Not only is the energy efficiency of buildings nowadays becoming more and more important; the legislative requirements, the people’s awareness of the environmental questions and their thermal com- fort expectations are also on a much higher level. all of these issues can be addressed by making the building envelope more thermally resistant. however, with the traditional thermal insulation materials the thickness of thermal insulation layers is already at the viable limits. Therefore, the development of new, more efficient thermal insulation products with a higher thermal resistance is highly promoted. Preliminary research results can be applied to models to develop and confirm the conceptual designs of such new materials. In this paper, an analysis of thermal performance is presented for a novel thermal insulation consisting of graphite polystyrene (gPS) matrix with cavities filled with an insulative gas, and a protective sheath to prevent it from leaking. bearing in mind the suitability for later production, differ- ent configurations of the assembly were considered, regarding the matrix geometry, the type of the gas filling, and the surface emissivity of the cavities. a range of numerical simulations of heat transfer was conducted to determine the efficiency of different designs in reducing the conductive, the convective, and the radiative heat transfer. advantages, limitations and some detailed parameters of the proposed design concepts were determined, which were then used for optimisation. The analysis of the results indicates that the equivalent thermal conductance of a gPS panel can be significantly reduced by the introduction of gas-filled cavities. The reduction is highly dependent on the type of the gas filling (ther- mal conductivity, viscosity, specific heat, etc.), the size of the cavities, and the cavity surface emissivity.
gas-filled cavities, graphite polystyrene, numerical simulation, thermal insulation
 Berge, A. & Johansson, P., Literature Review of High Performance Thermal Insulation,
Chalmers University of Technology: Gothenburg, Sweden, 2012.
 Baetens, R., Jelle, B.P., Thue, J.V., Tenpierik, M.J., Grynning, S., Uvsløkk, S. & Gustavsen, A., Vacuum insulation panels for building applications: A review and beyond. Energy and Buildings, 42(2), pp. 147–172, 2010. https://doi.org/10.1016/j.enbuild.2009.09.005
 Baetens, R., Jelle, B.P. & Gustavsen, A., Aerogel insulation for building applications:
A state-of-the-art review. Energy and Buildings, 43(4), pp. 761–769, 2011. https://doi.org/10.1016/j.enbuild.2010.12.012
 Griffith, B.T., Arasteh, D. & Türler, D., Gas-filled panels: An update on applications in the building thermal envelope. Superinsulations and the Building Envelope, Proceedings of the BETEC Fall Symposium, pp. 1–13, 1995.
 Baetens, R., Jelle, B.P., Gustavsen, A. & Grynning, S., Gas-filled panels for building applications: A state-of-the-art review. Energy and Buildings, 42(11), pp. 1969–1975,
 Japelj Fir, M., Kralj, A., Žnidaršič, M. & Remec, Č., S plinom polnjeni paneli za visokoizolacijske stavbne ovoje 21, stoletja. Gradbeni Vestnik, 61, pp. 159–167, 2012.
 Fi-Foil Company, www.gfpinsulation.com
 Coldpack, www.coldpack.com
 SIST EN ISO 10211:2017. Thermal bridges in building construction – Heat flows and surface temperatures – Detailed calculations. https://doi.org/10.3403/30143206u
 SIST EN ISO 10077-2:2017. Thermal performance of windows, doors and shutters – Calculation of thermal transmittance – Part 2: Numerical method for frames. https://doi.org/10.3403/30323247
 SIST EN 673:2011. Glass in building – Determination of thermal transmittance (U value) – Calculation method. https://doi.org/10.3403/02351907u
 Incropera, F.P. & DeWitt, D.P., Fundamentals of Heat and Mass Transfer, 4th edn., John Wiley & Sons, 1996.
 SIST EN 12667:2002. Thermal performance of building materials and products – Determination of thermal resistance by means of guarded hot plate and heat flow meter methods – Products of high and medium thermal resistance. https://doi.org/10.3403/02152153u
 SIST EN ISO 10456:2008. Building materials and products – Hygrothermal properties – Tabulated design values and procedures for determining declared and design thermal values. https://doi.org/10.3403/30134452