CONDUCTION AND CONVECTION HEAT-TRANSFER IN COMPOSITE SOLAR COLLECTOR SYSTEMS WITH POROUS ABSORBER

Steady natural convection and conduction heat transfer has been studie d in composite solar collector systems. The system consists of a glazi ng, a porous layer and a massive wall installed in a room. The heat tr ansfer in this system is studied by assuming the glazing and the verti cal bounding wall isothermal at different temperatures, two horizontal bounding walls adiabatic and porous layer without vents. The aspect r atio A was from 0.1 to 1.0 but the detailed study was carried out with A=1. The thickness of the porous wall F(p) varied from 1/3 to 1, whil e the solid wall thickness was kept constant. The conductivity ratio o f porous layer was from 10(-2) to 10(2), Ra from 10(3) to 10(7). The r esults are presented in terms of thermal parameters as function of Ra and non-dimensional geometrical parameters. The isotherms and stream l ines within the system are produced.