Inducing directional heat transfer by enhancing directional thermal conductivity of asphalt mixtures for improving asphalt solar collectors

Low thermal conductivity makes heat conduction in asphalt pavements quite slow, restricting asphalt solar collectors. To enhance the directional thermal conductivity of asphalt mixtures and induce directional heat transfer, directional heat-induced channels are built in asphalt mixtures by using carbon fibers with high axial thermal conductivity. A finite element method is used to simulate and study the temperature field and heat flow distribution of asphalt mixtures. A parametric analysis of the carbon fiber parameters is performed to evaluate the variation in the performance of the effective thermal conductivity of asphalt mixtures. The temperature trend of asphalt mixtures is measured by an indoor irradiation experiment and compared with the simulation results. The results show that heat-induced channels have obvious heat convergence effects and can induce heat to be efficiently conducted along its axial direction. These channels can significantly improve the directional thermal conductivity of asphalt mixtures and are expected to play a heat transfer bridge between the pavement surface and the energy collection system when using them in asphalt solar collectors in the future. (C) 2020 Elsevier Ltd. All rights reserved.