I've been also looking at ceramic microspheres as a possible additive to refractory to enhance the performance of those areas which are exposed to high temperatures. The batch box
rocket stove is supposed to have an insulated firebox, I believe. It would be interesting to investigate the impact of ceramic microspheres as a cement additive painted on layer to the fire exposed surfaces. Eagle coatings is a Canadian company using the microspheres to solve heating and cooling problems. There are others. For example, the Denver airport allegedly had a 30 % odd
energy bill reduction resulting from the application of paint containing insulating ceramic microspheres. This technology seems to be largely flying under the radar at the moment. One problem is that it requires a different analysis in order to understand how the technology works. R value doesn't appear to be relevant to the analysis of this technology.
Has anyone tried to use the ceramic microspheres in their favorite heating appliance?