Introduction

Micro-Photosynthetic Fuel Cell (μ-PSC) generates electrical power by continuously converting chemical energy with the help of the light into electrical energy through an electrochemical reaction. In µ-PSFC, both cell growth and cell decay occur in the anode chamber.

Motivation

Unconventional renewable energy source which are scarce and have not been explored thoroughly or exploited expansively. The photosynthetic power cell (PSC) with micro electrical power scales is considered as one of these resources. Although there are few prototypes fabricated earlier, there has not been a comprehensive electrical equivalent model developed yet.

Research Objectives

• To propose a mathematical model that depicts the interaction occurred in the three parts of the µ-PSC which are the anode, cathode and membrane (electrolyte) that in turn, produces electrons which are drawn outside the cell through an external load.

Figure (1) μ-PSC principle of operation

• To describe the principle of operation of the device that is based on photosynthesis and respiration. Both involve electron transfer chain.

                                                         Photosynthesis: 

                                                          Respiration:   

• To exemplify the mathematical model using electrical equivalent model which will be tested using PSIM and MATLAB/SIMULINK under different environmental conditions and electrical loads. The proposed model will then be verified experimentally using a fabricated prototype.

Figure (2) μ-PSC prototype fabricated in Concordia University’s lab

Simulation Results

•  The proposed equivalent circuit for photosynthetic power cell that can be simulated and also emulated in real-time is given below:

• The output voltage of the µ-PSC is measure by using the Nernst voltage equation:

     V_PSC  =  E_o – V_act – V_ohmic – V_conc

            E_o :      Open circuit voltage (Nernst reversible voltage)

           V_act :     Activation  voltage loss (barrier energy)

           V_ohmic :  Ohmic voltage loss (electrolyte and electrodes resistances)

• The the electro-chemistry operation can be represented by:

            In    

• While there is a large volume of electro-chemical research literature on, for example, electron transfer chains and redox processes in cell metabolism that is relevant to micro-photosynthetic fuel cell, relatively few studies focus specifically on modeling and equivalent circuit representation of μ-PSC. This is exacerbated by the fact that on-going research continues to identify new mechanisms for electron exchange between growth mediums and electrodes, new design stratifies to exploit these and consequently new candidate organisms.

• Such organisms have not been well studied experimentally before. So, a detailed simulation and experimental study will be carried out.