Enhanced heat transfer in a parabolic trough solar receiver by inserting rods and using molten salt as heat transfer fluid

Research output: Contribution to journalArticle

Authors

  • Chun Chang
  • Zhiyong Wu
  • Xin Li
  • Mingzhi Zhao
  • Jie Deng
  • Zhifeng Wang

Colleges, School and Institutes

External organisations

  • Institute of Electrical Engineering, Chinese Academy of Sciences
  • Inner Mongolia University of Technology

Abstract

With the aim to enhance the reliability and overall heat transfer performance of a parabolic trough receiver, concentric rod and eccentric rod are introduced as turbulators, and the flow and convective heat transfer characteristics of molten salt in a parabolic trough receiver are analyzed. A three-dimensional model was developed and has been validated with experimental results and empirical equations. Highly non-uniform heat flux was provided by a novel parabolic trough collector. The result shows that both concentric rod insert and eccentric rod insert can enhance the heat transfer performance effectively. For a parabolic trough receiver with a concentric rod insert, with the increasing of dimensionless diameter B, the normalized Nusselt number is about 1.10 to 7.42 times over a plain parabolic trough receiver. The performance evaluation criteria can't reasonably evaluate the effect of B growth on the comprehensive heat transfer performance. By introducing integrated performance factor, it can give a reasonable solution, and it shows that the integrated performance factor has a significance decreases with the increase of Reynolds number when B is larger than 0.8. With B increasing, the integrated performance factor of parabolic trough receiver with concentric rod insert decreasing under a certain Reynolds number. For an eccentric rod insert, the performance evaluation criteria and the integrated performance factor decrease with the increasing of Reynolds number under a certain dimensionless eccentricity H. The performance evaluation criteria decreases from about 1.84 to 1.68 times over a plain parabolic trough receiver when H is 0.8. Moreover, the temperature distribution can be uniformed and the maximum temperature on the absorber tube also can be remarkably reduced with the increasing of B and H under a certain Reynolds number, which helps to reduce the thermal deflection and increase the reliability for a parabolic trough receiver.

Details

Original languageEnglish
Pages (from-to)337-350
Number of pages14
JournalApplied Energy
Volume220
Early online date30 Mar 2018
Publication statusPublished - 15 Jun 2018

Keywords

  • Concentric rod and eccentric rod inserts, Integrated performance factor, Molten salt, Non-uniform heat flux, Parabolic trough receiver, Performance evaluation criteria