Modeling and Validation of the Micro Photosynthetic Power Cell Harvesting from Blue Green Algae

Abstract

Introduction: The ever-growing need for energy is becoming an inevitable concern in today’s life. Amongst various source of new energy sources and more specifically energy harvesting systems, the biological-base energy harvesters have been attracting attentions within the past few years. Utilization of photosynthetic microorganisms as the heart of energy harvesting system is a new technology which is still under development and study. Micro photosynthetic power cell (mPSC) is one such system that works based on harvesting electricity from the photosynthesis of living microalgae culture which has been under study for several years[1].There are several advantages in implementing mPSC over other conventional energy harvesting systems including photovoltaic power cell and this is due their nature of operation. mPSC technology is cleaner than many other energy harvesting systems as it uses biological organisms as the main source of energy. Moreover, mPSC can operate in both light and dark conditions which makes it a reliable source for low-power applications and sensors that requires continuous power supply. Due to the newness of this technology, the development and optimization of these systems are still in research. Principle of Operation: Micro photosynthetic power cell (uPSC) is an electrochemical cell that produces electricity at micro scale. During the light condition, a living microorganism culture use light to consume carbon dioxide and water to produce electricity and during dark condition, the produced glucose, disintegrates with the help of oxygen and as a result, the electrical power will be generated[2].Figure 1 provides a general schematic of the operation of uPSC. Same as the regular fuel cells, mPSC consists of two chambers known as anode and cathode chambers which are separated with a proton exchange membrane (PEM). PEM is responsible for letting positive hydrogen ions, more specifically protons to pass through itself from anode side to cathode side. On both sides of the membrane, porous electrodes have been placed to collect electrons from anode and release them in cathode chamberIn anode chamber, microorganisms which in this research is living microalgae culture perform photosynthesis in which during a complicated process, electrons and positive ions released. The released electrons near membrane surface then will be transferred to an external circuit for power generation. During the daytime, the cells do photosynthesis and in dark condition, they reverse the process also known as respiration and electrons will be released during both the processes.In the cathode side, the electrons will reduce the catholyte Potassium Ferricyanide to Potassium Ferrocyanide. In the same time, the transferred protons will oxidize back the reduced catholyte and with their combination with oxygen, water will be released. Methodology: This paper, discusses the simulation of the uPSC using COMSOL Multiphysics in a similar way as with the general fuel cell operating concepts. The geometry is provided in Figure 2. This simu...