Influence of conduction shape factor in subterranean cooling for a thermoelectric energy harvesting system at asphalt pavement: An experimental investigation

This research study's primary motivation is to study the practicality and feasibility of energy harvesting or energy scavenging using ambient energy such as heat absorbed by asphalt pavement to provide electrical power for small electronic circuits or devices, making them self-sufficient. Therefore, this project investigates the thermal distribution evaluation of multiple diameters of the aluminum rod as a cooling element and examines the optimum designs for the surface heat absorption method using the aluminum plate in the road thermoelectric energy harvesting system (RTEHs). The RTEHs experimental setup consisted of an asphalt-filled wooden base box, "sandwiched" thermoelectric module, top aluminum plate, and bottom aluminum rod, which is partially submerged in the asphalt and soil. Using constructed RTEHs setup and several thermocouples, a series of experiments on multiple diameters of an aluminum rod as a cooling element and few aluminum plate designs were conducted to obtain the best configurations that yield maximum temperature difference between cooling and heating sides in asphalt based RTEHs. Based on the testing results, RTEHs with a mounted triple of Rod C, which has the biggest diameter of 31.75 mm (1.25 inch) and combined with 100 mm x 200 mm of a top plate, proved to be the best performing configuration by producing the highest temperature difference (DT) of 15.19 degrees C. Since the triple rod configuration has a higher value of shape factor, this indicates a better heat transfer performance by conduction. These proved the theory of conduction shape factor for multiple geometries. Based on the results, having a bigger top plate as a heating element promotes a higher heat transfer rate and takes in more heat energy, thus producing the largest DT for the system, which confirmed Stephen-Boltzmann's law on radiation heat transfer.