Asphalt Pavements – Kim (Ed) © 2014 Taylor & Francis Group, London, ISBN 978-1-138-02693-3 1827 Optimization of thermoelectric system for pavement energy harvesting Philip Park, Gwan S. Choi, Ehsan Rohani & Ikkyun Song Texas A&M University, College Station, TX, USA ABSTRACT: With the increasing emphasis on renewable resources and green technolo- gies, energy harvesting from asphalt pavement has gained momentous attention in the recent years. Thermoelectric energy harvesting is one of the promising methods for collecting and transmitting solar energy into electrical power using temperature gradient along the pave- ment depth. However, the low energy conversion efficiency must be mitigated in order for this method to be viable for various practical applications. Henceforth, the objectives of this study are to investigate the key factors affecting the energy conversion efficiency and to derive opti- mal mechanical and circuit configurations. The goal is to compose a thermoelectric energy harvesting system tailored for the pavement application. The design under study is typical and it consists of a thermoelectric generator and thermally conductive rods for transferring heat. The effects of the generator type, circuit design, the shape of the conductive rod, and its insulation are investigated. The results indicate that the controlling of the heat transfer from the pavement to the thermoelectric generator is central to effective thermoelectric energy harvesting. Among the tested thermoelectric systems, the best device configuration yielded 42 mW; about 26 times higher power than the default case in this study. Keywords: Energy harvesting, pavement, thermoelectric generator, optimization 1 INTRODUCTION Transportation system is one of the largest and most important infrastructures in modern society. According to Federal Highway Administration (FHWA), a total lane mile of the public roads in the US is 8.6 Million miles in 2012 [1]. In the US, 28% of total produced energy was consumed by transportation sector in 2012. While the moving of vehicle is the major energy consumption of the transportation sector, the transportation facilities uses 25 × 10 12 BTU of electrical energy for the roadway lighting, signal, and various sensing and monitoring systems [2]. Additionally about 51 × 10 12 BTU, which is about twice that actually consumed, is lost from transmission during power delivery. This is caused by the widespread nature of roadways. Energy harvesting reclaims otherwise dissipated or wasted energy, and is highly sustainable power generation approach. While energy harvesting technology has successfully been explored in numerous electronics and mechanical systems applications, its application to roadway pave- ments is currently at its infancy. Since asphalt pavement is a huge storage of solar energy, the pavement energy harvesting technology promises a significant breakthrough in attaining renew- able energy at a massive scale. The specific attributes of harnessing energy from pavements are: 1) the size of roadways is massive, and hence, relatively large amount of energy can be collected, 2) there exist various types of available energy sources, e.g. geothermal, solar, mechanical, etc., and 3) a long-distance power transmission is not necessary because the collected electrical energy can be consumed in place by traffic facilities. In situ generation of electrical power can decidedly offset the aforementioned transmission loss of electrical energy. In addition, it can eliminate the installation and maintenance cost of power delivery infrastructures.