dc.description.abstract | This study performed outdoor test of performance of the PV/CPV system in two areas (Jhongli and Pingtung), and PVsyst software was used to compare the measurements. In Jhongli, comparison of PV performance between two dual-axis sun-tracking systems (ephemeris calculation and light sensor) were made. The average offset angle of PV system based on ephemeris calculation was 0.89o, which is larger than that of light sensor (average offset angle was 0.3o). Although the former approach is less accurate than the approach of light sensor, but it can stably track the sun and does not affected by the weather. Meanwhile, the light sensor is easy affected by bad weather which prevent it function normally. Yet, the electricity output of the tracking PV system with ephemeris calculation is still better than the PV system using light sensor. For any PV system, electricity is the ultimate factor which decides the performance of PV. Thus, the approach of sun-tracking based on ephemeris calculation is a practical and effective sun-tracking method.
Results of I-V characteristic measurement of PV modules showed realistic performance of modules in outdoor tests. Under the same insolation, the increasing of module temperature causes rise of the short-circuit current and decrease of the open-circuit voltage, these decreased the overall electricity output and efficiency.
The CPV module uses the light sensor to track the sun. In bad weather condition, either clouds block the sun or strong diffuse irradiation will prevent the sensor to detect the sun, which degrade the power output of CPV module. Since the acceptance angle of CPV module is only 0.5o, and it only accept direct irradiation, therefore the CPV module have to use high accuracy tracker and order to maximize its effectiveness.
Since the irradiation directly affects the electricity production, the southern Taiwan has higher irradiation and PV electricity than that of the northern Taiwan. This study uses the same tracking PV with ephemeris calculation to install two system in Jhongli (northern Taiwan) and Pingtung (southern Taiwan), respectively. In the period of experiment (December 2012 to May 2013), the average final yield (Yf) for Jhongli and Pingtung are 76 kWh/kW and 95 kWh/kW, respectively. The average performance ratio (PR) for Jhongli and Pingtung are 0.85 and 0.9, respectively. The performance of tracking PV installed in Pingtung was better than that installed in Jhongli. This study was limited by short period of outdoor measurement of PV, and present experiment data was insufficient to decide the performance of both areas. To properly assess the behavior of PV in any location, Yf of longer time frame (one to several years) should be analyzed.
Due to the meteorological data directly affected the PV electricity production, this study uses two kinds of the meteorological data to simulate the electrical performance of the PV system in Jhongli and Pingtung. It was found that less error was obtained when using the real year meteorological data to simulate the PV system in Pingtung. As for the case of Jhongli, the error is smaller when using the average year meteorological data. Therefore, considering the appropriate type of meteorological data in the simulation of PV performance is important. | en_US |