Yazar "Khanlari, Ataollah" seçeneğine göre listele

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    Analysis of a spiral-formed solar air heating system with ceria nanoparticles-enhanced absorber coating
    (Elsevier Ltd, 2023) Khanlari, Ataollah; Badali, Yosef; Tuncer, Azim Doğuş
    Solar air heating systems are extensively applied in different applications in order to provide hot air using clean energy. In this study, a spiral type solar collector has been proposed, numerically simulated and manufactured. The main aim of this work is investigating the overall performance of a solar collector with spiral type absorber. In the first stage of this work, CFD approach has been used for simulating unbaffled and baffled spiral solar collector. Numerical findings exhibited better thermal performance of the baffled spiral collector. Therefore, in the following step of this survey, baffled spiral collector has been fabricated and experimentally analyzed at different conditions. In addition, ceria nanoparticles have been used in coating process of spiral-formed absorber plate of the system to upgrade the thermal efficiency. Mean thermal efficiency for spiral collector with and without nano-coating was obtained between 46.15 and 67.39%. Mean efficiency enhancement by using ceria nanoparticle coating in the tests made at 0.009 and 0.014 kg/s are 16.79% and 11.05%, respectively. Also, average exergy efficiency of spiral collector was achieved between 10.28 and 14.46%. Average sustainability index of spiral collector was gained in the range of 1.1151–1.1698. The overall findings of this study indicated successful utilization of the developed spiral type solar collector. Moreover, using ceria nanoparticle coating has significant positive effects on improving thermal efficiency of spiral collector. It can be concluded that the developed spiral type solar collector could be used in building integrated applications for providing fresh and heated air.
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    Application of carbon-based nanomaterials in solar-thermal systems: An updated review
    (Pergamon-Elsevier Science Ltd, 2024) Tuncer, Azim Doğuş; Badali, Yosef; Khanlari, Ataollah
    Increasing the world population makes it necessary to look for alternative and sustainable energy resources to meet the rising energy demand. In recent years, the utilization of different renewable energies has been accelerated because of the negative effects of fossil fuels and their limited resources. Among different solar energy technologies, solar liquid and air collectors are extensively utilized for providing heated water and air. Rapid development in science and technology makes it possible to improve the performance of solar collectors. Producing nanomaterials and using the obtained nano-sized particles for improving the thermophysical specifications of the working fluid or coating material can be considered for performance improvement. In the present study, applications of carbon-based nanomaterials (CBNMs) in various solar thermal systems have been reviewed comprehensively. In other words, the effects of utilizing carbon-based nanomaterials as promising material on the overall performance have been investigated. Preparation techniques and thermophysical specifications of carbon-based nanomaterials have been explained in detail. Also, utilization of carbon-based nanomaterials in seven widely utilized solar-thermal technologies and their impacts on the thermal behavior of the tested system have been concluded. This review gives a general perspective about applicability of carbon-based nanomaterials for performance enhancement in various solar-thermal systems.