Thesis (Ph.D.)--Ohio State University, 2008. / Includes vita. Includes bibliographical references (p. 184-193). Also available online.

Thesis (Ph. D.)--University of Hong Kong, 2005.

Thesis (M. S.)--Mechanical Engineering, Georgia Institute of Technology, 2006. / Dr. Jerome Meisel, Committee Member ; Dr. Bill Wepfer, Committee Member ; Dr. Samuel V. Shelton, Committee Chair.

Thesis (M.S.)--University of Toledo, 2009. / Typescript. "Submitted as partial fulfillment of the requirements for The Master of Science in Mechanical Engineering." "A thesis entitled"--at head of title. Bibliography: leaves 75-78.

published_or_final_version / abstract / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

As the world's major car-producing countries and companies are increasing research and development efforts on vehicle electrification, electric vehicles (EVs) are developing rapidly from the development and testing stage to commodity production and application stage. As the largest global vehicle manufacturer and new vehicle market, China has considered the EV as one of the key tools to solve the increasing energy security issues and environmental pollution issues in the road transport sector. However, as a new market, what the challenges and key factors are in the EV promotion process is still not clear. The main objective of this dissertation is to answer this question through evaluating the effectiveness of EV development in China on energy savings, environment protection and policy demonstration. Instead of covering all determinants, this dissertation mainly focuses on four key aspects: the current statues and issues surrounding China's EV development and promotion; the energy consumption and carbon emissions of EVs based on the power mix both at the state level and regional level; the potential diffusion trend of the EV penetration and the sensitivities of the key impact factors; and the evaluation of the effectiveness of the EV demonstration program in China. Applying a mix of qualitative and quantitative research methods (such as lifecycle analysis, diffusion model and evaluation framework), this dissertation found that, in addition to the technology limitation of the EV, there are still many issues surrounding the environmental, industry, infrastructure and policy aspects, which have hindered EV development in China. To accelerate EV promotion, more comprehensive and diversified policy strategies should be developed instead only focusing on the financial subsidies. The charging infrastructures, for example, showed a more important role in EV penetration than the pricing factors, based on current market conditions. For the energy and environmental motivations, although the pure battery EV (BEV) can achieve a great reduction in fossil energy consumption, its benefits in carbon emission savings is not obvious due to China's heavy reliance on coal-fired power generation. The plug-in hybrid EV (PHEV) seems to be the right choice as a transit technology, according to its performance with emission savings in the current market situation. An evaluation framework has been developed in this dissertation to discuss the effectiveness of the EV demonstration program in China, and help to guide a more balanced development of EVs by considering comprehensive aspects, which include the EV industry, market conditions, policy support, and environmental impacts. Ultimately, this dissertation provides recommendations for the policy implementation for developing a diversified and flexible policy strategy for the EV penetration in China based on different technology choices (EV types), different situations (national and regional) and different timelines (short-term, mid-term and long-term).

Electric vehicles (EVs) are used instead of fossil fuel-burning vehicles to reduce greenhouse gases. The increased rate of utilizing EVs has an impact on the electric power system. This is due to the fact that EVs are loads that increase the peak demand. From these perspectives, this thesis studies the load of the electric chargers in a parking house in Uppsala and studies the effect of adding battery storage systems. The cost of used electricity is also calculated at different battery storage system (BSS) capacities, and the electricity bill is evaluated at these different conditions.  The data used in this work was collected from a parking house allocated in Uppsala city in 2021. It is equipped with 30 charging stations and 60 charging points in total. In addition, the parking house is connected to a PV system with two racks of batteries with a capacity of 137kWh. The surplus power generated by the PV system is sold to the grid. The data from the PV production and EVs demand is analyzed using MATLAB. The electricity price used in this study is from a standard contract from Vattenfall, with different prices at day and night (0.144 SEK/kWh at night and 0.48 SEK/kWh during day time). The battery is charged during the night, at a lower price, and discharges during the day. The excess power from the PV is also stored in the battery as self-consumption is more profitable than selling it to the grid.  The results show that the installed BSS units reduce the overall cost of the load as compared to those without BSS units. By studying the system under different battery capacities, the electricity bill is reduced to a certain limit. However, the increase in storage capacity beyond 137 kWh has no effect on the overall electricity cost. This maximum limit of the BSS unit's capacity would be greatly affected by the size of the installed PV system and the number of EVs to be charged. Controlling the charging and discharging periods has a significant impact on reducing the system cost.

Thesis (MScEng) -- Stellenbosch University , 2001. / ENGLISH ABSTRACT: In an effort to improve the fuel efficiency and to reduce emission levels of automobiles, the development of Hybrid Electrical Vehicles (HEVs) has been a major focus area of the automotive industry. The Centre of Automotive Engineering (CAE) at the University of Stellenbosch in conjunction with the Electric and Industrial Engineering Departments are currently developing an HEV. For this thesis, however, the focus is limited to the utilization of Pulsating Heat Pipes (PHPs) for the purpose of the thermal management and control of HEV components. As part of the study of PHPs a theoretical model is developed to simulate the heat transfer rate of PHPs. Several experiments were devised to assist in the understanding of the operating principles of PHPs. An experiment was conducted to determine the average thickness of the liquid film deposited at the trailing end of a liquid plug as it moves down a vertically orientated glass capillary tube under gravity. It was found that the average liquid film thickness varied between 100 and 200 |im for water. The movement of a liquid plug in a vertically orientated U-shaped capillary tube due to gravity and heat transfer was experimentally investigated. It was possible to observe the deposition and the evaporation of a liquid film at the trailing end of the liquid plug with the naked eye. The movement of the liquid plug was then theoretically determined and compared to the experimental results. The theoretical model did not predict the exact movement of the liquid plug but the final steady state values was predicted within 7.39%. The movement of a liquid plug in a horizontally orientated straight capillary tube was experimentally investigated. It was noticed that the plug exhibited a wide variety of movement ranging from irregular oscillations with amplitudes of ~ 50 mm to more steady oscillations with amplitudes of ~ 1 mm. Again it was possible to observe the deposition and evaporation of a liquid film at the trailing end of the liquid plug with the naked eye. A PHP was manufactured using glass and filled with pentane as the working fluid. This made it possible to visually observe the fluid motion inside the PHP. It was found that the liquid plugs moved in an irregular oscillatory manner. It was also observed that two plugs Stellenbosch University http://scholar.sun.ac.za/ sometimes coalesce to form a single plug and that a plug can split up to form two separate plugs. The heat transfer rate was determined for a stainless steel closed end PHP and an aluminium closed loop PHP for different working fluids, power inputs, filling ratios and inclination angles. It was found that the overall heat transfer coefficient varied between 100 and 500 W/m K for the stainless steel closed end PHP using water. The overall heat transfer coefficient varied between 0 and 400 W/m2K for the aluminium closed loop PHP using water. It was found that the stainless steel closed end PHP with ammonia as working fluid was not able to transfer heat in the top heat mode. The inside diameter of the tube (3.34 mm) exceeds the required diameter of 2.96 mm which prevents liquid plugs and vapour bubbles to form causing the PHP to operate similarly to a thermosyphon. The overall heat transfer coefficient varied between 170 and 3000 W/m2K. It is concluded that the experimentally determined heat transfer coefficients can be used to design similar PHPs in the future. The theoretical model was used to predict the heat transfer rate of the stainless steel closed end PHP. The experimental heat transfer rate in the top heat mode was 61 W compared to 60 W predicted by the theoretical model. In the bottom heat mode the experimental heat transfer rate was 63 W compared to the predicted value of 90 W. The theoretical model currently only caters for closed end PHPs. It is recommended that the model be extended to include closed loop PHPs. The internal diameter of the PHPs is too great for ammonia to be used as working fluid. It is recommended that a PHP be constructed with dt < 2.5 mm to allow for ammonia to be used as working fluid. Concepts were generated for the thermal management of selected HEV components. A concept was developed for the thermal management of the HEV batteries. It was found that a Stereo-type heat lane can provide promising solutions for the thermal management of Insulated Gate Bipolar Transistors (IGBTs). / AFRIKAANSE OPSOMMING: In ‘n poging om voertuie se brandstof-benuttingsgraad te verbeter en die vlakke van uitlaatgasse te verminder word daar deur die motorvoertuigindustrie gefokus op die ontwikkeling van ‘n Hibriede Elektriese Voertuig (HEV). Die Centre of Automotive Engineering (CAE) aan die Universiteit van Stellenbosch in samewerking met die Elektriese - en Bedryfsingenieurswese Departemente is tans besig met die ontwikkeling van ‘n HEV. Die fokus van hierdie tesis is egter beperk tot die gebruik van Pulserende Hittepype (PHPe) vir die doel van die termiese beheer van HEV komponente. As deel van die studie van PHPe is ‘n teoretiese model ontwikkel waarmee die warmte oordragstempo van PHPe simuleer kan word. Verskeie eksperimente is prakseer om die beginsels waarvolgens PHPe werk, beter te verstaan. ‘n Eksperiment was uitgevoer om die gemiddelde dikte van die vloeistof-film wat gedeponeer word by die agterkant van ‘n vloeistofprop wat in ‘n vertikaal georienteerde kapillere pypie onderworpe aan gravitasie, beweeg. Dit was gevind gewees dat die gemiddelde dikte van die vloeistof-film het gewissel tussen 100 en 200 (im vir water. Die beweging van ‘n vloeistofprop in ‘n vertikaal georienteerde U-vormige kapillere pyp as gevolg van gravitasie en warmte-oordrag was eksperimenteel ondersoek. Dit was moontlik gewees om die deponering en verdamping van ‘n vloeistof-film by die agterkant van die vloeistofprop met die oog te sien. Die beweging van die vloeistofprop was teoreties bepaal en vergelyk met die eksperimentele resultate. Die teoretiese resultate het nie die presiese beweging van die vloeistofprop voorspel nie maar die finale gestadigde posisie was voorspel binne 7.39%. Die beweging van ‘n vloeistofprop in ‘n horisontaal georienteerde reguit kapillere pyp was eksperimenteel bestudeer. ‘n Wye verskeidenheid van beweging van die vloeistofprop was waargeneem wat wissel van onreelmatige ossilasies met amplitudes van ~ 50 mm tot meer reelmatige ossilasies met amplitudes van ~ 1 mm. Die deponering en verdamping van die vloeistof-film by die agterkant van die vloeistofprop was weereens met die oog waargeneem. ‘n PHP was van glas vervaardig en met pentaan gevul as die vloeier. Dit het dit moontlik gemaak om die vloeistofbeweging binne die PHP visueel waar te neem. Dit was gevind gewees dat die vloeistofproppe in ‘n onreelmatige ossilerende wyse beweeg. Dit was ook waargeneem dat twee vloeistofproppe somtyds saamsmelt om een vloeistofprop te vorm en dat ‘n vloeistrofprop kan opbreek om twee aparte vloeistofproppe te vorm. Die warmte oordragstempo was bepaal van ‘n vlekvrye-staal geslote ent PHP en van ‘n aluminium geslote lus PHP vir verskillende vloeiers, drywing insette, vulverhoudings en inklinasie hoeke. Die algehele warmte oordragskoeffisient was tussen 100 en 500 W/m2K vir die vlekvrye-staal geslote end PHP gevul met water en tussen 0 en 400 W/m2K vir die geslote lus aluminium PHP gevul met water. Dit was gevind gewees dat die vlekvrye-staal geslote ent PHP gevul met ammoniak nie in staat was om warmte oor te dra in die boonste verhittingsmodus nie. Die binnediamter van die pyp (3.34 mm) is groter as die vereiste diameter van 2.96 mm wat verhoed dat vloeistofproppe en gasborrels gevorm word wat veroordaak dat die PHP soortgelyk aan ‘n termoheuwel werk. Die algehele warmte oordragskoeffisient was tussen 170 en 3000 W/m2K. Die eksperimentele bepaalde waardes vir die warmte oordragskoeffisiente kan gebruik word vir ontwerpdoeleindes van soortgelyke PHPe in die toekoms. Die toeretiese model was aangewend om die warmte oordragstempo van die vlekvrye staal geslote end PHP te bepaal. Die eksperimentele warmte oordragstempo in die boonste verhittingsmodus was 61 W in vergeleke met die teoretiese waarde van 60 W. In die onderste verhittingsmodus was die eksperimentele warmte oordragstempo 63 W in vergeleke met die voorspelde waarde van 90 W. Die teoretiese model kan huidiglik slegs geslote ent PHPe simuleer. Dit word aanbeveel dat die model uitgebrei word sodat dit geslote lus PHPe ook kan simuleer. Die binne diameter van die PHPe is te groot om ammoniak te gebruik as vloeier. Dit word aanbeveel dat ‘n PHP vervaardig word met d, < 2.5 mm sodat ammoniak ook gebruik kan word as vloeier. Verskeie konsepte was gegenereer vir die termiese beheer van geselekteerde HEV komponente. ‘n Konsep was ontwikkel vir die termiese beheer van die HEV batterye. Dit was gevind gewees dat ‘n Stereo-type heat lane belowende oplossings kan bied vir die termiese beheer van Insulated Gate Bipolar Transistors (IGBTs).

The shift towards more renewable energy sources is imminent, this shift is accelerated by the technological advancement and the rise of environmental awareness. However, this shift causes major operational problems to the current grid that is optimised for unidirectional power flow. Besides the operational problems, there are problems related to the optimal tariff scheme. In this thesis a study on the effect of the adoption of photovoltaic solar panels and the electric vehicles on the households' electricity demand profile is presented. The change on the demand profile is going to affect the current tariffs, this effect is also explored in this thesis. In this thesis real life data on household electricity use and photovoltaic power production was used. For electric vehicle charging simulated data was used. Besides that, a demand response scheme for electric vehicle is proposed in order to estimate the savings potential of this demand response on the electricity bill. The results show that the change in the demand profile is not merely a change in the total energy consumption, but it is a change in the power peaks as well. The peaks change significantly in condominiums and rental apartments, in this households' type it increases by around 80%, while in detached and row houses little change is noticed on the peaks, yet they still increase by around 10%. The demand response shows around 1- 12% savings in the distribution bill depending on the household, however it showed more incentives for condominiums and rental apartments. The current distribution tariffs perform asymmetrically with the various households. However, one tariff ensures 11.7 MSEK financial revenue for the distribution system operator, this is higher than the other tariffs' revenue by more than 28.5%. The new prospective situation requires totally different tariffs that ensure a balance between firstly a reasonable revenue for the distribution system operator and secondly incentives for consumers to self produce electricity as well as to reduce their peaks.

published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy