Photothermal convection of a magnetic nanofluid in a direct absorption solar collector
Nanofluid-based direct absorption of solar heat results in thermal efficiencies superior to conventional solar thermal technology. In addition, convection of nanofluid can be sustained pump-free in the collector. In this article, we study an aqueous magnetic nanofluid capable to establish the photot...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier Ltd
2022
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| Subjects: | |
| Online Access: | View Fulltext in Publisher |
| Summary: | Nanofluid-based direct absorption of solar heat results in thermal efficiencies superior to conventional solar thermal technology. In addition, convection of nanofluid can be sustained pump-free in the collector. In this article, we study an aqueous magnetic nanofluid capable to establish the photothermal convection in a lab-scale direct absorption solar collector equipped with a solenoid. The nanofluid consisted of 60-nm Fe2O3 particles dispersed in distilled water at concentration in the range 0.5% wt.-2.0% wt. An empirical model of the photothermal convection was developed based on the experiments. The model accounted for magnetic and thermophoretic forces acting within the nanofluid. The nanofluid with up to 2.0% wt. iron oxide nanoparticles obtained the velocity of ∼5 mm/s under the magnetic field of up to 28 mT. This resulted in the maximum thermal efficiency of the collector equal to 65%. © 2022 The Author(s) |
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| ISBN: | 0038092X (ISSN) |
| DOI: | 10.1016/j.solener.2022.04.027 |