Heat-technical investigation of newly developed aerogels and their vacuumized-graphite doped forms

The study examines the thermal properties of aerogels and their vacuumized and graphite-doped vacuumized forms. The thermal conductivity of vacuum insulation panels with different silica-based core materials, with and without carbon flakes, was investigated. Three varieties of fibrous aerogel were utilised as cores, and a separate silica-based microporous insulator served as a filler. The core materials were photographed, and the thermal conductivities of all materials were measured at different mean temperatures. The results on the applicability of these materials as filling cores for vacuum insulation panels are interesting. The results show that after vacuumizing the materials, a 3–20% reduction in thermal conductivity can be achieved, depending on the core material type. For the slentex, the graphite addition resulted in an additional 1.5%, while for the spaceloft, a further 4% decrease in thermal conductivity was observed compared to the vacuumized samples. For all percentage reductions in the calculations, we compared the measured vacuumised thermal conductivities to the initial pure non-vacuumised thermal conductivities. For pyrogel and microtherm, the addition of graphite did not reduce thermal conductivity. Our results show that vacuumization is always beneficial in reducing thermal conductivity, whereas graphite addition is beneficial but depends on the material's structure.