Heat transfer simulation of a solar test stand

A transient heat transfer model for a solar test stand is presented here to predict temperatures of the absorber plates on a solar test stand, instead of consuming excessive time to conduct numerous experiments. Three zones are defined in this model for the test stand: glass, enclosed-air, plates/insulation layers. A radiation model for the glass layer is developed here to achieve more accurate simulation. This model combines a cold medium without scattering approximation for solar irradiation together with optically thick approximation for infrared thermal radiation, thereby simplifying the spectral dependence on the semitransparent medium of glass. The numerical simulation to obtain three-dimensional transient temperature predictions is made with the finite-volume discretization and alternating directional implicit (ADI) scheme together with the Crank-Nicolson approach. In addition, the coupling effects on the interfacial boundary are handled by the iterative method. The model is validated by comparing the measured temperatures with the predicted ones at selected positions. It is found that the deviations between measured and predicted temperatures on the absorbing plates fall within 3 K (about 1%), which validates the computational model developed in this study.