Laboratory simulation of the surface erosion of solar glass mirrors

Sand erosion of solar glass: Specific energy uptake, total transmittance, and module efficiency

“…However, the vast majority of the surface is filled with clustered textures containing adhering particles and scratch-like surface textures, which were unremovable by cleaning. Confirming Figure 6 and previous studies, 4,9,11,27 Figure 7 reveals the presence of shallow conchoidal fractures (1) and adhering particles (2), and large surface cracks (4). These phenomena can irreversibly deteriorate the efficiency of PV module by light scattering.…”

“…Sand and dust storms carry vast amounts of sand (>80 μm 1 ) and dust particles (<80 μm 1 ) already at wind speeds >14 km/h. [6][7][8][9][10][11] Wind speed and inclination angle are considered the most crucial parameters. 2 Thus, in these events, the efficiency of concentrating solar power plants and PV modules can be reduced by the deposition and accumulation of dust particles on the surface of the glass cover, known as soiling, 3 Abbreviations: d, diameter of the tube from the sandblasting device (m); e, kinetic energy of the mean sand particle (m/s); FF, fill factor (1); g, gravitational acceleration (m/s 2 ); I SC , short circuit current (A); L, distance between sand feeder and sample surface (m); m, mass of the mean sand particle (kg); M A , total sand mass impinged per unit area (kg/m 2 ); N A , total number of particles impinged per unit area (1/m 2 ); P in , input power (W); P out , output power (W); S P , particle speed (m/s); S Pexp , experimental speed of a falling steel ball (m/s); S Pth , theoretical speed of a falling steel ball (m/s); S W , wind speed (m/s); V OC , open circuit voltage (V); x, falling height (m); Δt, shutter time of a camera (s); Δx, length of sand particles traces measured from photographs (m); Δη, relative module efficiency decrease (%); α, impact angle between sand flow and glass cover (°); η S , efficiency of PV module (%) or by mechanical damage caused by sand particles (sand erosion) 4 or by abrasive mechanical contact cleaning.…”

“…5 Whereas soiling is usually reversible by cleaning, 3 sand erosion is not. 9,11 On the other hand, ductile materials exhibit a maximum erosion wear at low inclination angles of approximately 30°while brittle materials like glass exhibit a maximum erosion wear at 90°. [6][7][8][9][10][11] Wind speed and inclination angle are considered the most crucial parameters.…”

“…[6][7][8][9][10][11] Wind speed and inclination angle are considered the most crucial parameters. 11 This last finding is in contradiction with ref. In practice, sand particles up to 200 μm in diameter can be lifted into air at wind speeds >18 km/h, and particles >63 μm in diameter were found to be erosive at wind speeds >22 km/h.…”

“…Its irreversible effect is mainly controlled by local geoclimatic conditions like sand and dust storm probability, wind speeds, the nature of prevailing abrasive particles, and inclination angle. [6][7][8][9][10][11] Wind speed and inclination angle are considered the most crucial parameters. 6,8 As wind speed controls the speed and size of airborne particles, it is directly related to the kinetic impact energy.…”