HEAT TRANSFER IN A SOLAR CAVITY RECEIVER: DESIGN CONSIDERATIONS

The thermal performance of a cylindrical solar cavity with a convective boundary is modeled using Monte Carlo ray tracing to evaluate the impact of the geometry and the spectral characteristics of the surface on the absorption efficiency and the spatial distribution of temperature. Increasing cavity size for a fixed aperture size increases absorption efficiency and reduces wall temperature. Inconel, which serves effectively as a selective surface, provides the highest absorption efficiencies at over 90%. A surface coating of aluminum oxide produces a more uniform and lower average temperature distribution.