Optimization of a Two-Level Thermoelectric System for Pavement Energy Harvesting

Abstract

For this study, we designed and optimized a two-level thermoelectric pavement energy harvesting system. The optimization was evaluated based on the cost per unit of energy ($/J) as the target function. The idea behind the two-level thermoelectric system is to use thermoelectric power generator (TEG) modules on different depths of pavement to maximize the heat exchange efficiency of temperature gradients created by both daytime and night-time conditions. As the temperature difference is the driving force for the flow of thermal energy through the TEG, and the TEG turns a certain percentage of thermal energy into electrical energy, the two extrema created by daytime and night-time temperatures have the most potential to generate electricity. Since the generated energy is entirely dependent on the temperature profile and thermal exchange between different elements of the device, and between the device and the environment below the surface, we had to develop tools to provide an accurate analysis of these exchanges. In addition, we created an accurate temperature profile by extrapolating from existing geological information. We calculated the associated costs and changes in total generated energy for each change in the design parameters using our evaluation model and determined their effect on the target function.