环境室中对三种多晶PV技术进行了加速生命周期测试（ALT），在2 x 1.6m范围内提供98％的照明均匀度区域。为了调查环境老化的影响，评估了随时间推移的PV性能（I-V特性），该性能是在一个反复压缩的昼夜循环中进行的，该循环模拟了美国西南部每天的日照量，然后是黑夜。在总计不到4个月的总测试时间（相当于现场模块一年的等效暴露）下，根据图森的年度天气概况，温度和湿度的变化范围是3摄氏度至40摄氏度，以及5％至85％ ，AZ。消除数据中明显可见的温度降额影响，可以计算出随时间和环境暴露的归一化效率下降。结果证实了环境条件对模块长期性能的影响。总的来说，在使用的第一年中，所有多晶硅太阳能电池组件的效率都下降了2％以上。根据每种光伏技术的确定降解率估算其平均5年退化。
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