Improving the performance of large-aperture parabolic trough solar concentrator using semi-circular absorber tube with external fin and flat-plate radiation shield

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Journal Title
Journal ISSN
Volume Title
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
2020-10
Major/Subject
Mcode
Degree programme
Language
en
Pages
9
1215-1223
Series
Renewable Energy, Volume 159
Abstract
An improved absorber tube (AT) design consisting of a semi-circular and an external flat fin with a flat-plate radiation shield inside an evacuated annulus is proposed for large aperture parabolic trough concentrator (PTC) systems. In the present design, the AT's semi-circular part absorbs the most sun rays. The other rays originally absorbed by the AT's upper part is intercepted by the external two fins. The flat-plate radiation shield reflects the external radiation energy from the AT's upper half back to the AT. The trough has an aperture of 8m and an 80° half rim angle. The AT consists of a semicircle with a diameter of 100 mm and outer fins. The optical and thermal efficiency of this new design was up to 83.3% and 80.3%, respectively. The optical and thermal efficiency was 8%-units higher than that of the traditional optimal design. The maximum temperature always appears at the edge of the fin, which is up to 50 °C higher than that of the heat transfer fluid (HTF) at 0.5 m/s, which was the optimal fluid rate for the new design. The fins also contribute to the efficiency of the PTC: 6.5% to the optical and over 3.5% to the thermal efficiency. The improved AT design will help to plan more effective PTC systems.
Description
Keywords
Flat-plate radiation shield, Large aperture parabolic trough concentrator, Optical efficiency, Semi-circular absorber tube with fin, Thermal efficiency
Other note
Citation
Gong, J H, Wang, J, Lund, P D, Zhao, D D, Hu, E Y & Jin, W 2020, ' Improving the performance of large-aperture parabolic trough solar concentrator using semi-circular absorber tube with external fin and flat-plate radiation shield ', Renewable Energy, vol. 159, pp. 1215-1223 . https://doi.org/10.1016/j.renene.2020.06.059