An approximate method for calculating the heat flux through a solar collector honeycomb

An approximate calculation of the radiative-conductive flux of heat from the absorber to the cover plate of a flat plate collector equipped with a convection-suppressing honeycomb is developed, using an exponential kernel approximation to the passage transmittance function of the honeycomb cells. Fluxes predicted by this method are found to be in satisfactory agreement with the results of previously reported calculations and experiments. If a selective absorber plate is used in a collector of this type, heat transport by the air in the collector eliminates the radiation slip between the honeycomb and the absorber plate, so that thermal emission by the walls of the honeycomb in close proximity to the hot absorber may largely cancel out the advantage gained by making the absorber plate selective.