Harvesting of thermoelectric energy from asphalt pavements
This study aims at developing a thermoelectric energy harvesting prototype for asphalt pavement roadways. This is an emerging research field which encompasses technologies that capture the existing thermal energy in pavements to generate electricity without depleting natural resources. In lower latitudes, such as South Texas, the asphalt pavement surface temperature in the summer as high as 55°C due to solar radiation. Soil temperatures below the pavement, however are roughly constant (i.e. 27°C to 33°C) at relatively shallow depths (15 cm). This thermal gradient between the surface temperature and the pavement substrata can be used to generate electrical power through thermoelectric generators (TEGs) modules. The proposed prototype collects heat energy from the pavement surface and transfers it to a TEG module embedded into the subgrade at the edge of the pavement shoulder. Evaluation of this prototype was carried out through finite element analysis, laboratory testing and field experiments. The results suggest that the 64mm x 64mm TEG prototype is capable of generating an average of 10 mW of electric power continuously over a period of 8 hours, for the weather conditions encountered in South Texas. Scaling up this prototype using multiple thermoelectric elements could generate sufficient electricity to sustainably power LED lights for signage, illumination or instrumentation.