Thermal transport properties of synthetic porous solids as a function of applied pressure

The thermal conductivity, thermal diffusivity and specific heat per unit vo lume of three types of porous insulating solids were measured, simultaneous ly, by the transient plane source (TPS) technique. The samples, namely, fib reglass, dosed-cell foam and foam insulation, were subjected to external pr essure, taking into consideration the compressibility of the samples and th e requirements of the TPS technique. These materials are used for insulatio n for temperature control of air-conditioned space and therefore are helpfu l in reducing energy losses. Although all three samples are good insulators , having very small thermal conductivity values (similar to 0.03-0.05 W m(- 1) K-1), dosed-cell foam insulation shows insignificant changes in thermal conductivity for the selected pressure range (8-15 kPa). Therefore it is a better choice for thermal isolation. For the other materials investigated, the thermal conductivity value increases slightly with external pressure.