Tilt angle optimization of photovoltaic modules considering the effect of dust

Abstract

This thesis presents a detailed discussion on the tilt angle optimization considering the effect of dust, the optimum cleaning frequency model with the estimated cleaning cost for PV modules in Bangladesh. Multiple research works have been carried out on finding the optimum tilt angles for PV arrays. Only few of them considered the effect of dust in the calculation. These works were based on experimental works where the PV modules were installed at different tilt angles and the optimum tilt angle was determined based upon the maximum power output of the dusty PV modules. Besides, the solar radiation model proposed by these works did not incorporate the effect of air mass. Moreover, the cleaning schedule for the solar PV modules was not addressed in any of the work. All of the reported works considered the desert environment and the seasonal dependency of tilt angle and the effect of rainfall were taken into account. In this work, Particle Swarm Optimization based mathematical model has been developed which includes air mass, elevation angle, average sunlight hour, transmittance and tilt angle of solar PV array. The equations for transmittance of PV array are developed including the mass of deposited PM10 (particles with diameter 10 micrometer or smaller) particle which was considered as dust due to availability of the data. The model parameters for different regions of Bangladesh are also determined on seasonal and yearly basis. The effect of rainfall and seasonal dependency of the tilt angles is also calculated by determining the equations of transmittance, the model parameters and the declination angles on seasonal and yearly basis. The effect of dust on the transmittance, efficiency and energy generation of solar PV modules are discussed with and without the effect of dust. The changes in yearly and seasonal optimum tilt angles with and without the effect of dust have been determined and the obtained results are compared with the published work. Contrasting to the previously published work, the problems of installing the PV arrays at higher tilt angles were also pointed out. Additionally, the clearness index for the eight divisional cities of Bangladesh are determined and compared with another published work. Finally, the cleaning cost and the revenue are determined on seasonal basis. The result of this work can be useful for the design of solar PV systems in Bangladesh.