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With the aim to increase the overall heat transfer performance and reliability of tube receiver for parabolic trough solar collector system, asymmetric outward convex corrugated tube is introduced as the metal tube of parabolic trough receiver. An optical-thermal-structural sequential coupled method was developed to study the heat transfer performance and thermal strain of tube receiver for parabolic trough solar collector system. Heat transfer performance and thermal strain comparisons between conventional tube receiver and asymmetric outward convex corrugated tube receiver are conducted. The researches indicated that the usage of asymmetric outward convex corrugated tube as receiver can enhance the heat transfer performance and reduce the thermal strain effectively. By using asymmetric outward convex corrugated tube as receiver, the maximum enhancement of overall heat transfer performance factor is 148% and the maximum restrain of von-Mises thermal strain is 26.8%.

Increasing CO2 emission problems create urgent challenges for alleviating global warming, and the capture of CO2 has become an essential field of scientific research. In this study, a finite volume method (FVM) coupled with thermochemical kinetics was developed to analyze the solar driven CO2 methane reforming process in a metallic foam reactor. The local thermal non-equilibrium (LTNE) model coupled with radiative heat transfer was developed to provide more temperature information. A joint inversion method based on chemical process software and the FVM coupled with thermochemical kinetics was developed to obtain the thermochemical reaction parameters and guarantee the calculation accuracy. The detailed thermal and thermochemical performance in the metal foam reactor was analyzed. In addition, the effects of heat flux distribution and porosity on the solar driven CO2 methane reforming process were analyzed. The numerical results can serve as theoretical guidance for the solar driven CO2 methane reforming application.

Nanofluid-based spectral splitting concentrating photovoltaic thermal (CPV/T) system enables photovoltaic (CPV) cells and thermal absorbers to operate at different temperatures and realizes the utilization of full-spectrum sunlight. It is important to find one kind of low cost nanofluid that can be applied to nanofluid-based spectral splitting CPV/T system. In this study, the feasibility of using cost-effective glycol-ZnO nanofluid in spectral splitting CPV/T system was experimentally verified. A two-axis sun-tracking nanofluid-based spectral splitting CPV/T system was designed and fabricated. The solar energy conversion efficiency correlation coefficient was utilized to compare the thermodynamic performance of glycol-ZnO nanofluid-based spectral splitting CPV/T system with those of water-polypyrrole and water-Ag-SiO2 nanofluid-based spectral splitting CPV/T system. The effects of ZnO nanoparticles concentration in glycol-ZnO nanofluid on thermal and electrical performances were investigated. The cost comparisons of different types of nanoparticles were also conducted. The results indicated that the correlation coefficient of glycol-ZnO nanofluid-based spectral splitting CPV/T system was 0.218 and 0.05 higher than those of water-polypyrrole and water-Ag-SiO2 nanofluid-based spectral splitting CPV/T system, respectively. The cost of ZnO nanoparticles was 0.13%, 0.08% and 0.17% of cost of Au, Ag and polypyrrole nanoparticles, respectively.