Dew as a Detrimental Influencing Factor for Soiling of PV Modules

Ilse, Klemens; Figgis, Benjamin; Khan, Muhammad Zahid; Naumann, Volker; Hagendorf, Christian

doi:10.1109/jphotov.2018.2882649

Cited by 70 publications

(32 citation statements)

References 23 publications

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“…This process is illustrated schematically in Figure 12. Cementation has also been observed in desert environments where cool nights cause dew formation, trapping any dust within the condensed area [2,21,22]. High temperatures during the daytime then cause evaporation, leaving cementation to form on the surface.…”

Section: Cementationmentioning

confidence: 98%

Testing the Durability of Anti-Soiling Coatings for Solar Cover Glass by Outdoor Exposure in Denmark

et al. 2020

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The presence of soiling on photovoltaic modules reduces light transmission through the front cover glass to the active absorber, thereby reducing efficiency and performance. Current soiling mitigation techniques are expensive and/or ineffective. However, anti-soiling coatings applied to the solar cover glass have the potential to reduce soiling for long periods of time without continuous maintenance. This paper reports the performance of two transparent hydrophobic coatings (A and B) exposed to the outdoor environment of coastal Denmark for 24 weeks. A comparison was made between the performance of coated and uncoated glass coupons, periodically cleaned coupons, and accelerated laboratory tests. Although initial results were promising, water contact angle and transmittance values were found to decline continuously for all coated and uncoated coupons. Surface blisters, film thickness reduction, changes in surface chemistry (fluorine loss), and abrasion damage following cleaning were observed. Coupons cleaned every 4 weeks showed a restoration in transmittance. Cycles of light rainfall and evaporation combined with a humid and salty environment led to cementation occurring on all coupons. The development of an abrasion-resistant, super-hydrophobic coating with a low roll-off angle and high water contact angle is more likely to provide an anti-soiling solution by reducing the build-up of cementation.

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Section: Cementationmentioning

confidence: 98%

Testing the Durability of Anti-Soiling Coatings for Solar Cover Glass by Outdoor Exposure in Denmark

et al. 2020

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“…At night, the panel temperature is lower than exterior temperature due to radiation of the solar panel (Figure ). The lower temperature of the module surface can induce water condensation at the panel surface when the dew temperature difference with panel temperature is smaller than 5 K. The condensed water can strongly attach dust to the glass surface via cementation …”

Section: Resultsmentioning

confidence: 99%

“…Comparing the indoor and the field tests, a difference in efficiency can be observed. This could have various origins like (a) the improvement brought to new indoor electrodes compared with the field test generation, (b) the shape and size of the dust can be different from the tested sand, and finally (c) the cementation of the dust with the presence of moisture due to condensation, as this was not evaluated during the indoor test.…”

Section: Resultsmentioning

confidence: 99%

Field test and electrode optimization of electrodynamic cleaning systems for solar panels

Faes

Petri

Champliaud

et al. 2019

Progress in Photovoltaics

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Soiling is the major cause of power loss of photovoltaics (PV) and concentrated solar power (CSP) in desert areas. Electrodynamic cleaning system (EDS) is an automatic and water‐free integrated cleaning system for mirrors or solar panels, which uses pulsed electric fields to remove dust off their surface. The first EDS field test over a long period on PV modules is reported here and shows a clear effect on soiling reduction in real conditions in Saudi Arabia. A total of 458 days of measurements is analyzed, and depending on the considered periods, performance losses due to soiling (soiling rate) can vary from −0.06%/day to −0.41%/day for a reference module, while the relative soiling rate reduction using an EDS can be up to 95.7% with an average of 32.1%. Cost calculations demonstrate an added value of the modules equipped with the EDS between 2.6 and 5.2 ¢/Wp compared with usual cleaning system, which is nearly between 10% and 20% of the module price. In addition, extended indoor tests of various electrode designs of EDS for heliostat dedicated to CSP or PV applications show a high cleaning efficiency of up to 98% with front glass thickness of more than 1 mm. A good specular reflectivity, only 4% lower than the bare reference mirror, is obtained with patterned sputtered silver in a spiral electrode design. High reliability of two types of electrode deposition is demonstrated after 200 cycles between −40°C and +85°C.

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“…2 Relative humidity and dew strongly enhance dust adhesion to surfaces through capillary forces, particle caking, and cementation. 1,17,27,28 These moisture-related adhesion mechanisms are considered important, even in deserts: radiative cooling of the glass surfaces at night allows surfaces to cool below the ambient air temperature. They frequently reach the dew point, and thus, dew precipitates on the collector surfaces.…”

Section: Context and Scalementioning

confidence: 99%

“…They frequently reach the dew point, and thus, dew precipitates on the collector surfaces. 1,27 On top of reversible optical losses, soiling can cause permanent degradation of PV modules and mirror materials. In cases of omitted cleaning, cemented dust layers, lichens, and fungi can become practically irremovable, whereas harsh cleaning can lead to the scratching or abrasion of typical anti-reflective coatings (ARCs) or glass corrosion.…”

Section: Context and Scalementioning

confidence: 99%

Techno-Economic Assessment of Soiling Losses and Mitigation Strategies for Solar Power Generation

Ilse

Micheli

Figgis

et al. 2019

Joule

Self Cite

221

116

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Soiling consists of the deposition of contaminants onto photovoltaic (PV) modules or mirrors and tubes of concentrated solar power systems (CSPs). It often results in a drastic reduction of power generation, which potentially renders an installation economically unviable and therefore must be mitigated. On the other hand, the corresponding costs for cleaning can significantly increase the price of energy generated. In this work, the importance of soiling is assessed for the global PV and CSP key markets. Even in optimized cleaning scenarios, soiling reduces the current global solar power production by at least 3%-4%, with at least 3-5 billion V annual revenue losses, which could rise to 4%-7%, and more than 4-7 billion V losses, in 2023. Therefore, taking into account the underlying physics of natural soiling processes and the regional cleaning costs, a techno-economic assessment of current and proposed soiling mitigation strategies such as innovative coating materials is presented. Accordingly, the research and development needs and challenges in addressing soiling are discussed.

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Dew as a Detrimental Influencing Factor for Soiling of PV Modules

Cited by 70 publications

References 23 publications

Testing the Durability of Anti-Soiling Coatings for Solar Cover Glass by Outdoor Exposure in Denmark

Testing the Durability of Anti-Soiling Coatings for Solar Cover Glass by Outdoor Exposure in Denmark

Field test and electrode optimization of electrodynamic cleaning systems for solar panels

Techno-Economic Assessment of Soiling Losses and Mitigation Strategies for Solar Power Generation

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