Modeling of Trajectories in an Electrodynamic Screen for Obtaining Maximum Particle Removal Efficiency

An electrostatic self-cleaning panel for solar collectors is described. An electrodynamic screen (EDS) is formed by interdigitated transparent surface electrodes energized by three-phase low-frequency ac voltages in the range of 5-200 Hz and 500-1000 V. The resulting electrostatic field wave exerts force on the particles and sweeps them laterally across the panel. Particle trajectories are simulated to help ascertain parameters for maximum dust-removal efficiency. The electric field of the EDS is found by a Fourier expansion of Laplace´s equation solutions for a surface potential that is periodic in space and time. Trajectories are found for particles of various sizes and charges and for different electrode spacings and excitations. Computed trajectories are compared qualitatively to experimental observations. One unexpected result is the chaotic behavior of larger particles which jump sporadically back and forth and only slowly migrate in the direction of the imposed electrostatic surface wave.