Construction of Continuous Energy Harvesting System from Low Grade Heat Using Electrode Flow Capacitors

Abstract

The conversion and reuse of Low-grade thermal energy (< 100 ℃) are attractive and a great challenge. Because of the poor efficiency of the previous thermal regeneration system, a significant portion of primary energy in the world is discarded as low-grade waste heat. For this point, it is reported that low-grade thermal regeneration cycle using electrode potential dependence on temperature in the electrochemical system. Since the reported thermal regeneration cycle is an intermittent cycle composed of four stages (charge-heat-discharge-cooling), there is a limit in that it cannot continuously generate energy. Herein, a continuous cycle was created by combining an intermittent cycle with a flow cell capacitor. Besides, by combining the power generation cycle based on the electrolyte concentration difference and the thermal regeneration cycle, it was constructed to form a continuous cycle without supplying external power. the flow electrode capacitor was optimized to form a continuous power generation cycle having an output density of 7.38 mW/m2. Continuous energy regeneration systems have the advantages of stable, steady-state operation, long life and scalability for grid-scale. In perspective, the proposed continuous energy harvesting system is expected to be installed in coastal industrial fields and to generate large amounts of energy.