Performance characteristic of a PV module as influenced by dust accumulation: theory versus experiment

Abstract

This paper is aimed at assessing by theory and experiment the current–voltage and power-voltage characteristics of a PV module as influenced by dust accumulation. A method is proposed in a computer code to follow-up an incident solar radiation through the module layers considering the reflection and transmission of radiation at the interfaces between the layers to evaluate how the incident radiation is attenuated before reaching the module. Also, absorption of radiation in the dust layer and the glass cover is considered. The evaluation of the reflectance and transmittance calls for analysis of the accumulated dust to identify its constituents using X-ray fluorescence apparatus. The refractive and absorption indices are assessed for dust constituents as well as the corresponding effective values for the sample as a whole. The current–voltage characteristic of the dusty module is calculated using Simulink with consideration of module parameters after being corrected according to the incident radiation received by the solar cell and the ambient temperature where the module is installed. The calculated current–voltage and power-voltage characteristics of the dusty module agreed reasonably with the measured ones for a 175-W module as the incident radiation decreased to 68% due to dust accumulation with a subsequent decrease of the maximum output power of dusty module by 31% when compared with the clean one. The percentage decrease of short-circuit current recorded 31% due to dust deposition against 2% for the increase of open-circuit voltage at ambient temperature of 44 °C and incident solar radiation of 1027 W/m2. This conforms to previous findings in the literature.