Prediction of Optical Transmittance Loss In Solar Panels Using Lambert-Beer Law

The energy industry is extensively using the photovoltaic generators. The output of the panels during day time depends on various parameters solar irradiation, temperature, wind speed, humidity, fog and dust deposition, etc. In the outdoor photovoltaic generators under the natural weather conditions, the deposition of dust particles and pollutants reduce the energy efficiency. The deposition rate of dust particles are highly dependent on characteristics of the aerosol, humidity, wind direction, geographical location, tilt angle and cleaning time of panel. The dust density keep on increasing with the exposure time if cleaning is not done regularly. The dust covering the solar cell glaze leads to the degradation in the light beam optical transmittance, which causes the shadowing effect and reduction in the energy conversion efficiency. In the paper, particles with different dust densities are considered and reduction in the optical transmittance recorded experimentally and mathematically. In the study, dust particles of 4.2 to 1.4micrometer size are considered at different density level from 2g/m2 to 40g/m2. The paper provides the estimate of the number of particles present during different dust densities responsible for the optical transmittance loss. The results show that the transmittance is linearly decreasing in the initial dust densities, but after 20g/m2 the reduction is exponential and is followed by the saturation in transmittance. The result shows that the radius and density of the dust particles has a significant impact on the light beam transmittance.