Harvesting heat energy from asphalt pavements: development of and comparison between numerical models and experiment

International Journal of Sustainable Engineering 06/2012; 5:159-169. DOI: 10.1080/19397038.2011.574742

ABSTRACT The use of flowing water in embedded pipes to harvest heat energy from asphalt pavements and thereby reducing its temperature and the urban heat island effect has been proposed. A successful use of such an approach would require a complete understanding of the effect and the interaction of various mechanisms such as conduction, convection and radiation and factors such as solar radiation, diameter of pipe and rate of flow. A large-scale experiment was conducted to understand such effects, and numerical modelling was conducted for prediction of temperature. The experiment was modelled using finite element method, and a good match was obtained between predicted and experimentally obtained results. Effects of pipe diameter and flow rate were also analysed. This model could be used in future for selection of appropriate levels of critical variables and hence successful implementation of this concept to sustainable pavements.

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    ABSTRACT: Hydronic asphalt pavement (HAP) is an emerging technology for the purpose of harvesting solar energy in the summer and deicing the pavement in the winter. Increasing the thermal conductivity of pavement material is a fundamental technology to improve the operation efficiency of such novel system. In this paper, the influences of graphite on the thermal characteristics and anti-ageing properties of asphalt binders were experimentally investigated. A control asphalt binder (CAB) sample was prepared by the same weight ratio of asphalt and mineral filler. Experimental results indicated that the thermal conductivity and diffusivity increased linearly with the increasing of graphite content, while the specific heat presented a descending trend correspondingly. Although the storage stability of asphalt binders with graphite were better than the CAB sample, binders with mineral filler or graphite showed bad high temperature storage stability. Differences between the physical and rheological properties of the original asphalt binders and the aged samples illustrated that graphite improved the anti-ageing properties of asphalt binders.
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