Numerical analysis of heat transfer in a passive solar composite wall with porous absorber

In this paper, heat transfer and flow in the two types of composite solar wall with porous absorber has been studied. The ‘unsteady’ numerical simulation is employed to analyze the performance of the flow and temperature field in the composite solar wall. The excess heat is stored within the porous absorber during solar radiation and there is stratification in the porous layer. So, the porous absorber works as thermal insulator in a degree when no solar shining is available. The heating characteristic of the two types of the composite solar wall with porous absorber has been analyzed. The influence of the particle size, the porosity, the thermal conductivity of porous layer and the porous absorber position in the solar composite wall on the air temperature in the heated room is significant. The results show that all these factors should be taken into account for a better design of the heating system.