Library Subscription: Guest
Proceedings of the 27th National and 5th International ISHMT-ASTFE Heat and Mass Transfer Conference December 14-17, 2023, IIT Patna, Patna-801106, Bihar, India
December, 14-17, 2023, Bihar, India

Solar Radiation Absorption and Thermo-Mechanical Analysis of Porous Absorbers

Get access (open in a dialog) DOI: 10.1615/IHMTC-2023.2060
pages 1261-1266


Recent focus on renewable energy resources and increased research in solar thermal applications have shown the potential application of porous absorbers in the receivers of concentrated solar plants. The numerical modelling of the solar energy conversion to thermal energy in these absorbers is complex and consists of coupling of various physics. The current work presents a coupled numerical model for thermo-mechanical analysis of a porous absorber. The spatial solar absorption distribution is obtained using a custom Monte Carlo Ray Tracing (MCRT) code. The radiation absorption of the receiver is analyzed based on absorption efficiency, followed by thermomechanical analysis. The pressure drop across the absorber, outlet temperature of heat transfer fluid and mechanical failure index are taken as the indicative of receiver performance. The effect of structural parameters like porosity and pore size on the radiation absorption and performance characteristics is investigated. The results indicate that the transmission losses dominate at high porosities and pore sizes and vice-versa for reflection losses. It is also observed that the effect of pore size on solar absorption characteristics is much less compared to porosity. The highest value absorption efficiency of 88.18 % is obtained at a porosity of 0.8 and pore size of 4 mm. Thermomechanical analysis reveals that higher porosities and pore sizes result in reduced failure indices and lower pressure drops. The lowest FI value of 0.353 is obtained at a porosity of 0.95 and a pore size of 3 mm. Thermal performance is compromised, leading to lower fluid outlet temperatures. The results of the present work are helpful in better design and mechanical failure prediction of VSRs.