Evaluation of a roadway thermoelectric energy harvester through FE analysis and laboratory tests

Road surfaces are exposed to solar radiation that generates thermal gradients and heat flow in the pavement layers. The heat stored can be harvested providing an untapped source of renewable energy. This paper presents the design, construction, and assessment of an improved thermoelectric energy system prototype for harvesting heat energy from roadway pavements. To accomplish this, various prototype designs were simulated using Finite Element (FE) analysis, followed by design construction and laboratory testing of the most promising prototypes to evaluate their power harvesting capabilities. The main design components of these prototypes are a heat collector/transfer plate, thermoelectric generators (TEG), and a cooling module consisting of a heat sink, phase change material (PCM), and an insulation box. The results suggest a direct relationship between thermal gradients and power generation and point out the importance of the cooling module in maintaining the efficiency of the harvester. An optimum harvester design can produce a maximum power output of 30.41 mW over a period of 7 hours of summer sunshine in South Texas. Extrapolating this output for an installation that covers a length of 1 kilometre of a roadway could produce an average of 5.4 kWh/day under the conditions described above.