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

International Journal of Sustainable Engineering 06/2012; 5(2):159-169. DOI: 10.1080/19397038.2011.574742


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.

Download full-text


Available from: Rajib B. Mallick, Oct 30, 2015
    • "As a consequence, and according to existing literature, an asphalt concrete PSC can harvest more thermal energy compared to cementitious concrete PSC's [3]. It was shown that a PSC can reduce the maximum pavement temperature by about 5 °C, which also leads to a reduction in surface temperature and thus emission of longwave radiation and convective heat transfer [8] [9]. A reduction of the maximum pavement temperature will reduce the potential rutting damage and fatigue due to oxidation of the binder in the case of asphalt concrete roads. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Current aims regarding environmental protection, like reduction of fossil fuel consumption and greenhouse gas emissions, require the development of new technologies. These new technologies enable the production of renewable energy, which is both cleaner and more abundant in comparison to using fossil fuels for energy production. This necessity encourages researchers to develop new ways to capture solar energy, and if possible, store it for later use. In this paper, the Pavement Solar Collector (PSC), and its use to extract low temperature thermal energy, is studied. Such a system, which harvests energy by flowing water through a heat exchanger embedded in the pavement structure, could have a significant energy output since pavement materials tend to absorb large amounts of solar radiation. The main objective of this paper is to develop a modeling framework for the PSC system and validate it with a self-instructed experiment. Such a model will allow for a detailed parametric study of the system to optimize the design, as well as an investigation on the effect of aging (e.g. decreasing solar absorptivity) on the performance of the system. A long-term energy output of the system that is currently lacking is calculated based on results of the study on weather parameters. This newly acquired data could be the start of a comprehensive data set on the performance of a PSC, which leads to a comprehensive feasibility study of the system.
    No preview · Article · Jan 2016
  • [Show abstract] [Hide abstract]
    ABSTRACT: As climate changes, the performance of pavements can be expected to change too. More rainfall can be expected to lead to softer subgrades and less support to the pavement structure with consequences for more rapid cracking and rutting. Even if the amount of rainfall doesn’t change, many places can expect the rain to fall in less frequent but more intense storms leading to challenges for current pavement drainage systems. If temperature rises, then asphaltic pavements may be expected to suffer from greater rutting in hot weather; but if the temperature rise causes greater evaporation then improved support conditions could arise; and if the temperature rise is in an area that historically experiences fully frozen conditions in the winter, then weak, thawing pavements could result. Predicting these and other effects of climate change involves an understanding of the sensitivity to climatic effects of both material properties and of overall pavement performance. In turn the predictions of such changes might indicate the need for adaptation in design, construction or materials selection—the extent of the need being dependent on the severity and risk associated with the predicted changes. In this way appropriate responses can be made to the challenges that future climate change will bring. In some places no change to practice may be required. However, for most authorities the immediate response should be to restate design codes and specifications with climate change in view. Mostly, the practices, techniques and tools for an adequate response are already available but users may need to employ adjusted practice if they don’t want future maintenance demands to become excessive.
    No preview · Chapter · Jan 2014
  • [Show abstract] [Hide abstract]
    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.
    No preview · Article · Oct 2014 · Construction and Building Materials
Show more