Thermal rectification in a bilayer wall: Coupled radiation and conduction heat transfer

Highlights: • Coupled conduction and radiation bilayer walls can be used as thermal diodes. • Rosseland and thin media approximations lead to equal maximum rectification factors. • Rectification factor of 2.62 is theoretically possible. - Abstract: Like electronic diode developed for the control of electric current, it may be desirable to build thermal diodes that control heat transfer. This thermal rectification effect can occur when heat is transferred asymmetrically. We consider in this work, the case of a composite wall, one layer of which is both conductive and radiative. Both Rosseland and surface radiation approximations are used for taking into account radiative transfer. Analytical expressions for the rectification factor are given. It is shown that this factor is bounded by a maximum value of around 2.62.