http://theses.ncl.ac.uk/jspui/handle/10443/1888 2026-02-04T10:56:10Z 2026-02-04T10:56:10Z Li, Yapeng http://theses.ncl.ac.uk/jspui/handle/10443/2824 2016-01-28T16:11:47Z 2015-01-01T00:00:00Z

Title: Dynamic energy demand prediction and related control system for UK households Authors: Li, Yapeng Abstract: Domestic energy consumption is not only based on the type of appliances, weather conditions, and house type; it is also highly depended on related occupancy profiles. In order to manage and optimise energy generation and the effective use of energy storage, it is important to be able to accurately predict energy demand in advance. However, high-resolution (like below 1-min) occupancy profiles for domestic UK households are not ideally possible to be recorded or measured in nature. Therefore, an alternative approach to transfer particular electricity load to the number of active occupancy during selected time interval is identified by analysing the average electricity consumption of occupancy in this study. Real load data analysis for three type of participated UK households is presented throughout the year. Then the seasonal synthetic high-resolution (30s) occupancy patterns for each household are generated independently. Weekday occupancy profiles are collected seasonally and used in a Markov-Chain model to produce particular occupancy daily activity sequence for each household. A stochastic model by using Markov-Chain Monte Carlo is presented to randomly generate high-resolution occupancy profiles in dynamic. Then the predicted electricity loads are produced by mapping occupancy profiles to average electricity consumption. By validating the predicted results, it is found that maximum of sub-hourly aggregate result can mostly cover the measured demand in advance. Therefore, it is set the sub-hourly electricity demand boundary independently for each household during weekday throughout the year. Heat demand for each household is simulated in sub-hourly resolution by using DesignBuilder with EnergyPlus throughout the year. Thus, sub-hourly energy demand of each household is applied in the control system of Bio-fuel Micro Trigeneration with Hybrid Electrical Energy Storage. The control system is designed and implemented by using Siemens software STEP-7 S-300 and WinCC. In addition, the predicted energy demands are utilized into the optimization of the control system. The comparison of optimized and general control strategies shows that optimized strategies by applying prescient sub-hourly energy demand can improve system efficiency significantly. Description: PhD Thesis

2015-01-01T00:00:00Z Chen, Xiangping http://theses.ncl.ac.uk/jspui/handle/10443/2126 2014-03-03T15:41:42Z 2013-01-01T00:00:00Z

Title: Integration and optimisation of bio-fuel micro-tri-generation with energy storage Authors: Chen, Xiangping 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. Description: PhD thesis

2013-01-01T00:00:00Z Yu, Hongdong http://theses.ncl.ac.uk/jspui/handle/10443/1889 2013-11-15T10:26:16Z 2013-01-01T00:00:00Z

Title: The design, testing and analysis of a biofuel micro-trigeneration system Authors: Yu, Hongdong Abstract: Trigeneration and the use of biofuels are two research topics which are important in trying to help relieve global energy shortage and bring about a reduction in greenhouse gas emissions. Trigeneration produces electricity, cooling, and heating simultaneously using a single fuel source and can operate at a high efficiency rate. The use of biofuel provides a renewable and carbon neutral substitution for fossil fuels. This research thesis describes the development of a biofuel micro-trigeneration (BMT) system using raw vegetable oils and explores the feasibility of meeting the total energy demand of a typical household. The system was designed and constructed using a 6.5kW single cylinder diesel generator as the prime mover, two heat exchangers for recovering waste heat from the engine coolant and exhaust gas, and an absorption refrigerator driven by exhaust gas heat. Four raw vegetable oils: sunflower, rapeseed, jatropha and croton oils were preheated to 90℃ and used in the study. The system performance using the vegetable oils was compared to that of the gas oil. Experiments were carried out to determine the fuel properties of the oils, including viscosity, density, higher heating value and fatty acid components. Power generation, combined heat & power and trigeneration tests were also carried out. The experimental results reveal that the BMT system performed with a high efficiency of 65% for trigeneration at full load, and CO2 emissions was reduced by around 60% compared to single power generation mode. The exergy efficiency was also increased by approximately 5 points. An engine model was developed using DIESEL-RK software to study the engine performance and emissions using different fuel types. Optimizations were performed to improve the engine performance and emissions. A trigeneration system model was also developed using Dymola software and was used to predict the dynamic performance of the system parameters. These models and simulation studies were validated against experimental results and matched well with the experimental results; hence can be used to explore wider system design and performance considerations. Both the experimental and theoretical studies have proved the feasibility of the BMT system to meet the overall energy demand of a household user. Description: PhD Thesis

2013-01-01T00:00:00Z