Engineering topics

Horenstein, Mark N.

Publications and source records attributed to Horenstein, Mark N..

4 records

DOE OSTI2017

Performance Analysis of Electrodynamic Screens Based on Residual Particle Size Distribution

Dust accumulation on the optical surfaces of solar collectors causes significant losses in their energy yield. Fine dust particles, compared with coarse ones, contribute significantly more in the performance loss, assuming identical surface mass concen- tration. This study examines the performance of different electro- dynamic screen (EDS) prototypes, operated under different con- ditions, in removing fine dust particles in the laboratory environ- ment. After going through several cycles of dust deposition and cleaning using EDS, the dust residue left on each EDS prototype is collected and analyzed using a Horiba particle size distribution (PSD) analyzer. The PSD analyses determine which EDS design has performed superior in removing a given size range and in which operational condition. Here, the results are advantageous in the optimization procedure of EDS to attain maximum dust removal efficiency and minimum optical interference.

14 SOLAR ENERGY↗

DOE OSTI2017

Mitigation of Dust Impact on Solar Collectors by Water-Free Cleaning With Transparent Electrodynamic Films: Progress and Challenges

Energy-yield loss caused by soiling of photovoltaic modules and concentrated solar power (CSP) mirrors in utility- scale power plants installed in semiarid lands and deserts would result in unsustainable demands for fresh water needed for clean- ing. This paper reviews the progress of the electrodynamic screen (EDS) film technology for frequent water-free cleaning with low- energy requirements. Results presented here, based on laboratory- scale EDS-film-laminated solar panel cleaning, show that the output power can be restored higher than 95% of the initial power under clean conditions. For solar mirrors, the specular reflection efficiency can be maintained over 90% ensuring high efficiency of the CSP plants. Operation of the EDS film for main- taining high optical efficiency of solar collectors requires less than 0.2 Wh/ma 2 /cleaning cycle. Here, principles, optical modeling, construc- tion, lamination of the EDS films on modules and mirrors, and experimental data showing optical efficiency restoration without water consumption are presented. Lastly, current challenges in developing electrodes that would meet optical and conduction properties

14 SOLAR ENERGY↗

DOE OSTI2017

An experimental study on the characterization of electric charge in electrostatic dust removal

Automatic dust removal using the electrostatic forces of electrodynamic screen (EDS) is an emerging method for mitigation of energy yield losses caused by dust accumulation on solar collectors. Both electric field distribution and dust particles' charge acquired during the removal process play pivotal roles in thorough evaluation of EDS performance. Previous studies have comprehensively analyzed the electric field distribution in EDS. In this paper we have conducted a number of experiments to examine how two EDS design parameters, electrode width and inter-electrode spacing, and two operational parameters, applied voltage and relative humidity, affect dust particles' charge. Sixteen EDS prototypes in two sets were developed and tested in a laboratory environment to study the acquired charge by dust particles via charge-to-mass ratio measurements. It has been shown that the charge-to-mass ratio is directly affected by the electric field intensity on an EDS surface. Furthermore, we have shown the detrimental impact of relative humidity on EDS performance. Here, the results are advantageous in the evaluation of EDS design and its optimization to attain maximum dust removal efficiency.

14 SOLAR ENERGY↗

DOE OSTI2016

Electrostatic force distribution on an electrodynamic screen

The enormous potential of solar energy harvesting plants to provide clean energy is severely limited by dust accumulation on their optical surfaces. In lieu of the most commonly-practiced manual cleaning method of using high-pressure water jets, electrodynamic screen (EDS) technology offers an attractive solution for removing dust particles from optical surfaces using electrostatic forces. In this paper, the impacts of different EDS design parameters in the electric field distribution on an EDS have been studied. Furthermore, based on electric field expressions, closed-form solutions for multipolar dielectrophoretic (DEP) forces in the EDS application are provided. Detailed evaluation of the EDS performance necessi- tates investigation of different forces involved in the dust removal process. Different comparisons are made between repelling and attracting forces exerted on dust particles deposited on an EDS surface. These comparisons elucidate EDS performance in the removal of a given size range of dust particles. The significant detrimental impact of relative humidity upon the dust removal process is quantitatively addressed. As a result, it is shown how just a 10 percent increase in relative humidity can make the repelling force ineffective in the dust removal process.

14 SOLAR ENERGY↗