Techno-Economic Analysis of Hybrid Concentrating Solar Power Systems

This thesis presents the outcomes of techno-economic studies of power generation using hybrid Concentrating Solar Power (CSP) systems, in particular, the Hybrid Solar Receiver Combustor (HSRC). The HSRC technology consists of a device that integrates a combustor into a tubular solar cavity receiver to enable a schedulable firm supply of electricity. Two innovative configurations of the HSRC were investigated; one operating with conventional combustion while the other operating with Moderate or Intense Low-oxygen Dilution (MILD) combustion. The HSRC was developed to lower the overall cost of renewable electricity generation by reducing the installed capital cost, fuel consumption and parasitic losses of a conventional hybrid Concentrating Solar Power (CSP) plant. The HSRC technology was also developed to provide a firm supply of electricity with lower emissions relative to current state-of-the-art hybrid CSP systems. The thesis presents an assessment of the HSRC, which was based on operation with conventional combustion, with an analytical model that calculates the heat transfer, mass flow rates and energy into and out of the device. A systematic investigation of the influence of controlling parameters on the performance of the device was undertaken. The performance of the HSRC was analysed with a pseudo-dynamic model that accounts for variations in CSP input using historical solar data from sites in USA and Australia. The thermal efficiency of the HSRC was found to be similar to a conventional system of two stand-alone systems, namely; a solar-only cavity receiver and a conventional natural gas boiler, also termed Solar Gas Hybrid (SGH). Additionally, it was found that the HSRC system benefits from the reduction in start-up and shut-down losses, incurred by a backup boiler, and a decrease in parasitic losses due to the integration of solar and combustion in one device. The HSRC was estimated to reduce the overall Levelised Cost of Electricity (LCOE) by up to 17% relative to the SGH system. The sensitivities to key parameters of the LCOE were also assessed, and the results were found to be highly influenced by the price of the fuel (natural gas). In addition, configurations of the HSRC that enable it to operate in the conditions required for MILD combustion were also identified. This is desirable as the combustion regime is known to offer greater compactness, lower NOx emissions, and potential fuel savings due to higher and more uniform heat transfer relative to current state-of-the-art combustion systems. Operating in this combustion regime resulted in a more compact device and an estimated LCOE reduction of up to 4% relative to the HSRC operating with conventional combustion for the same reference receiver size of 30MWth. This thesis also evaluated the potential to lower the cost of hybrid CSP systems by modularising selected components (e.g. heliostat, tower and receiver) in a CSP plant. It was found that the energy losses in a system of small-sized modules employing molten salt as its heat transfer fluid are dominated by electrical trace heating due to the increased in piping length relative to their larger receiver counterpart. However, this can be reduced by a significant amount using alternative heat transfer fluids with a lower melting point such as sodium. In addition, for modularisation to be cost effective, access to alternative, lower-cost manufacturing methods is required. Specifically, the benefit of standard learning rates is insufficient to lower the LCOE on its own.Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 201

Structural and histological characterization of oviductal magnum and lectin-binding patterns in Gallus domesticus

<p>Abstract</p> <p>Background</p> <p>Although chicken oviduct is a useful model and target tissue for reproductive biology and transgenesis, little is known because of the highly specific hormonal regulation and the lack of fundamental researches, including lectin-binding activities and glycobiology. Because lectin is attached to secreted glycoproteins, we hypothesized that lectin could be bound to secretory egg-white proteins, and played a crucial role in the generation of egg-white protein in the oviduct. Hence, the purpose of this study was to investigate the structural, histological and lectin-binding characteristics of the chicken oviductal magnum from juvenile and adult hens.</p> <p>Methods</p> <p>The oviductal magnums from juvenile and adult hens were prepared for ultrastructural analysis, qRT-PCR and immunostaining. Immunohistochemistry of anti-ovalbumin, anti-ESR1 and anti-PGR, and mRNA expression of egg-white genes and steroid hormone receptor genes were evaluated. Lectin histochemical staining was also conducted in juvenile and adult oviductal magnum tissues.</p> <p>Results</p> <p>The ultrastructural analysis showed that ciliated cells were rarely developed on luminal surface in juvenile magnum, but not tubular gland cells. In adult magnum, two types of epithelium and three types of tubular gland cells were observed. qRT-PCR analysis showed that egg-white genes were highly expressed in adult oviduct compared with the juvenile. However, mRNA expressions of <it>ESR1 </it>and <it>PGR </it>were considerably higher in juvenile oviduct than adult (<it>P </it>< 0.05). The immunohistochemical analysis showed that anti-ovalbumin antibody was detected in adult oviduct not in juvenile, unlikely anti-ESR1 and anti-PGR antibodies that were stained in both oviducts. In histological analysis, Toluidine blue was stained in juvenile and adult oviductal epithelia, and adult tubular glands located in the outer layer of oviductal magnum. In contrast, PAS was positive only in adult oviductal tubular gland. Lectins were selectively bound to oviductal epithelium, stroma, and tubular gland cells. Particularly, lectin-ConA and WGA were bound to electron-dense secretory granules in tubular gland.</p> <p>Conclusions</p> <p>The observation of ultrastructural analysis, mRNA expression, immunohistochemistry and lectin staining showed structural and physiological characterization of juvenile and adult oviductal magnum. Consequently, oviduct study could be helped to <it>in vitro </it>culture of chicken oviductal cells, to develop epithelial or tubular gland cell-specific markers, and to understand female reproductive biology and endocrinology.</p

Analysis of Building Energy Savings Potential for Metal Panel Curtain Wall Building by Reducing Thermal Bridges at Joints Between Panels

AbstractTo achieve national greenhouse gas reduction in the building sector, heating and cooling energy in buildings should be reduced. The government has strengthened regulations on insulation performance for building energy savings. However, the building envelope has various thermal bridges. In particular, a metal panel curtain wall comprises a number of thermal bridges at joints between the panels and the fixing units, thus degrading the overall thermal performance. To reduce building energy, it is necessary to reduce thermal bridges in building envelopes. This study aims to analyze the energy saving potential achieved by reducing thermal bridges. For this, the insulation performance and building energy needs of the existing and alternative metal panel curtain wall were evaluated. The alternative metal panel curtain wall that uses plastic molds at joints between panels and the thermally-broken brackets was suggested to reduce heat loss through thermal bridges. As results, the effective U-value of the alternative metal panel curtain wall was reduced by 72% compared with the existing metal panel curtain wall. In addition, annual heating energy needs of the alternative metal panel curtain wall building was reduced by 26%, and annual total energy needs was reduced by 6% because annual cooling energy needs of it slightly increased compared with the existing metal panel curtain wall. In conclusion, the alternative metal panel curtain wall considerably influenced the savings in building energy needs by reducing thermal bridges