Spectral selective radiating materials for direct radiative heating

Conventional infrared radiants for heating emit IR radiation spectrally broadly and make energy loss because of the absorption by the atmosphere. This loss is not negligible in a large space. Using a spectral selective radiant which emits the IR radiation only between 8 and 13 μm in wavelength, we can heat the objectives directly decreasing the energy loss due to the atmospheric absorption. As an example, an SiO film on an Al film was deposited on a glass substrate. Spectral emittance in IR region was measured using an FT-IR. To confirm the direct heating properties, we calculated radiance reaching arbitrary distance from the radiant. As a result, the IR radiation emitted from the radiant at a distance of 10 m was about 10% greater than that from the blackbody, depending on the atmospheric condition.