Designs of MFC

Figure 1 also makes it clear that the behavior of an MFC system can be quite complicated, because the control action is determined as the result of the on-line optimization problem. Although engineering intuition may frequently be used in the analysis of the behavior or in the design of MFC systems, theory can provide valuable help. Theory can augment human judgement and intuition in the development and implementation of better MFC systems that can realize their full potential as advanced control systems. Some of the benefits of improved MFC systems are better control performance, less down time, reduced maintenance requirements, and improved flexibility and agility. 

MFC consists of an anodic chamber and cathodic chamber separated by CEM. The common designs of MFC include a single compartment, double compartment, upflow mode and stacked microbial fuel cell. The single compartment MFC possesses only one chamber, i.e., the anodic chamber. The cathode is either coupled to the anode, fabricated directly on the CEM or in tubular geometry with the anode. Figure 1.20a shows the single compartment MFC. 

The above analysis demonstrates that we are still below maximum power densities based on surface areas, but the design of MFCs will require systems that are efficient at power generation on a volumetric basis. Ultimately, the upper limit for power generation by bacteria is that of a single cell. If we had no mass transfer limitations, bacteria grew at the maximum rate, and there was no space between bacteria, then we would have the maximum volumetric power density. We can calculate this upper limit using assumptions about cell growth rates and cell size, as shown in the example below... 

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