Experimental Investigations of Transport Properties of Natural Thermal Insulation Materials

Experimental Investigations of Transport Properties of Natural Thermal Insulation Materials

I. Conté X.F. Peng Y. Zhang 

Laboratory of Phase-Change and Interfacial Transport Phenomena, Department of Thermal Engineering, Tsinghua University, Beijing, China

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Experimental investigations were conducted to characterize the thermal insulation properties of different natural low-cost materials (coconut fi bers and groundnut shell). A steady state method was used to measure the thermal conductivity by holding the sample between two concentric spheres with heat transferred mainly by conduction from the inner sphere (heat source) through the testing material. For comparison, the same experimental procedure was done for a standard and man-made insulation material, aluminum silicate fi ber. The results showed that for all the materials, the thermal conductivity increases with temperature; and the rates of increase are very similar. Also, two experimental samples were made to measure the moisture transport of the two natural materials: one with groundnut shell (composed of void space and grain) and the other sample with coconut fi bers (composed of void space and fi bers). The percentage of water accumulation due to vapor absorption was calculated for each layer after a pre-set time of experiment (1 h, 2 h, …). A numerical investigation was performed to simulate the transfer process with a general and sound model, and to present the basic features of the transfer process.


 air and moisture transport, natural material, porous media, thermal conductivity, thermal insulation.


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