One can note that in the special case of a small area A and surrounded completely by a high temperature heater Te, which are the conditions of ee=1, the net radiation power will now be approximately equal to (ea)sA(Te4-Ta4). Note that the radiative power follows a power law that is T4. (T is in Kelvin).
MHI heating elements and microheaters are designed for high emissivity.
Elements like the nanostructured GAXP™, No-Age ™ or MP1900™, Microheaters™ and Magnacoils™ . These are best free (open) radiating heating elements and materials.