High-Performance Conformal Thermoelectric Generator for Environmental Monitoring

A continuous underground pipeline monitoring system is needed to avoid energy waste or pipeline explosions and minimize the negative environmental impact. Thermoelectric-powered Internet of things (IoT) sensors can be a promising solution due to reliable power sources supplied by thermoelectric generators to scavenge the wasted heat through the pipeline surface. Conformal thermoelectric generators (cTEGs) are suitable for pipeline applications; however, the current study is mainly focused on harvesting body heat, which is not suitable for piping systems because of the different thermal path. Here we designed and fabricated a film-based cTEG on a roll-to-roll manufacturing platform using an electrothermal model to achieve an optimized device structure and performance. The unique design of this cTEG device provides the capability of scavenging mid- to low-grade waste heat, which is the most common wasted heat source for underground pipeline systems. The proposed device fabrication method combines bulk TE elements with a flexible printed circuit board to maximize the power output and minimize the cost. The resulting power output density of a cTEG integrated with four pairs of p-n junctions is 1.26 mW/m(2) at a temperature difference of 50 degrees C, which is 2 times higher than the value reported in the current literature. This study provides a potential pathway for using TEGs as energy sources for powering underground pipeline monitoring systems in a cost-effective way for real applications.