Significant photothermal conversion enhancement of nanofluids induced by Rayleigh-Bénard convection for direct absorption solar collectors

Kongxiang Wang, Yan He, Ankang Kan, Wei Yu, Debing Wang, Liyie Zhang, Guihua Zhu, Huaqing Xie and Xiaohui She

Applied Energy, 2019, vol. 254, issue C

Abstract: Large temperature gradients and serious nanoparticles aggregation are the two vital issues, which lead to a low photothermal conversion efficiency of Nanofluids-Based Direct Absorption Solar Collectors (NB-DASCs) in the solar thermal utilization. It is reported that reverse illumination is a good way to address the above issues of the NB-DASCs, which can change the way of energy transport by Rayleigh-Bénard convection. However, the previous studies are based on simulation and few experiments are found. In this paper, a novel test rig is designed for the first time to experimentally study the reverse illumination NB-DASCs. Uniform temperature distribution inside nanofluids is obtained. It is found that the photothermal conversion efficiency of the reverse illumination NB-DASCs is up to 51.9% in a continuous test of 10,000 s, which is 99.6% higher than that of the conventional NB-DASCs. Furthermore, the spontaneous convection, resulted from reverse illumination, can effectively alleviate the sedimentation and agglomeration of nanoparticles, which enhances the stability of nanofluids. In addition, the mechanism is also studied in detail. This paper provides a practical avenue for improving the solar thermal conversion efficiency of the direct absorption solar collectors.

Keywords: Nanofluids; Photothermal conversion; Direct absorption solar collectors; Solar energy (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (10)

Downloads: (external link)
http://www.sciencedirect.com/science/article/pii/S0306261919313935
Full text for ScienceDirect subscribers only

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:eee:appene:v:254:y:2019:i:c:s0306261919313935

Ordering information: This journal article can be ordered from
http://www.elsevier.com/wps/find/journaldescription.cws_home/405891/bibliographic
http://www.elsevier. ... 405891/bibliographic

DOI: 10.1016/j.apenergy.2019.113706

Access Statistics for this article

Applied Energy is currently edited by J. Yan

More articles in Applied Energy from Elsevier
Bibliographic data for series maintained by Catherine Liu ().