Effect of Temperature and Density Variations on Thermal Conductivity of Polystyrene Insulation Materials in Oman Climate

The thermal and energy performance of buildings depends on the thermal characteristics of the building envelope and particularly on the thermal resistance of the insulation material used. The ability of a thermal insulation material to transmit heat in the presence of a temperature gradient is determined by its thermal conductivity. The thermal conductivity values of building insulation materials are generally given at 24°C according to ASTM standards. Actually, such a material when used in a building envelope is exposed to significant and continuous temperature changes, essentially due to the changes in outdoor temperature and solar radiation, especially in harsh climate. The main objective of this study is to investigate the relationship between the temperature and the thermal conductivity of polystyrene, which is widely employed as a building insulation material in Oman, at various densities, using the developed experimental setup based on the guarded hot plate method. The results show that higher temperatures lead to higher thermal conductivities and the lower is the material density, the higher is the thermal conductivity. The envelope-induced cooling load for a simple building is also calculated, and it is shown that a lesser cooling load is needed for a high-density insulation.