, Kamel ZOUGGAR -
, Khelifa GUERRAICHE -
, Antar TAHIRI -
, Zied DRISS -
, Cherif BOUGRIOU -
, Aya YAHA -
2Department of Mechanical Engineering, Faculty of Technology, Structures and Solid Mechanical Laboratory (LMSS), , Djillali Liabes University of Sidi Bel Abbes, Sidi Bel Abbes, 22000, Algeria
3Department of Mechanical Engineering, Faculty of Technology, University of Batna 2, Batna, 05000, Algeria
4Faculty of Science and Technology, Ziane Achour University of Djelfa, Djelfa,17001, Algeria
5National Department of Engineers of Sfax (ENIS), Laboratory of Electromechanical Systems (LASEM), University of Sfax, 3029, Tunisia
6Department of Physics, Faculty of Matter Sciences, University of Batna 1, 05000, Algeria
Abstract
Parabolic trough solar concentrators (PTCs) encounter significant challenges arising from Non-Uniform Heat Flux (NUHF) around the receiver, which causes local overheating and pronounced circumferential temperature gradients. This study proposes the solution to this problem by uniforming the heat flux distribution, minimizing the temperature gradient, and improving performance. A numerical analysis is carried out on a novel small-scale PTC model featuring a concentric absorber tube design. The study compares the heat recovery performance of conventional, concentric, and eccentric absorber configurations using two heat transfer fluids enhanced with nanofluids: water and Syltherm-800 oil. A three-dimensional simulation model was presented by coupling Monte Carlo Ray-Tracing (MCRT) with (CFD) in ANSYS Fluent to predict the thermo-hydraulic response of parabolic trough receivers. Furthermore, Particular attention is given to the effects of Particular attention is given to the effects of critical operational factors, namely inlet fluid temperature, mass flow rate, and nanofluid concentration on heat transfer and overall efficiency. The results confirm that the concentric parabolic trough receiver (PTR) operates with lower peak wall temperatures and smaller circumferential thermal gradients, which lessen thermal stresses and supports higher overall efficiency. When compared to the reference design, the concentric and eccentric receiver tube configurations lower the absorber tube’s temperature gradient by roughly 45% and 60.6%, respectively. These new configuration enhance heat collecting efficiency by up to 2.62% and 3.26% relative to the smoothe PTC tube. Moreover, the use of nanofluids added significant enhancements of efficiency, by 6.12% and 8.23% for the concentric and eccentric arrangements, respectively. This work highlights the promise of novel receiver designs and the use of nanofluids to boost both thermal and mechanics performance of PTCs and contributes knowledge beyond earlier work in the literature and serves toward improving solar thermal.
