Enhancing power generation by maintaining operating temperature using Phase Change Material for Microbial Fuel Cell application

Abstract

The present study focuses on the feasibility to provide power to sensors or environmental monitoring devices that are at remote locations through Microbial Fuel Cell (MFC). In field applications of MFC, fluctuations in temperatures during day and night lead to a decrease in overall performance, especially in locations where the temperature is highly vulnerable to change. To maintain required optimum temperature the use of capric acid, as a Phase Change Material (PCM) is proposed. Capric acid is incorporated into the MFC by enclosing the setup on the exterior so that only the PCM is exposed to external environment. During increase in external temperature capric acid melts gradually by absorbing heat and stores it acting as an insulator to the interior MFC unit. During decrease in external temperature, the PCM dissipates the stored energy to maintain the internal temperature by changing its phase from liquid to solid. Hence, the optimum temperature maintained provides a conducive environment for the growth and metabolism of microbes thereby resulting in a better electron transfer mechanism. The incorporation of capric acid resulted in a maximum voltage, power density, and coulombic efficiency of 728 ± 2 mV, 283 ± 1.3 mW/m2, and 8.6 ± 0.4%, respectively, unlike the MFC without capric acid (power density: 156.7 ± 1.5 mW/m2, voltage: 456 ± 1.3 mV and coulombic efficiency: 1.6 ± 0.2%) which suffered performance deterioration. The results revealed that capric can be used in integration with MFC to sustain optimum operating temperature. The study opens a new line of research to utilize other PCMs in MFC for thermal management.