Optical properties, durability, and system aspects of a new aluminium-polymer-laminated steel reflector for solar concentrators

Brogren, Maria; Helgesson, Anna; Karlsson, Björn; Nilsson, Johan; Roos, Arne

doi:10.1016/j.solmat.2004.01.029

Cited by 66 publications

(34 citation statements)

References 20 publications

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“…In addition, improvements could also be achieved by modifying the manufacturing process. Nowadays, reflecting metals are chemically deposited in the back of extra clear glass in such a way that reflecting metals are atmosphere protected (second face mirror configuration), but partially scarifying the specular reflectance [10]. In first face mirrors, the reflecting material is deposited directly on top of the glass.…”

Section: Introductionmentioning

confidence: 99%

On the Effect of Thin Film Growth Mechanisms on the Specular Reflectance of Aluminium Thin Films Deposited via Filtered Cathodic Vacuum Arc

et al. 2018

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The optimisation of the specular reflectance of solar collectors is a key parameter to increase the global yield of concentrated solar power (CSP) plants. In this work, the influence of filtered cathodic vacuum arc deposition parameters, particularly working pressure and deposition time, on the specular and diffuse reflectance of aluminium thin films, was studied. Changes in specular reflectance, measured by ultraviolet–visible and near-infrared spectroscopy (UV-vis-NIR) spectrophotometry, were directly correlated with thin film elemental concentration depth profiles, obtained by Rutherford backscattering spectrometry (RBS), and surface and cross-sectional morphologies as measured by scanning electron microscopy (SEM) and profilometry. Finally, atomic force microscopy (AFM) provided information on the roughness and growth mechanism of the films. The two contributions to the total reflectance of the films, namely diffuse and specular reflectance, were found to be deeply influenced by deposition conditions. It was proven that working pressure and deposition time directly determine the predominant factor. Specular reflectance varied from 12 to 99.8% of the total reflectance for films grown at the same working pressure of 0.1 Pa and with different deposition times. This transformation could not be attributed to an oxidation of the films as stated by RBS, but was correlated with a progressive modification of the roughness, surface, and bulk morphology of the samples over the deposition time. Hence, the evolution in the final optical properties of the films is driven by different growth mechanisms and the resulting microstructures. In addition to the originally addressed CSP applications the potential of the developed aluminium films for other application rather than CSP, such as, for example, reference material for spectroscopic diffuse reflectance measurements, is also discussed.

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Section: Introductionmentioning

confidence: 99%

On the Effect of Thin Film Growth Mechanisms on the Specular Reflectance of Aluminium Thin Films Deposited via Filtered Cathodic Vacuum Arc

et al. 2018

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“…Mirrors can be classified into three main types: glass, aluminum, and polymer mirrors. 8,9 Several plants have been installed and exploited since 1980 10,11 using glass monolithic mirrors, and little degradation of the mirrors has been observed. However, mirror technologies have since evolved, and new mirrors on the market differ from the ones installed on these plants.…”

Section: Introductionmentioning

confidence: 99%

Accelerated aging test modeling applied to solar mirrors

et al. 2019

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The durability of solar mirrors is a critical factor for the deployment of concentrating solar power plants. Accelerated aging test models currently applied in the polymer, electronic, and photovoltaic fields have recently been reviewed, and the issues of their application to solar mirrors have been discussed. This article first reports the results of temperature, humidity, and light irradiance accelerated aging tests performed to assess the dependent parameters of selected models from the literature. These parameters include the apparent activation energy for the Arrhenius temperature law, the Peck and Eyring coefficients for humidity models and the Schwarzschild coefficient for the irradiance law. The experimental values were then assessed for specular reflectance loss of solar mirrors. Finally, using these parameters, acceleration factors were calculated for solar mirrors. An effective temperature considering the Arrhenius degradation law was used rather than the commonly used mean temperature. This question is also addressed for light irradiance by using the dose instead of the mean value.

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“…Utilisation of solar energy is central to most of these efforts. Although photovoltaic conversion has technologically matured rapidly, 'Concentrating Solar Power aluminium [17] with an additional protective polymer coating. Comparative optical tests [18] were carried out and reported earlier on these materials, mainly to correlate the efficiency as a function of exposure/ service time in a solar concentrator [19].…”

Section: Introductionmentioning

confidence: 99%

Electrodeposition of δ-phase based Cu–Sn mirror alloy from sulfate-aqueous electrolyte for solar reflector application

Alex

Basu

Sengupta

et al. 2016

Applied Thermal Engineering

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Copper-tin (Cu-Sn) intermetallic alloy coating was developed on mild steel substrate by galvanostatic electrodeposition technique from sulfate-based acidic electrolyte containing Laprol as additive. The homogenous coating containing cubic  phase with composition of 32.6 % Sn was obtained, when a current of -8.5 mA was made to flow through the electrochemical bath. The optimized coating with thickness of ~ 0.4 -3 µm exhibits ~ 80% specular reflectance. The coating has a hardness of 2.6 GPa, suggesting a good scratch resistance property. The experimental results also suggest that the hydrophobic surface of Cu-32.6% Sn thin film can be potentially used as an attractive coating for solar reflector application under dusty and humid conditions. 1. (CSP) technology', still represents one of the most promising and affordable solar technologies where, sunlight is converted into higher or lower grade thermal energy [1]. An increasing number of CSP plants have been constructed in the last decades [2] towards fulfilling our growing energy demand and a further growth for this renewable technology is envisaged in coming future. Briefly, CSP [3] technology utilizes parabolic troughs, solar towers, and parabolic dishes to concentrate the solar energy using reflective surfaces. Concentrating collectors requires large reflectors [ 4 ] to ´concentrate´ the incident solar radiation onto a smaller receiver. An assembly of mirrors [5,6] is required to reflect and to focus the sunlight onto a receiver containing a heat transfer fluid (HTF), such as molten salt, steam, oil, compressed air [7] etc. The hot fluid is then utilized to produce electric power through standard steam turbines [8]. Reflectors are an essential part of CSP systems and considerable amount of research has been devoted in the development and improvement of reflector materials. [ 9 , 10 ] Reflectors in CSP systems [11] require a high reflectance over the entire solar spectrum, durability to outdoor exposure and resistant to all forms of degradation over time, particularly from humid conditions and dust in order to improve their lifetime in adverse environment of the solar fields [12]. Most of the large-scale CSP systems, installed till now, utilize glass reflectors [13]. Although these mirrors have maintained their reflectance very well in severe environments, they are prone to wind-related breakage and are expensive to transport and install. In order to overcome this issue, immediate attention is required for alternative lowercost reflectors to reduce the cost of CSP systems. From a variety of different material constructions, the mirror materials showing promise for long-term outdoor applications, [14] are reported to be made up of various silvered glass mirrors [ 15 ], a silvered polymeric mirror [ 16 ], and an anodized sheet

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Optical properties, durability, and system aspects of a new aluminium-polymer-laminated steel reflector for solar concentrators

Cited by 66 publications

References 20 publications

On the Effect of Thin Film Growth Mechanisms on the Specular Reflectance of Aluminium Thin Films Deposited via Filtered Cathodic Vacuum Arc

On the Effect of Thin Film Growth Mechanisms on the Specular Reflectance of Aluminium Thin Films Deposited via Filtered Cathodic Vacuum Arc

Accelerated aging test modeling applied to solar mirrors

Electrodeposition of δ-phase based Cu–Sn mirror alloy from sulfate-aqueous electrolyte for solar reflector application

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