Evaluating the performance of PV modules in buildings (BIPV/BAPV) and the soiling effect in the UAE desert setting

Abstract

This paper assesses the performance of photovoltaic (PV) technologies integrated into buildings in the desert climate and the factors that affect energy yield. Cadmium telluride (CdTe) and standard monocrystalline silicon (c-Si) modules were installed facing south, in the three more common tilt angles used in the Building Applied Photovoltaics (BAPV) and Building Integrated Photovoltaics (BIPV) applications at the Dubai latitude (90°, 25°, and 0°). We monitored the energy production, the temperature of the PV modules, irradiance on each tilt angle, and the meteorological parameters for a full year. We then calculated the performance ratio for the six modules to evaluate the different factors, including temperature and soiling losses, following IEC 61724-1. The 25° modules, usual PV rooftop angle, had the highest and more consistent energy yield throughout the year. Conversely, the energy yield of the 90° modules, typical angle for facades, vertical shading devices, and guardrails, had the lowest yield and showed wide variations. This is expected as the 90° angle is more affected by the seasonal changes of the solar altitude. The soiling losses on these modules were lower than 1%. However, at 0°, the soiling loss was more evident, with an average reduction of 10.79%. The c-Si module at 25° generated the highest normalized energy yield of 402.02 kW h/m 2 , which was 23.5% more than that of CdTe module with the same tilt angle.

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“…Meanwhile, the variation in the results for different façade orientations came from the seasonal changes of the solar altitude in Al Ain city. But on the other hand, the soiling losses on the vertically mounted modules are usually lower than 1% where dust does not accumulate on them as it does on the tilted modules and when the modules are regularly cleaned each 10 days [25]. As the total average of the estimated electricity output from all of the BIPV modules reached about 60,197 kWh/year, it 'theoretically' exceeds the estimated 58,300 kWh/year yearly average electricity consumption of the tested model house.…”