A Study on the Thermal Conductivity of Graphite Composite Insulation Material for Building Insulation

Global climate change has placed a heavy burden on the environment, with building energy consumption gradually emerging as a major environmental stressor. Therefore, energy conservation and emission reduction in buildings have increasingly become key issues of great concern. In regions with hot summers and cold winters, building envelope structures often use insulation materials to facilitate energy efficiency in buildings. Graphite composite insulation material (GCIM), a high-performance building insulation composite material, is composed primarily of graphite polystyrene particles (GPPs), glass microspheres (GMs), cement, and silica fume (SF). The thermal conductivity (TC) is an important parameter that affects its insulation performance. The volume ratios (VRs) of the material components will have a significant impact on its TC. However, there is currently a relative lack of theoretical research on the influencing factors of its TC, and its TC mechanism is not very clear. Therefore, a novel series-parallel alternate heat conduction theoretical model (SPAM) was established in this paper. The theoretical calculation expression for the TC of GCIM was derived using Fourier’s law of heat conduction. Through numerical simulation, three models comprising a total of 60 finite element (FE) models were constructed. The results of the numerical simulation were compared with theoretical calculations to further determine the influence of material component VRs on the TC of GCIM. The research results indicate that in the three established conventional models, the TC of GCIM decreases rapidly in the early stages and then stabilizes later, with a critical point at Ψ1Ψ2=Ψ1Ψ4=5. Within the specified range of VR variations, the value of Ψ1Ψ2 has the greatest impact on the TC performance of GCIM, followed by Ψ1Ψ4, while Ψ1Ψ3 has the smallest impact. The research findings will guide the material composition of the GCIM, reduce their TC, enhance their insulation performance, decrease building energy consumption, and hold high theoretical and practical value. This research will provide a theoretical reference basis for the widespread application of the GCIM in the field of building insulation.

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