Domestic and commercial fuel cell / battery / ultra-capacitor / thermoelectric hybrid power energy conversion and energy storage management CCHP system

Abstract

South Africa and by and large Africa, have been experiencing dire electrical energy crisis with unstable national grids which have led to load shedding (power rationing) from time to time and consequently inconveniencing many people’s lives and livelihoods. As a result of this, various sustainable energy initiatives focusing on renewable/alternative energy, have been commissioned to supplement the national grid and for private use. However, renewable energy systems suffer from inefficiency at various levels, since it involves various hybrid power and energy conversion technologies and systems. In light of these developments, my research was undertaken to investigate the energy conversion inefficiency problem and the objectives were defined which include; to propose and model an innovative hybrid power energy conversion scheme, enhance the energy / power inefficiency at component(s) or system levels and if possible justify the merits practically. To achieve this, an extensive literature review was conducted on combined, cold, heat and power (CCHP) systems, fuel cells, thermoelectricity and power converters as well as energy management systems. A research design and methodology was devised which constitutes a proton exchange membrane fuel cell and thermoelectricity CCHP system aided with Lithium ion battery and ultra-capacitor as well as power converters and energy management system. The postulated system was modeled and simulated using MATLAB and Simulink and deeper research was focused on the thermoelectricity section − which became the primal point of my research. Thermoelectric devices (generators and coolers) can produce power, cold and heat; however, their efficiencies are limited by their i) intrinsic figure of merit and further, their ii) practical design and implementation. Only the manufacturers can improve the former; however, the latter can be enhanced by the system or application researcher, hence thermoelectricity with and without heatsinks was comprehensively modeled using MATLAB / Simulink to understand their theoretical and practical functioning, optimal operations and configurations at module and system levels. Various unique findings and novel results were presented on how to improve the thermoelectric generator (TEG) output power and thermoelectric cooler (TEC) cooling power as well as their respective conversion efficiency and coefficient of performance. My research scientific contributions are summed up in ten research articles, in which numerous MATLAB / Simulink models of thermoelectricity were created and validated, new formulas were derived and validated as well as the proffered innovative CCHP system was modeled. However, due to procurement delays, the practical system was not designed and tested to demonstrate physically my research findings and hence, it is recommended as the next logical step for further studies.