6 results on '"Creagh, Chris"'
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2. A simple hourly wind power simulation for the South-West region of Western Australia using MERRA data.
- Author
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Laslett, Dean, Creagh, Chris, and Jennings, Philip
- Subjects
- *
DATABASES , *WIND power , *RENEWABLE energy sources , *TIME series analysis , *AUTOREGRESSIVE models - Abstract
A simple simulator capable of generating synthetic hourly values of wind power was developed for the South West region of Western Australia. The global Modern Era Retrospective Analysis for Research and Applications (MERRA) atmospheric database was used to calibrate the simulation with wind speeds 50 m above ground level. Analysis of the MERRA data indicated that the normalised residual of hourly wind speed had a double exponential distribution. A translated square-root transformation function y n = ( ( 1 . 96 + y e ) − 1 . 4 ) / 0 . 302 was used to convert this to a normal-like distribution so that autoregressive (AR) time series analysis could be used. There was a significant dependency in this time series on the last 3 h m so a third order AR model was used to generate hourly 50 m wind speed residuals. The MERRA daily average 50 m wind speed was found to have a Weibull-like distribution, so a square root conversion was used on the data to obtain a normal distribution. The time series for this distribution was found to have a significant dependency on the values for the last two days, so a second order AR model was also used in the simulation to generate synthetic time series values for the square root of the daily average wind speed. Seasonal, daily, diurnal, and hourly components were added to generate synthetic time series values of total 50 m wind speed. To scale this wind speed to turbine hub height, a time varying wind shear factor model was created and calibrated using measured data at a coastal and an inland site. Standard wind turbine power curves were modified to produce an estimate of wind farm power output from the hub-height wind speed. Comparison with measured grid supervisory control and data acquisition (SCADA) data indicated that the simulation generated conservative power output values. The simulation was compared to two other models: a Weibull distribution model, and an AR model with normally distributed residuals. The statistical fit with the SCADA data was found to be closer than these two models. Spatial correlation using only the MERRA data was found to be higher than the SCADA data, indicating that there is still a further source of variability to be accounted for. Hence the simulation spatial correlation was calibrated to previously reported findings, which were similar to the SCADA data. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
3. Structural Thermal Stability of Graphene Oxide-Doped Copper–Cobalt Oxide Coatings as a Solar Selective Surface.
- Author
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Rahman, M. Mahbubur, Jiang, Zhong-Tao, Yin, Chun-Yang, Chuah, Lee Siang, Lee, Hooi-Ling, Amri, Amun, Goh, Bee-Min, Wood, Barry J., Creagh, Chris, Mondinos, Nicholas, Altarawneh, Mohmmednoor, and Dlugogorski, Bogdan Z.
- Subjects
GRAPHENE oxide ,THIN films ,FOURIER transform infrared spectroscopy ,SYNCHROTRON radiation ,X-ray diffraction ,THERMAL stability - Abstract
3d transition metal oxides based thin film coatings such as copper–cobalt oxides exhibit high absorption in the visible region and low emittance in the infrared to far-infrared region of the solar spectrum which is favourable for use as potential selective surface materials in photothermal devices. These materials have the potential to minimize heating while increasing absorption in the operative spectrum range and therefore achieve higher solar selectivity. A series of mixed copper–cobalt metal spinel oxides (Cu x Co y O z ) doped with graphene oxide thin films were deposited on commercial grade aluminium substrates using a sol-gel dip-coating technique at an annealing temperature of 500 °C in air for 1 h. Characterizations of the synthesized films were carried out by high temperature synchrotron radiation X-ray Diffraction (SR-XRD), UV–Vis, Fourier Transform infrared spectroscopy (FTIR) and X-ray photoelectron microscopy (XPS) techniques. High thermal stability of coatings with multiple phases, binary and ternary metal oxides, was defined through SR-XRD study. FTIR analysis shows moderate (<80%) to high (up to 99%) reflectance in the infrared region while the UV–Vis investigations demonstrate that, in the visible region, solar absorption increases gradually (up to 95%) with the addition of graphene oxide to the Cu x Co y O z coatings. With the incorporation of 1.5 wt.% of graphene oxide to the copper–cobalt oxide coatings, a high solar selectivity of 29.01 (the ratio of the average solar absorptance in visible and the average thermal emittance in infrared to far infrared region; α / ε ) was achieved. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
4. A method for generating synthetic hourly solar radiation data for any location in the south west of Western Australia, in a world wide web page.
- Author
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Laslett, Dean, Creagh, Chris, and Jennings, Philip
- Subjects
- *
SOLAR radiation , *WEBSITES , *PHOTOVOLTAIC power systems , *SOLAR energy , *ALGORITHMS - Abstract
Abstract: An algorithm was developed to generate synthetic hourly cloudiness data for any time of the year at any location in the south west region of Western Australia (WA). To enable the algorithm to be used for simulation of the power output of both tilted photovoltaic and concentrating solar power systems, a metric of cloudiness was defined which modifies the clear sky beam, diffuse and reflected solar transmittance. Seasonally and positionally adjusted values of daily cloudiness were generated by roughly mimicking the geographic pattern of annual rainfall in WA. Rather than longitude and latitude, distance along the coastline and distance inland from the coast were used as the positional coordinates. Hourly cloudiness data was generated from the daily values using a first order autoregression algorithm with time varying mean and standard deviation. Two years of measured hourly horizontal solar irradiance data from a network of 31 weather stations was used to calibrate the algorithm. The algorithm was simple enough to run inside a world wide web page and has the potential to be adapted to other regions with a similar pattern of declining inland rainfall. [Copyright &y& Elsevier]
- Published
- 2014
- Full Text
- View/download PDF
5. A large-scale renewable electricity supply system by 2030: Solar, wind, energy efficiency, storage and inertia for the South West Interconnected System (SWIS) in Western Australia.
- Author
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Laslett, Dean, Carter, Craig, Creagh, Chris, and Jennings, Philip
- Subjects
- *
RENEWABLE energy sources , *ENERGY consumption , *ENERGY storage , *ELECTRIC power , *WATER power - Abstract
An interactive web tool was created to simulate 100% renewable electricity supply scenarios for the South-West Interconnected System (SWIS) in the south-west of Western Australia. The SWIS is isolated from other grids and currently has no available hydropower. Hence it makes a good case study of how supply and demand might be balanced on an hour-by-hour basis and grid stability maintained without the benefit of energy import/export or pumped hydroelectric storage. The tool included regional models for wind and solar power, so that hypothetical power stations were not confined to sites with existing wind farms or solar power stations, or sites with measurements of wind speed and solar radiation. A generic model for solar thermal storage and simple models for energy efficiency, distributed battery storage and power to gas storage were also developed. Due to the urgency of climate change mitigation a rapid construction schedule of completion by 2030, rather than the more common target of 2050, was set. A scenario with high wind generation, and scenarios with varying levels of solar power, wind power, distributed battery storage, energy efficiency improvements and power to gas systems were considered. The battery storage system and PV arrays were configured to provide synthetic inertia to maintain grid stability (with a small loss in capacity for each), and existing synchronous generators were kept spinning with no fuel input, adding a small increase to the electrical load demand. The level of synthetic inertia provided by battery storage was estimated for each scenario. The results indicated that a balanced mix of solar PV, solar thermal, efficiency, and storage were the most feasible to be built on a rapid time scale. The required capacity and build rate of the generation and storage systems would be reduced if energy efficiency improvements were implemented on a more rapid schedule compared to the current global improvement rate. The scenario with very high levels of wind power (∼80% generation) were found to be capable of meeting SWIS reliability criteria if very large amounts of distributed storage or some high capacity seasonal reserve generation system such as power to gas were present. High levels of battery storage capacity and efficiency improvement could be as effective as a power to gas system. It was confirmed that all scenarios provided the same or greater levels of inertia than presently provided by conventional generators. This tool showed that it is possible to examine renewable energy scenarios for regional electricity networks without high computing power. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
6. The Ag M5N45N45 Auger photoelectron coincidence spectra of disordered Ag0.5Pd0.5 alloy
- Author
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Jiang, Zhong-Tao, Thurgate, Stephen M., van Riessen, Grant, Wilkie, Peter, and Creagh, Chris
- Subjects
- *
SILVER coins , *PHOTOELECTRON spectroscopy - Abstract
An effect of disorder broadening (DB) on the Ag M5N45N45 Auger spectra in the random substituted Ag0.5Pd0.5 has been investigated by Auger photoelectron coincidence spectroscopy (APECS). Data were collected for the Ag M5N45N45 Auger line coincident with the Ag 3d5/2 photoelectron line (and its higher and lower binding energy sides). It is shown that the broadening of the Ag M5N45N45 line is directly associated with the presence of disorder broadening of the Ag 3d5/2 photoelectron line. The APECS experiment is used to demonstrate the broadening in a novel way. [Copyright &y& Elsevier]
- Published
- 2003
- Full Text
- View/download PDF
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