Heat transfer enhancement of a molten salt parabolic trough solar receiver with concentric and eccentric pipe inserts

In this work, numerical investigations have been performed on the enhanced flow and heat transfer in a parabolic trough receiver (PTR) with molten salt as heat transfer fluid(HTF). A three-dimensional simulation model is established, and the non-uniform heat flux and detailed temperature distribution of a PTR is successfully simulated by combining a MCRT code and FLUENT software. Concentric and eccentric pipe inserts were used to enhance heat transfer potential in the absorber tube of PTR, and the effects of key parameters of the inserts were investigated by comparison. The thermo-hydraulic performance has been evaluated. The results show that the inserts can significantly improve the comprehensive heat transfer performance of more than 1.64 times than a PTR without inserts when the PTR is inserted by A3. And the eccentric pipe inserts of B3 performs significantly better than the concentric tube inserts for its excellent performance in decreasing the maximum temperature of absorber tube and molten salt. The results of this study are helpful in the optimization design of a PTR with molten salt HTF technology.