REVIEW ON THE PERFORMANCE ENHANCEMENT METHODS IN THERMO-ELECTRIC GENERATOR (TEG) BASED ENERGY HARVESTERS FROM ASPHALT PAVEMENTS

Abstract

Asphalt pavements receive a lot of solar radiation from the sun, which is converted into thermal energy in the pavement, leading to the heating and softening of the pavement material, thus affecting its longevity. Also, in urban areas where these pavements form up to 40% of the land area, it leads to a phenomenon called the urban heat island (UHI). Thermoelectric generators (TEGs) can convert the thermal energy in the pavement into useful electrical energy for other applications, thus preventing these effects and also being a source of energy. The use of TEGs has the potential of solving these problems, and researchers have been working on developing TEGs for energy harvesting from asphalt pavements. The reported efficiencies of these systems are very low, and there is a need for improving the efficiency and power density of these devices. Thus, this paper firstly provides the details of the technology for energy harvesting from pavements and also provides an up-to-date review of the various strategies that are employed in improving the performance of the TEGs in asphalt pavements. These strategies include improving the thermoelectric properties of the TEG module or material; enhancing the thermal conductivity within the asphalt pavement; TEG system design and optimization; and increasing the temperature difference between the hot and cold sides by employing a well-designed heat sink. All these performance enhancement methods were found to improve the performance of the TEG system. The reported efficiencies of TEG systems embedded in asphalt pavements are still below 10%, and thus there is a need to improve the efficiencies. Additionally, most of these studies are either numerical or tested in laboratory prototypes.