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Soiling effect in second-surface CSP mirror and improved cleaning strategies

Deployment of future Concentrated Solar Power, CSP, plants is foreseen to take place in many locations worldwide, namely on Alentejo, Portugal, a region with great potential for solar energy harvesting. For the operation and maintenance of such power plants, it is important to know in advance the potential influence that soiling can have in second-surface mirrors, so called because the silver is deposited on the rear face of the mirror, particularly in their specular reflectance.

For this reason, a study* regarding the effects of soiling in second-surface mirrors’ specular reflection is carried out during a period of one year and a half. Moreover, and since soiling particle deposition can have a crucial economic impact for the energy management of CSP plants, it is important to analyze and establish a method to improve the cleaning operations of a CSP plant considering local conditions. The applied methodology is based in programming artificial cleaning profiles based on ground soiling effect and direct normal irradiance measurements, which are then introduced in a plant simulator to estimate the yearly annual energy production. The generated energy is then used to compare different profiles in face of any possible energy selling price and cleaning costs. The presented method is unique in comparison with current literature, due to its versatility, and can be used for any region.

(*) R. Conceição, F. M. Lopes, A. Tavares, and D. Lopes, “Soiling effect in second-surface CSP mirror and improved cleaning strategies,” Renew. Energy, vol. 158, pp. 103–113, 2020, doi: 10.1016/j.renene.2020.05.054.

More information: Ricardo Conceição, Postdoctoral researcher, High Temperature Processes Unit, ricardo.conceicao@imdea.org

Normalized profitability (regarding the clean state of the plant) as function of the mirrors cleaning price for different cleaning profiles, such as 1W, which stands for cleaning every week, and 5M, which stands for cleaning every 5 months.

 

Event Date: 
Monday, July 13, 2020