Contents lists available at ScienceDirect Solar Energy Materials and Solar Cells journal homepage: www.elsevier.com/locate/solmat Electrodynamic dust shield performance under simulated operating conditions for solar energy applications Bing Guo a, ⁎ , Wasim Javed a , Charles Pett b , Chang-Yu Wu b , Jonathan R. Scheffe b a Texas A&M University at Qatar, Doha, Qatar b University of Florida, Gainesville, FL, USA ARTICLE INFO Keywords: Photovoltaic soiling loss Dust Cleaning efficiency Electrodynamic dust shield Aerosol Cyclic operation ABSTRACT Electrodynamic dust shield (EDS) uses traveling-wave or standing-wave electrodynamic effects to repel dust particles from a surface, and has been proposed as a potential anti-dust solution for mitigating soiling loss in solar energy applications. In this study, a standing-wave EDS technique was tested in a cyclic manner at field- relevant dust loading levels using dust deposited by aerosol deposition, in order to assess the EDS’ dust removal efficiency under simulated real-world operating conditions. Tests using sieve deposition and the single-operation mode were also carried out for comparison. Each single-operation test only used freshly-deposited dust with a single activation of the EDS, and the results showed that the dust removal efficiency with aerosol deposition to be moderately lower than that with sieve deposition. In contrast, a cyclic-operation test consisted of many consecutive cycles, which began with the first cycle using freshly-deposited dust, and each additional cycle having new dust added on top of the persistent dust from the previous cycle. The cyclic-operation dust removal efficiency was found to be strongly dependent on the dust deposition method. Using aerosol deposition, the cyclic-operation efficiency continually decreased as the number of cycles increased; with sieve deposition, the cyclic-operation EDS efficiency fluctuated and had a much higher average value than with aerosol deposition. The different behaviors of the cyclic-operation EDS efficiency can be modeled with two hypothetical scenarios, based on how the persistent dust from a previous cycle reacts to EDS activation. However, the physical me- chanisms behind the different behaviors are not well understood. The results from this study suggest that further research is critically needed for evaluating the effectiveness of electrodynamic anti-dust solutions for solar en- ergy applications in dusty environments. 1. Introduction In dry and dusty regions, dust accumulated on critical surfaces of solar devices can block solar irradiation and cause significant loss in energy output, also known as soiling loss [1]. In dusty environments, a photovoltaic (PV) module can accumulate 80 mg m -2 –300 mg m -2 of dust per day, and every 100 mg m -2 of dust accumulation can cause an additional output loss of 0.4–0.7% [2,3]. Such high levels of soiling calls for active cleaning to maximize the economic return of a solar power generation project. Development of various PV cleaning tech- nologies has been active, and there is a need for standardized labora- tory test methods for evaluating these technologies, so that their tech- nical merits can be assessed under comparable conditions. Electrodynamic dust shield (EDS) has been proposed as a candidate for anti-dust solutions for solar power generation in recent years [4,5]. Initially developed for space applications, EDS is also known as elec- trodynamic screen, electric curtain, or electrostatic cleaning system [6–8]. As shown in Fig. 1, the basic EDS design involves fabricating electrodes on a substrate. The electrodes are either transparent or made very thin so as to minimize any shading effects, and they may be formed into straight lines or other more complex patterns [4,5]. Over the electrodes, a transparent dielectric cover is needed to isolate the elec- trodes from air. The dielectric cover becomes the outer most layer that requires soiling mitigation. When operating in the field, dust deposition occurs on the outside (air side) of the dielectric cover, but activation of the EDS can repel the deposited dust, taking advantage of the electro- static charges carried by the dust particles [9]. The dielectric cover is a thin sheet that is bonded to the electrodes/substrate through an ad- hesive, or applied as a coating [4,5]. Activating, or “energizing” the EDS, involves applying an alternating high voltage to the electrodes, which leads to an alternating electric field. Electrically charged dust that deposited on the air side of the dielectric cover can then be repelled from the EDS due to the alternating electric field. The EDS can either be a standalone thin structure that covers the front surface of a solar https://doi.org/10.1016/j.solmat.2018.05.021 Received 13 November 2017; Received in revised form 30 March 2018; Accepted 9 May 2018 ⁎ Corresponding author. E-mail address: bing.guo@qatar.tamu.edu (B. Guo). Solar Energy Materials and Solar Cells 185 (2018) 80–85 0927-0248/ © 2018 Elsevier B.V. All rights reserved. T