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Analyzing thermal properties of solar evacuated tube arrays coupled with mini-compound parabolic concentrator.
- Source :
-
Renewable Energy: An International Journal . Jun2020, Vol. 153, p155-167. 13p. - Publication Year :
- 2020
-
Abstract
- Effective utilization of solar energy resource enables to improve the thermal performance of solar evacuated tube. In present work, the back side of solar vacuum tube was coupled with mini-compound parabolic concentrator (mini-CPC). The thermal characteristics of the presented mini-CPC solar vacuum tube were analyzed theoretically and experimentally. A mathematical model of heat transfer for the mini-CPC vacuum tube was established according to the energy conservation, and solved by iterative calculation based on home-built C programming language. The obtained numerical solutions fit in well with the experimental results. Furthermore, analysis indicates the vacuum interlayer plays a crucial role in hindering heat transfer. The thermal-convection resistance (R co-air,conv) dominates the heat loss from cover tube to ambient rather than thermal-radiation resistance (R co-sky,rad). The measured final temperature increment of working water for the mini-CPC and ordinary evacuated tube can reach 63.4 K and 49.8 K, respectively. An experimental result also reveals that the thermal efficiency of the mini-CPC vacuum tube is increased by 24.3%–29.2% compared with that of vacuum tube without mini-CPC, considering various weather conditions. Consequently, the designed mini-CPC evacuated tube shows a preferable performance, which may provide a certain reference in technology for engineering applications. • A mini-CPC evacuated tube to utilize effectively solar energy was designed. • Construction and solution of heat transfer model for mini-CPC evacuated tube. • Theoretical solution fits in well with the experimental result. • The temperature increment of working water can reach 63.4 K for the mini-CPC. • The improved ratio of thermal efficiency is 24.3%–29.2%. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09601481
- Volume :
- 153
- Database :
- Academic Search Index
- Journal :
- Renewable Energy: An International Journal
- Publication Type :
- Academic Journal
- Accession number :
- 142537737
- Full Text :
- https://doi.org/10.1016/j.renene.2020.02.011