Transparent thermal insulation with infrared-absorbing gases

Abstract We investigate the radiative heat transfer between blackbody-like surfaces confining an infrared-absorbing gas layer. Spectrophotometric measurements on selected gases lead us to optimized compositions with sulfur hexafluoride, propyne, and different freons. Theoretically, the gas is able to diminish the radiative heat flux across a 1 cm thick slab by a factor of ∼ 0.7 in comparison with the case of a nonabsorbing medium. Infrared-absorbing gases seem to offer interesting possibilities for improved transparent thermal insulation of windows.