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A solar based integrated system for hydrogen and methanol production is investigated. Energy and exergy analyses of a hydrogen production plant, thermodynamic assessment of methanol synthesis plant, and exergy analysis of the integrated solar based system for hydrogen and methanol production are performed. The analysis of hydrogen production is found to be essential in order to investigate for further design parameters for methanol synthesis procedure. The present analysis shows the effects of temperature and current density on hydrogen production. Thermodynamic parameters of the methanol synthesis plant, such as temperature and pressure, appear to be an important role in methanol production. Based on the methods of physical domain of the system, the optimum temperature of methanol synthesis is obtained for the final design of the methanol plant. It is concluded that increasing pressure improves the methanol synthesis process; however, methanol conversion takes place at 493 K. The energy and exergy efficiencies of the system are reduced by 30% if the electrolyser operates at 300 K. The efficiencies of the system are also highly dependent on the solar intensity. The system efficiencies can be tripled if the intensity of solar radiation is increased to 600 W/m2 instead of 250 W/m2. / UOIT

To carry out the implementation of some type of renewable energy must do a viability study because the weather conditions at all sites are not the same and therefore the profitability of these technologies would not be good. In case of this project, it is taken into account two of the most important technologies which results are very good around of the world. They are photovoltaic and wind power energy. It will be analysed both kind of energy production from how to produce energy with photovoltaic system and with wind power till how much energy is produced by both ways in one year and whether is this ways to produce electricity is profitable in relation of the investment costs, maintenance, etc...

The photovoltaic energy conversion system (PV cells or solar cells) has been researched over the last few decades, and new technologies have been proposed. At the same time, the synthesis of nano-scale materials has been investigated intensively from the 1990s. These new types of materials encourage the development of new PV technologies with extensive research. Dye-sensitized solar cells (DSSCs) can be a part of these efforts. Since first presented in 1991, DSSCs have become the center of attention due to their great advantages to the traditional silicon solar cells. However, it remains a challenge to develop better performing DSSCs since the efficiency of DSSCs is still much lower than that of high performance solar cells. To meet this challenge, the different types of TiO2 nanostructures in DSSCs have been studied. This thesis presents the synthesis of TiO2 hetero-structures. These structures can achieve two important factors in DSSCs. One is the electron pathway for high electron transport rate, and the other is the large surface area for the dye absorption. TiO2 hetero-structures were successfully synthesized by using a simple thermal annealing method. The synthesis method required neither a high reaction temperature nor complicated reaction processes and produced dense TiO2 nanowires and incorporating TiO2 nanoparticles with relatively short reaction time. The key parameters of growing 1-D TiO2 nanostructures were the Cu eutectic catalyst, the reaction temperatures, and the annealing time. The repetition time and the reaction temperatures were important factors for incorporating TiO2 nanoparticles. The structure and composition of as-grown samples were analyzed using an x-ray diffractometer, a scanning electron microscope, a field emission scanning electron microscope, a transmission electron microscope and an ultraviolet-visible spectroscopy. The results showed they were crystalline structures in rutile phase of TiO2. From this research, we can utilize hetero-structures as an electrode of DSSCs. We also expect that our simple and effective synthesis method can be used for growing other kinds of metal oxide nanostructures, especially for those melting temperature are high.

This thesis proposes an implementation of a DSP-Based single-phase small-scale photovoltaic energy conversion system. The conversion system converts dc power generated by photovoltaic cells into ac power. A digital signal processor and a combined circuit with push-pull and full-bridge architectures are used in this study to reduce the complexity of the circuit design. Several operation and protection functions, such as maximum power point tracking, over/under voltage protection, over current protection, over/under frequency protection and detection of islanding operation are considered in the design. The operation performance of the conversion system at different stages is analyzed. The proposed conversion system can supply the local loads and feed excess power to the utility network with unit power factor (grid-connection mode), or it can supply loads exclusively (stand-alone mode). The simulation and experimentation results are presented and discussed to show the performance of the photovoltaic system and verify the feasibility of the proposed energy conversion system.

In the environmental protection issues and natural resources problem to expand and develop ¡§renewable energy resource¡¨ and ¡§green energy resource¡¨ are the trend of global pursued. Many developed countries have given zealous and efforts to active the solar energy plan. The photovoltaic industry has marketed incentive programs. Currently, Use all energy resources to rely on import above 95% on Taiwan. To decrease consuming fossil fuel should be constructive to spread applies of solar energy. This study was the preliminary statement to develop route and trend of worldwide photovoltaic industry in the pass, presently, and in the future. And then to analyze the data of operate results of the new entrant solar cell industries in the Taiwan. By way of competition strategy, competition advantage, an analysis of competition power, diamond model and vertical integration etc., theory. In this study case, the ways that many companies enter the solar cell market are strategy ventures, and vertical integration to increase production. To confer the structure of solar cell industry, finding Niche at a series action of value. To create acceptable value of the customer. And then to provide a solar cell industry model of competition advantage.

Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 79-82). Also available in electronic version. Access restricted to campus users.

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published_or_final_version / Chemistry / Doctoral / Doctor of Philosophy

Solar cells have been traditionally developed for optimizing three key steps for charge carriers: generation, separation, and transport. Conventional solar cells are essentially PN junction based, and utilize the internal electric field near the junction interface for realizing charge carrier separation. However, this kind of structure limits material choices and device fabrication to form a working junction due to issues such as lattice mismatch, doping, and band alignment. Ferroelectric photovoltaic devices with typical capacitor structure have been developed to overcome the junction caused disadvantage but suffer from the poor charge transport issue. In this work, novel ferroelectric-semiconductor photovoltaic devices were developed and investigated in detail with experimental results and theoretical simulation. This type of solar cell is fundamentally different with traditional PN junction based solar cells, utilizing ferroelectric polarization for charge separation in semiconductor layer. Systematical works have been conducted on: (1) device working principle and mechanism study; (2) effect of electrode; (3) influence of device key dimension parameters. The new cells showed the rectifying behavior and effective photovoltaic effect after specific asymmetric polarization. Furthermore, the device performance has been improved through adjusting electrode design and semiconductor layer thickness, which is mainly due to the optimized electric field strength and distribution resulting from polarization. As low cost commercial semiconductor, the multicrystalline silicon (mc-Si) has great potential application in the novel ferroelectric-semiconductor photovoltaic devices. However, the grain boundaries with high density of defects limit the material electric properties. In order to improve the multicrystalline silicon transport property, a polar molecules system was developed to play the role in grain boundaries passivation. The small polar molecule composition and solution passivation process were carried out to optimize the passivation effect. The result showed the developed ZK series solutions reduced the Rsheet across large-angle grain boundaries by up to more than one order to be close to the bulk Rsheet. Also, the correlation between the grain misorientation and passivation effectiveness was built up. / published_or_final_version / Mechanical Engineering / Doctoral / Doctor of Philosophy