Comparison of real‐time methods for maximizing power output in microbial fuel cells

Abstract

Comparison of real-time methods for maximizing power output in microbial fuel cells Woodward, L.; Perrier, M.; Srinivasan, B.; Pinto, R. P.; Tartakovsky, B.Contact us / Contactez nous: nparc.cisti@nrc-cnrc.gc.ca. Microbial fuel cells (MFCs) constitute a novel power generation technology that converts organic waste to electrical energy using microbially catalyzed electrochemical reactions. Since the power output of MFCs changes considerably with varying operating conditions, the online optimization of electrical load (i.e., external resistance) is extremely important for maintaining a stable MFC performance. The application of several real-time optimization methods is presented, such as the perturbation and observation method, the gradient method, and the recently proposed multiunit method, for maximizing power output of MFCs by varying the external resistance. Experiments were carried out in two similar MFCs fed with acetate. Variations in substrate concentration and temperature were introduced to study the performance of each optimization method in the face of disturbances unknown to the algorithms. Experimental results were used to discuss advantages and limitations of each optimization method.

The influence of operational conditions on the performance of a microbial fuel cell seeded with mesophilic anaerobic sludge

“…However, a cautious approach should be taken as to avoid MFC operation at external resistances below the internal resistance value as this results in the abrupt performance decline. In this regard, an on-line control of electric load must be considered in order to maximize MFC power output at varying operating conditions [31,32].…”

The effect of real-time external resistance optimization on microbial fuel cell performance

“…external resistance) thereby always producing the maximum power output (Woodward et al, 2010). As in any electric power source, maximum power is drawn when the external resistance (R ext ) equals the power source's internal resistance (Fuel Cell Handbook, 2005).…”

Microbial Fuel Cell Operation With Periodic Connection of the External Resistance

“…This change of R int requires electrical load to be adjusted in order to avoid MFC operation at R ext values significantly below the R int value and, consequently, a loss of power output (Pinto et al 2011;Woodward et al 2010). MFC operation with periodic connection of R ext enables MFC operation at R ext values below R int .…”

“…During the second test the same acetate load profile was used, while the external resistance was controlled by the P/O algorithm described in Woodward et al (Woodward et al 2010). Real-time optimization of R ext led to a higher power output at low OLR (Fig.…”

“…weekly or daily, while the internal resistance could significantly change within minutes, thus leading to significant energy losses. Recently, Woodward et al (2010) proposed a method for external resistance control, which uses an on-line perturbation/observation (P/O) algorithm for maximizing the power output. Also, a logic-based control approach for adjusting the external resistance was recently proposed (Premier et al 2011).…”