Integration and optimisation of bio-fuel micro-tri-generation with energy storage

Abstract

This study addresses the global technical challenges of resource depletion and climate change by developing the first demonstration of incorporating smart energy storage (super-capacitors and batteries) with bio-fuel micro-tri-generation (BMT-HEES) for domestic applications. The developed system is capable of producing required heat, electricity and refrigeration from renewable bio-fuels for an average British household usage, and dynamically regulating the energy distribution within the system by using a novel energy storage system and a following electric load (FEL) energy management method. In this study, an extensive literature review has been carried out to investigate previous trigeneration and hybrid energy storage systems with a particular focus on their features, advantages and challenges which provide a basis for further improvements. The research work started with a preliminary investigation to fully understand the dynamic characteristics of lead acid batteries and super-capacitors used in combination to provide the desirable electrical output. The test results suggested that the super capacitors performed better than batteries in meeting transient electrical demands. In order to develop a complete BMT-HEES system, computational modeling and simulation was then conducted in the Dymola simulation environment, where the complete BMT-HEES system with advanced operational strategies has been implemented followed by case studies. System performance was assessed by evaluating key performance indicators including fuel consumption, dynamic response of each power sources, operational durations and energy efficiencies. A full experimental setup of the proposed system was also developed. Experimental tests on individual components and the BMT-HEES system as a whole have validated the effectiveness of the developed methodologies and techniques. Specific case studies have proved that the system can improve over the existing ones in terms of energy efficiency (with 47.86% improvement compared to one tri-generation system without HEES) and dynamic response for selected days as reported in the case studies. Test results from both simulation and physical experiments show that BMT-HEES can satisfy the fluctuating energy demands faithfully and instantly with high system efficiency for domestic applications. In addition, the predicted performance based on the developed methodologies has a good agreement with actual measurements. The low error of each assessment indicator provides iii the confidence that the system models can predict the system performance with good accuracy (all of the errors were within 3%). The developed technologies in this study can help cut down the carbon footprint in domestic environments, facilitate a shift towards an environment-friendly lifestyle, and in the long run, improve the quality of human life. Moreover, the established system is flexible, scalable and inter-connectable. That is, the system can incorporate other types of bio-fuels or other sources of new and renewable energy (wind, solar, geothermal, biomass etc.), depending on the availability of the energy and location of the system used. In addition to the small-scale domestic environment, the physical system can be scaled up to be used in larger commercial and industrial environments. It may be used as a stand-alone energy system or it can be interconnected with neighboring energy systems or connected with the power grid as a distributed generation set if there is a need (or a surplus) of generated electricity. Without doubt, this will require further work on this inter-disciplinary topic as well as new innovations in the fields of energy networks and smart grids.