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Radiative transfer is the dominant mode of heat transfer at high temperature for an absorbing-scattering media. Due to the complex solving of radiative transfer equation, radiative transfer is usually omitted in conventional heat transfer analysis of molten salt. In this study, the radiative, conductive and laminar convective coupled heat transfer of molten salts was numerically analyzed by the codes compiled based on finite element method (FEM) coupled with commercial Fluent software. The effects of radiative transfer on temperature distribution of molten salts were analyzed. Besides, the effects of scattering albedo, refractive index and fluid inlet velocity on temperature distribution of molten salts were also investigated. The numerical results indicated that the maximum elevated temperature deviation can reach up to 47.4% (101 K) when radiative transfer was not considered.

Solar driven CO 2 reforming of methane can store extra 20% concentrated solar energy to chemically bonded energy. With the aim to evaluate key operational parameters on energy storage efficiency, a finite volume method (FVM) coupled with thermochemical kinetics was developed to analyze the solar driven CO 2 methane reforming performance in a metallic foam thermochemical reactor. The LH kinetic model of CO 2 reforming of methane was compiled by user defined functions (UDFs) to exactly predict the temperature distribution and mole fractions of gas species. The numerical results were validated with experimental results which were tested in Niigata University to guarantee the accuracy of the developed model. Effects of gas mixture inlet velocity, porosity of metal foam reactor, CH 4 /CO 2 ratio and heat flux distribution on energy storage efficiency were analyzed for providing theoretical guideline to the application of solar driven CO 2 methane reforming. The numerical results indicated that maximum energy storage efficiency of CO 2 reforming of methane was found when the CH 4 /CO 2 ratio is 0.67.

To solve the dead space problem of conventional cavity receiver and increase energy conversion efficiency, cavity receiver with bottom surface interior convex was designed and fabricated. A low cost biaxial sun-tracking concentrated solar thermal utilization system using Fresnel lens as concentrator was designed and fabricated to test the thermal performance of cavity receiver, which can give a guidance for lab test of thermal performance of cavity receiver. Optical performance and thermal efficiency of cavity receiver with bottom surface interior convex was analyzed and measured through optical analysis and experimental test. Optical analysis indicated that the optical efficiency of the cavity receiver with bottom surface interior convex was 6.02% higher than that of conventional cavity receiver. A 4-h outdoor test showed that the average thermal efficiency of the cavity receiver with bottom surface interior convex was 4.1% higher than that of conventional cavity receiver.