Experimental study on the influence of temperature and humidity on the thermal conductivity of building insulation materials

Abstract

At present, thermal conductivity is usually taken as a constant value in the calculation of building energy consumption and load. However, in the actual use of building materials, they are exposed to the environment with continuously changing temperature and relative humidity. The thermal conductivity of materials will inevitably change with temperature and humidity, leading to deviations in the estimation of energy consumption in the building. Therefore, in this study, variations in the thermal conductivity of eight common building insulation materials (glass wool, rock wool, silica aerogel blanket, expanded polystyrene, extruded polystyrene, phenolic foam, foam ceramic and foam glass) with temperature (in the range of 20–60 °C) and relative humidity (in the range of 0–100%) were studied by experimental methods. The results show that the thermal conductivity of these common building insulation materials increased approximately linearly with increasing temperature with maximum growth rates from 3.9 to 22.7% in the examined temperature range. Due to the structural characteristics of materials, the increasing thermal conductivity of different materials varies depending on the relative humidity. The maximum growth rates of thermal conductivity with humidity ranged from 8.2 to 186.7%. In addition, the principles of selection of building insulation materials in different humidity regions were given. The research results of this paper aim to provide basic data for the accurate value of thermal conductivity of building insulation materials and for the calculation of energy consumption.