THERMAL SCIENCE

International Scientific Journal

Hua Wang

,

Xuyang Li

,

Shukuan Xie

,

Lin Zhang

NUMERICAL STUDY OF FIN EFFECTS ON THERMAL PERFORMANCE OF ANNULAR SOLAR SALT-LAYERED VACUUM COLLECTOR TUBES

ABSTRACT
Previous research showed that integrating phase change materials with solar tubes stabilizes heat transfer fluid temperature, but the low conductivity of phase change materials limits solar tube performance. Although studies on fluid properties and heat transfer behavior are extensive, the critical influences of fin shapes' effect are limited. This paper introduces an innovative design: an all-glass vacuum tube with a solar salt sleeve surrounded by outer fins. Numerical simulations compare heat transfer dynamics of straight rectangular, circular, and trapezoidal fins. The study examines how these shapes affect temperature field evolution and phase transition. Results indicate: 1) Fins reduce temperature disparity between solar salt and heat transfer fluid, with rectangular fins showing the greatest improvement of only 12oC. 2) Fins accelerate salt phase transition, albeit with a slight delay in initiation. Adding trapezoidal ring fins reduces the complete phase change duration by 5 minutes. 3) the tube with 4 rectangular fins demonstrates the highest temperature field and maximum total heat storage of 269kJ, highlighting its superiority.
KEYWORDS
solar vacuum collector tube, phase change materials, fins, thermal characteristics
PAPER SUBMITTED: 2025-02-17
PAPER REVISED: 2025-03-25
PAPER ACCEPTED: 2025-04-22
PUBLISHED ONLINE: 2025-07-05
DOI REFERENCE: https://doi.org/10.2298/TSCI250217114W
CITATION EXPORT: view in browser or download as text file
THERMAL SCIENCE YEAR 2025, VOLUME 29, ISSUE No. 6, PAGES [4879 - 4890]
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Numerical study of fin effects on thermal performance of annular solar salt-layered vacuum collector tubes

© 2026 Society of Thermal Engineers of Serbia. Published by the Vinča Institute of Nuclear Sciences, National Institute of the Republic of Serbia, Belgrade, Serbia. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International licence