Thesis (Doctoral)--İzmir Institute of Technology, İzmir, 2005 / Includes bibliographical references (leaves 271-292).

The problems of excessive consumption of fossil resources, oil shortages and greenhouse gas emissions are becoming increasingly severe. Research and development work on new methods of thermal energy storage are imminently required. To effectively store seasonal renewable energy, a novel high capacity heat storage system has been designed and evaluated/validated through laboratory experiments and numerical simulations in this research. The system is driven by direct flow evacuated tube solar collector with enhanced PCM tank and intends to be applied in residential and commercial buildings. Theoretical and experimental approaches and numerical analysis have been employed in this study. Firstly, phase change materials (PCM) with specific heat density, melting point, melting and solidifying time have been investigated. This type of PCMs can maintain a considerable high internal temperature of environment chamber in a frozen ambient temperature. Numerical modelling has been conducted on a passive house (Nottingham H.O.U.S.E) to study whether proposed thermochemical materials can cover relative heating load and be power by solar panel in terms of roof size. Meanwhile, PCMs have been used to give a long duration for temperature-controlled chamber in laboratory, and thermochemical materials have been utilized in closed pumping pipe system for cooling and heating purpose. Secondly, characteristic experiments have been conducted on a modified solar collector working with an enhanced PCM tank that is integrated with a fan coil heat exchanger. The results show that light radiation of tungsten lamps (as a solar simulator) has approximately 70% efficiency to equate to solar radiation under the same Pyranometer reading value. At the same time, the solar system can supply over 50°C heating energy and the PCM tank within it can supply higher output temperature with longer duration than water tank. The efficiency of the whole solar collector heating system is over 50% as a heat absorption chamber in sunny days, while only approximately 10% under mostly cloudy weather. Lastly, proposed thermochemical materials (silica gel, calcium chloride, zeolite 13x, vermiculite and activated carbon) have been evaluated on designed thermochemical absorption chamber to supply fresh high temperature air for space heating. The results show that zeolite holds the highest reacted temperature (over 58°C) and vermiculite has really fast absorbing hydration duration, less than half hour. Silica gel possesses the biggest water absorbing capacity and vermiculite has a worse result. A comparison between experimental and numerical modelling results has been revealed. Considering the complexity of processes in cooling and heating system, the agreement of simulation and experimentation is satisfactory, thus the lumped numerical model is acceptable and significant for investigation of this scaled seasonal high capacity heat storage system. A full size seasonal heat storage system with a nominal heating capacity of 3kW has been proposed and illustrated in economic and environmental issues section. The results from net present value (NPV) and internal rate of return (IRR) sensitivity analysis both shows it is greatly attractive to develop this novel system for application in both household and commercial buildings in consideration of its about 9 years payback period, 20 years life span and zero gas (C02) emissions. An intelligent transpired solar collector system is also introduced and illustrated as future work.

Shading louvres on buildings must serve to allow maximum window insolation in winter, while have the prime function of intercepting unwanted direct solar radiation in summer; which could cause excessive solar heat gain, especially in glazed offices and commercial spaces. Studies of the effect of solar protection on heating and cooling loads show that shading strategies are climate dependent. And it is accepted today that solar protection does reduce energy use for cooling, and tends to increase heating loads. The balance between the benefits in cooling and the losses in heating is only achievable by good designs. The main focus of this research work has been in harnessing the thermal energy available within the incident solar radiation intercepted by the shading louvres; hence benefiting, from shading in terms of energy savings, as well as from the collected energy. In achieving this aim, both theoretical and experimental techniques have been utilized, as design analysis tools, in order to select a design that satisfies both the efficiency and cost criteria. A suitable collector design has, then, been identified, its thermal performance characterised, and its prototype manufactured and built. The prototype of the chosen design has been field-tested in Nottingham-England and Porto-Portugal. Finally, the characteristics of the design have been incorporated into a computer simulation scenario, in which a real office building in Winterthur-Switzerland has been analysed for its total (cooling and heating) annual energy consumption. Findings of this research work indicate that these louvres, despite certain geometrical limitations, could act as solar collectors with good energy collection characteristics. And they could contribute with substantial reductions in the overall annual energy consumption resulting from the combined effect of shading and collecting energy. This was found particularly to be the case when the collected energy is made to part-fuel, an adsorption chiller for the purpose of air-conditioning the same building.

Renewable energies are a critical element for reducing greenhouse gases emissions and achieving a sustainable development. Until recently, building integration of renewable sources was focused on solar technologies. Nevertheless,building integrated wind turbines can and must be part of the solution to the global energy challenge. This research investigated the potential of integrating small vertical wind turbines between medium-rise buildings. Wind velocities were measured around 7 fifteenstorey towers. The measurements were carried out for nine different configurations,using a boundary layer wind tunnel and computational fluid dynamics (CFD) simulations. Computed and measured results showed reasonable agreement. The differences were more apparent at ground level. It was established that building orientation and the separation between buildings defines to a great extent the wind environment around buildings. It was found that a distance between buildings of 15 metres and an orientation of θ=260˚ produced the higher augmentation factors. This configuration produced up to 17,812kWh in a typical Nottingham UK year, using six vertical wind turbines of 2.5kW each. Results suggested that the use of CFD as a visualisation tool is extremely useful at design stages in projects involving the integration of wind turbines. Nevertheless, the results of CFD simulations are highly dependent on the type of roughness modification applied to the wall functions, the choice of the turbulence model and the modelling of the inlet wind velocity profile. Because servicing buildings accounts for around half of the UK’s total energy consumption, the need to reduce the consumption of fossil fuels is central to good building design. That is why the architectural practice must respond professionally by delivering buildings that successfully integrate wind energy technologies, which can only be achieved if the designer actively engages with the environmental design principles and improves his understanding of building physics.

Conventionally the power network operators were obliged to buy all the wind energy generated by wind farms. However, as the penetration of wind energy (or generally any other sort of renewable source) in a power system is increased, the ability of other generators to balance the demand becomes limited. This will necessitate the control of wind turbines in order to generate a given demand power rather than extracting the maximum wind power. This control approach is termed “Power Demand Control” in this thesis. In contrast to Power Demand Control, “Power Smoothing Control” utilizes energy storage systems in order to absorb high frequency wind fluctuations, hence, delivering a smoother version of wind power into the grid/load. The drawback of the Power Smoothing approach is that the average power into the grid/load is still determined by the available wind power rather than the system operator. The Power Demand Control approach, which has received little attention in literatures, is the main focus of this thesis. This research proposes control schemes with and without external energy storage for the Power Demand Control strategy. This thesis studies different possible methods of applying Power Demand Control, in particular the droop control method. It is shown that a droop-controlled wind farm does not need a central “Supervisory wind Farm Control” unit to determine the power demanded from each DFIG. Moreover, a droop-controlled wind farm has the advantage of controlling the local grid voltage and frequency. This means that no external voltage and frequency source is required which makes a droop-controlled wind farm a more suitable option for integration of wind energy at distribution level. The classical droop control is modified in order to make the DFIGs share the demand power not only according to their ratings but also to their associated available wind power. The applications of the control paradigm are discussed, including: integration into microgrids, AC grids and HVDC connection feeders. This work mainly concentrates on microgrid applications. An Energy Management System is proposed in order to keep the energy level of the energy storage (or the DFIG’s shaft speed) within its limits using an Auxiliary Generator and a Dispatchable Load. Different possible system configurations are introduced and their advantages and drawbacks are discussed. It is illustrated through simulation that the proposed control scheme can inherently ride-through a grid fault with no need for communication. Furthermore, it is shown that the control scheme can operate if the wind speed drops to zero. The simulations are carried out using the PSCAD/EMTDC software.

This thesis considers historical applications of naturally renewing energy resources in Britain from the beginnings of public electricity supply in the late nineteenth century to the period immediately prior to the first State interest in such technology in the early 1980s when it became conceptualised as 'renewable'. After a comprehensive review of twentieth century engagements with renewable energy and the academic literatures pertaining to 'water, engineering and landscape' the thesis focuses on two distinct case studies. The first charts the technological, cultural and political evolution of hydro-electricity for public supply which developed over the course of the nineteenth century and was instituted from the 1870s. Detailed consideration of the Worcester hydroelectric station reveals that the development of hydro-electricity in the late nineteenth century symbolised a wider social and cultural demand for 'civic improvement’, and highlights the nature of water as a contested resource within late-Victorian civic arenas. The second traces the history of the Centre for Alternative Technology (CAT), a practical demonstration of alternative energy technologies established in rural mid-Wales during the early 1970s. In a discussion centred on 'alternativeness', the exploration of alternative energy technologies in the early 1970s was the preserve of an emerging counter-culture which sought to implement new visions of Environment and Society. Having revealed these hitherto dormant histories, the thesis concludes with a comparative discussion of the two case studies reflecting on these respective renewable energy projects and their uses as instruments of ‘modernisation' and attempts to extract the significance of these histories in the context of current discourses of renewable energy.

The UK has committed to sourcing 15% of its energy from renewable sources by 2020 and wind turbines have the potential to contribute towards this target. Due to the Feed-In-Tariffs introduced by the UK Government in 2010, the potential uptake of micro-generation methods such as small wind is likely to increase. However, many barriers exist which prevent widespread implementation, such as noise concerns. There is little work available in the open literature quantifying the problem because much of the existing research focuses on large scale turbines. The need for an increase in interdisciplinary research in this area has also been called for. This research fills the gap in the literature by seeking to better understand the noise levels generated by small wind systems, the characteristics of the noise and people’s reactions to this noise. The research is interdisciplinary, incorporating engineering, to measure, characterise and model the noise from small wind systems and psychology, to identify the type of people who are most likely to perceive the noise. Environmental noise measurements have been taken at small wind system installations to quantify and characterise the noise levels. This work included an assessment of the attenuation of the noise. Studies have been carried out on individuals living close to small wind system installations, as well as individuals being played recordings of wind turbine noise to investigate the level and type of noise they perceive and to link this to an individual’s attitude towards wind turbines, personality traits and symptom reporting. CFD has been used to model the flow fields around 2D blade sections to identify the likely noise mechanisms associated with small wind systems by observing the turbulent regions near the aerofoil wall. Finally, a comparison of the three methods has been carried out to identify that the overall level of small wind system noise is low but it is the nature of the sounds that increase the likely perception of the noise.

Polymers are essential to modern life. Yet there still remains a wealth of knowledge to discover regarding novel polymeric materials, processing techniques, and applications. The synthesis and application of nanostructured amphiphilic block copolymers have attracted significant interests in the last decade. Depending on the structure, composition, and architecture; a wide range of applications have been reported in various fields of research. The need to accurately access the fundamental structure-property relationships in polymers are of paramount importance to the performance in various applications. Some of these applications include the use of polymer membranes for CO2 capture from flue gas, for water purification and wastewater treatment, as well as polymer electrolytes for lithium batteries. This dissertation therefore, focuses on contributing fundamental knowledge on the structure-property relationships of amphiphilic block copolymer membranes to improve its performance. With the use of poly(styrene–block–ethylene oxide), (SEO) and high molecular weight poly(ethylene oxide) membranes and polystyrenes of various molecular weight and tacticity, experimental work has been conducted with relevant consideration in the aforementioned application areas. The fundamental study of the effects of molecular transport (e.g. water vapor) in an amphiphilic block copolymer membrane consisting of hydrophilic blocks of poly(ethylene oxide) and hydrophobic blocks of polystyrene (PS-b-PEO) was investigated. The influence of water solubility and diffusivity on the block copolymer morphology were examined at various temperatures and water concentrations. A comprehensive study conducted using Fourier-transform infrared spectroscopy (FTIR) to investigate the effect of water activity on PEO crystallinity, and how the PEO crystallinity in turn affects water sorption and diffusion was investigated. Also, isothermal vapor-sorption equilibria and diffusion coefficients of water in different architectures of block copolymer membranes will be discussed. This fundamental study is important for applications that rely on PEO-containing materials, as PEO crystallite melting dramatically impacts transport and mechanical properties. For lithium battery application, the study of ion association effects and the ion-polymer interactions in high molecular weight poly(styrene–ethylene oxide) block copolymer (SEO) and complexes with lithium bis(trifluoromethane sulfonyl) imide salt (LiTFSI) as polymer electrolyte using FTIR-ATR spectroscopy were conducted. The dissolution of the lithium salt in the PEO phase as it influences the structure of the ion conducting phase of the polymer (PEO) was investigated. The infrared bands observed in the polymer–salt complexes as a function of salt concentration and temperature show different solvation and degree of ion association behavior. An understanding of the relationship between ionic conductivity and degree of solvation of lithium salts as a function of ion concentration was explained from the FTIR-ATR results. Also, Structural and stress relaxations have been measured with x-ray photon correlation spectroscopy (XPCS) and rheology, respectively, as a function of salt concentration and temperature. Results from XPCS experiments showed hyperdiffusive motion for various lithium salt concentrations and at varying temperatures, which is indicative of soft glassy materials. This behavior is attributed to cooperative dynamics. The decay time was a weak, non-monotonic function of salt concentration and decreased with increasing temperature, in an Arrhenius fashion. In contrast, the shear modulus decreased with increasing salt concentration and increasing temperature. The entanglement relaxation from rheological measurements followed Vogel-Fulcher-Tammann behavior. The structural decay time was slower than the entanglement relaxation time at temperatures above the glass transition temperature, but they were approximately equal at Tg regardless of salt concentration. This may indicate a fundamental connection between cooperative structural motion and polymer chain motion in this material. / A Dissertation submitted to the Department of Chemical and Biomedical Engineering in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester 2017. / September 22, 2017. / Crystallite Dissolution, SEO electrolyte, SEO Structure, Stress relaxation, Structural relaxation, Water Transport / Includes bibliographical references. / Daniel T. Hallinan, Jr., Professor Directing Dissertation; William S. Oates, University Representative; John C. Telotte, Committee Member; Rufina G. Alamo, Committee Member; Hoyong Chung, Committee Member.

In this study, it is aimed to develop an innovative thermochemical energy storage system through material, reactor and process based investigations for building space heating applications. The developed system could be integrated with solar thermal collectors, photovoltaic panels or heat pumps to store any excess energy in the form of heat for later use. Thereby, it is proposed to address the problem of high operational costs and CO2 emissions released by currently used fossil fuel based heating systems in buildings. The aim of the study has been achieved by investigating and evaluating five of the following aspects: • Investigation of the feasibility of building integrated solar driven THS system under cold and mild climates, • Synthesis, characterization and physical experimentation of novel composite sorption energy storage materials • Development and investigation of a modular laboratory scale sorption reactor that use embedded air diffusers inside the sorbent for improving the energy storage density • Development and investigation of a full- scale modular solar driven THS system • Development and investigation of a heat pump driven sorption storage heater using multi-layer fixed bed sorption reactor These works have been assessed by means of computer simulation, laboratory and field experimental work and have been demonstrated adequately. The key findings from the study confirm the potential of the examined technology. Initially, a comprehensive review on thermal energy storage, with the aim of investigating the latest advancements on THS systems was performed. A comparative analysis on applicability of different heat storage methods for short term and seasonal heat storage under climate conditions in the UK, was also carried out. Results showed that short term heat storage is not a feasible option in the UK due to the very limited solar radiation. For the case of seasonal heat storage, it was found that, each 1 m3 of THS can provide averagely 14% of monthly (October to March) heating demand of a 106 m2 building, whereas LHS and SHS can provide 6% and 2% respectively. Later on, a range of candidate composite sorption materials were synthesized and characterized. Based on the applied characterization techniques, it was found that Vermicuilite-CaCl2 (SIM-3a) has excellent Ed coupled with good EMC and temc with its TGA analysis also suggesting significant mass loss in the working range 30 < T < 140 °C. Physical experimentation of the developed materials in a small scale custom test rig was also performed and in accordance with the characterization results, SIM-3a displayed the best hygrothermal and cyclic performance. These findings suggested that SIM-3a has very good potential for use in an open THS system. Upon completion of the material based studies, a 3kWh laboratory scale novel reactor using perforated pipes embedded inside the heat storage material was developed. The overall energy density of the reactor using SIM-3a was found 290 kWh/m3. Based on the obtained encouraging results, same concept was up scaled to a modular 25 kWh sorption pipe heat storage and similar energy density was achieved. Following the experimental work, theoretical analysis of the THS potential in Mediterranean climate conditions is conducted with a case study of the Island of Cyprus. The analysis results showed that the required heat storage volume to fully compensate heating demand of a domestic building in winter (December to February) is 5.25 m3 whilst the time required for charging the THS material with 8 m2 solar air collectors is slightly more than a month. The economic and environmental analyses results showed that payback period of the solar driven THS is 6 years whilst total CO2 emissions savings over 25 years lifetime is 47.9 tonnes. In order to validate the applicability of THS in Cyprus, a small prototype of integrated sorption pipe-solar concentrator was also developed and tested for room heating. It was found that adsorbent could be regenerated with solar energy during winter day time to be utilized at night for space heating. Study results also showed that sorption pipe with a heat storage volume of 0.017 m3 could meet up to 87% of the daily heat demand of a 12.4 m2 building. In order to validate the performance of the laboratory tested THS material and concept, a real scale (1000 kWh) modular solar driven THS system was developed based on the interpretation of the obtained theoretical, numerical and experimental data in earlier stages of the study. The preliminary testing on the prototype showed that each of four reactors could discharge a total of 248 kWh of thermal energy with an average thermal power of 4.8 kW. Additionally it is found that, in direct solar heating mode, transpired solar collectors used in the system could also generate daily total of 17 kWh thermal energy for the average solar intensity of 0.3 kW/m2. In the final stage of the study, a heat pump driven sorption storage heater was developed and investigated. The developed system performance was assessed with 5 different adsorption materials and under different operating conditions. The study results showed that Sim-3a and Vermiculite–(LiCl-CaCl2) (Sim-3cl) has the best hygrothermal performances and hygro-cyclic efficiencies. According to study results, COPs varies in the range of 1→2 depending on sorption materials properties and system operating conditions.

Renewable energy has the ability to play a dominate role in addressing both rising energy demand and the need for sustainable growth. Various policy measures and incentives have aided its growth in both developed and developing countries. This dissertation analyzes existing policies and financial mechanisms used to encourage renewable energy development through three academic papers. I first propose the carbon revenue bond as a new financing tool to complement the environmental credit markets that exist in developed countries. Stochastic modeling techniques are used to simulate future credit prices and determine bond value. Use of the carbon revenue bond is illustrated through three examples of wind energy projects in the European, Australian and New Jersey markets. In the absence of mature markets in developing countries, I develop the strategic structure matrix as a new framework to explain the various effects of policy measures in order to better shape future policy design. By synthesizing previous literature on how organizations are able to affect the diffusion of a new technology, the strategic structure matrix is able to deepen understanding of how policy can influence renewable energy growth. The explanatory power of the framework is demonstrated through a case study on the different paces of wind power diffusion in five Indian states. Lastly, I evaluate the Clean Development Mechanism as a tool to encourage investment from developed nations for renewable infrastructure in developing countries. I create an agent-based model to simulate investment decisions under different improvements to the program, providing quantitative support for the effectiveness of some improvements over others. In addition to each paper's individual contributions, the findings collectively provide important implications for the future of renewable energy policy and its ability to support continued sustainable growth.