Dust removal from solar concentrators using an electrodynamic screen

• Published in: Solar energy 2019-07, Vol.187, p.341-351
• Main Authors: Chen, Chia-Yang, Chesnutt, Jennifer K.W., Chien, Chih-Hsiang, Guo, Bing, Wu, Chang-Yu
• Format: Article
• Language: English
• Subjects: Adhesion; Charged particles; Cleaning; Computer simulation; Concentrators; Configuration management; Configurations; Discrete element method; Dust; Dust control; Dust mitigation; Electric field strength; Feasibility studies; Gravity; Particle adhesion; Particulate flow; Solar energy; Transport; Traveling waves; Water resources
• ISSN: 0038-092X; 1471-1257
• DOI: 10.1016/j.solener.2019.05.044

•Electrodynamic screen mitigates dust problems on concave solar concentrators.•High electric field strength and low adhesion lead to the best performance.•Particles hopping high (>1 mm) above the surface are not removed efficiently.•Rolling along the surface is the dominant particle motion for effective transport.•Cleaning efficiency is greatly improved with the sidestep configuration. The electrodynamic screen (EDS), which transports particles by electrodynamic waves, is a promising technology to repel deposited dust from solar devices in places where water resources are scarce. As gravitational force may impede dust removal on concave or parabolic solar concentrators, this study aimed to determine the feasibility of the EDS to transport dust either upward or laterally, for application to concave solar devices. A discrete element method was used to computationally simulate the transport, collision, and adhesion of charged dust particles that were subject to traveling waves on an inclined EDS. High electric field strength (>2 kVp-p mm−1), short distance between electrodes, and a low adhesion circumstance resulted in the best cleaning efficiency with a wave that traveled up the incline. Over half of the particles moved up the incline successfully under this operational condition. To improve the cleaning efficiency, a new EDS configuration wherein the wave transported particles laterally along the surface (instead of up the incline against gravity) was proposed. With the new configuration, the performance clearly improved in all cases. Although some particles moved down the incline under most conditions, the application of EDS to clean dust off solar concentrators is achievable with optimal parameters.