82 research outputs found
Inquiry-oriented learning in physics at Murdoch. In Kirkup, L. (ed) Inquiry-oriented learning in science: Transforming practice through forging new partnerships and perspectives
No full textAt Murdoch University there are two first year physics mechanics units, one is algebra based, co-ordinated by David Parlevliet and the other is calculus based, co-ordinated by Chris Creagh. Both units have between 70 and 120 students in them, most of whom are not physics students. The continual challenge is to engage the non-physics students at an appropriate level while maintaining a high quality unit that extends the physics major students. One way of doing this is to make the units as student focused as possible. This allows students to achieve at a level they are comfortable with
Low-cost Defect Detection of Solar Cells by Electroluminescence Imaging
No full textSolar panels experience a reduction in efficiency as they age due to the variable physical conditions they are exposed to throughout their lifetime, transport and installation. This exposure, due to a combination of effects such as thermal cycling and moisture, can cause a number of defects in the panels, including: cracks in, and non-uniform degradation of, the photoactive material; breakages in the current collectors; and contact finger interruptions (Mansouri 2012, Spertino, Ciocia et al. 2015).
It is therefore of great interest to detect and monitor this degradation process in order to be able to determine with greater precision, the total lifetime of the cells, as the trend of cell cost as a fraction of the module cost declines (Blakers 2015).
Several technologies exist to assess the degradation of solar panel, I-V curves, lock-in-thermography imaging and its derivatives and electroluminescence (EL) imaging. I-V curves are generated by flashing the panel with light and recording the power output that results. Lock-in-thermography looks at the heat generated by the panel and those areas that are defective, such as local short circuits, that dissipate onto the module some of the power generated (Breitenstein, Bauer et al. 2007).
EL works by reversing the role of the panel by putting power through it and making it behave as a light emitting diode instead of a photodiode (Petraglia and Nardone 2011). A typical EL setup is shown in Figure 1.1. The power is supplied by a current source(A) and Norton Resistance (B) to the solar panel (photodiode, C). The camera (D), operates on an independent circuit.
EL imaging, while an effective method of fault detection, is expensive due in part to the camera sensor technologies used, such as thermally stabilised charge coupled devices (CCD) and Indium-Gallium-Arsenide sensors (Petraglia and Nardone 2011, Parlevliet 2016).
This thesis presents a low cost apparatus for EL imaging of standard silicon solar panels and the image post processing techniques necessary to interpret the panel defects
Pulsed PECVD growth of silicon nanowires on various substrates
No full textSilicon nanowires with high aspect ratio were grown using PPECVD and a gold catalyst on a variety of different substrates. The morphology of the nanowires was investigated for a range of crystalline silicon, glass, metal, ITO coated and amorphous silicon coated glass substrates. Deposition of the nanowires was carried out in a parallel plate PECVD chamber modified for PPECVD using a 1kHz square wave to modulate the 13.56MHz RF signal. Samples were analyzed using either a Phillips XL20 SEM of a ZEISS 1555 VP FESEM. The average diameter of the nanowires was found to be independent of the substrate used. The silicon nanowires would grow on all of the substrates tested, however the density varied greatly. It was found that nanowires grew with higher density on the ITO coated glass substrates rather than the uncoated glass substrates. Aligned nanowire growth was observed on polished copper substrates. Of all the substrates trialed, ITO coated aluminosilicate glass proved to be the most effective substrate for the growth of silicon nanowires
Pulsed PECVD for the growth of silicon nanowires
No full textSilicon nanowires of high density and high aspect ratio similar to those shown in the literature (Niu et al., 2004, Hofman et al., 2003) have been grown using a variation of plasma enhanced chemical vapour deposition (PECVD) known as pulsed plasma enhanced chemical vapour deposition (PPECVD) using a range of different modulation frequencies. For the range of frequencies used it was found that the presence of modulated silane plasma increases the average density and sample coverage of silicon nanowires. Both of these effects are proposed as being due to the increase in the number of times the plasma is struck and turned off during the deposition process. For low temperature growth of silicon nanowires the presence of pulsed silane plasma improves the density and sample coverage of silicon nanowires
Clough hazardous area tool
No full textThe need for the adequate management of information has become increasingly prevalent as minimum safety requirements in today’s work place become ever more stringent. This is particularly apparent in the Oil and Gas industry, where the additional presence of flammable gases or liquids is a continual threat to both plant and personnel. Existing management processes are typically manual exercises consuming numerous man hours on-site and in-office. The ability to automate fragments of current information management processes presents an exceptional opportunity to increase efficiency and productivity, ultimately saving time, money and in some instances increasing safety.
Clough Ltd, an Australian engineering, procurement, construction and management contractor whom primarily focus on the Oil and Gas industry, aim to enhance their project delivery capabilities and credibility with the development of the Clough Hazardous Area Tool (CHAT). The CHAT application is intended to provide a level of automation to existing hazardous areas management processes. It is envisioned to be a semi-automatic user centred application that will assist users in various scopes of work by interfacing with existing systems within Clough. This industry thesis is primarily concerned with the high-level planning, scheduling and budgeting of the CHAT project, as well as the detailed design and development of the hazardous area database.
The CHAT database has been designed in the format of a three-tier relational database model and is intended to utilize a serverless computing platform in an effort to reduce operating costs and virtually eliminate the need for server provisions and maintenance. With the use of three data models (user interface, semantic and entity-relationship), 32 normalised tables or data instances have been created to cover the spectrum of HA data and documentation including but not limited to applicable standards and regulations, protection techniques and site equipment.
Unfortunately, the development of the CHAT project, which was intended to incorporate multiple final year computer science thesis students, has been put on hold. Delays are the result of larger than expected project costs, which have not been internally approved within Clough.
Following a series of meetings and presentations with executive committees from Clough and Clough subsidiaries, the Project Team are hopeful approval and funding will be granted in mid- December 2019
Minority carrier lifetime mapping of solar cells
No full textThe minority carrier lifetime distribution across silicon solar cells was investigated using variations of the open circuit voltage decay method. This was performed on monocrystalline, polycrystalline and amorphous silicon solar cells. Light from a white LED was focused using an aperture and a glass bi-convex lens to a spot size of 2mm on the surface of each cell investigated and moved in 1mm increments. At each point, a short pulse of light was emitted from the LED, with the open circuit voltage generated measured with time. This decay was then analysed using two calculation methods using a program written in LabVIEW. The generated minority carrier lifetime values at each point were exported in an array and plotted in Microsoft Excel, so that maps of the minority carrier lifetime were created.
The calculation method from Mahan et al. (Mahan et al. 1979), produced values of the minority carrier lifetime that were consistently lower than the results found using the method from Ranjan, Solanki and Lal (Ranjan, Solanki, and Lal 2008). The values of the minority carrier lifetime obtained in both instances were generally in the expected range, once abnormally high lifetimes found to be a result of external factors (such as increased background effects due to low LED intensities or measured open circuit voltages) were removed.
Due to the high levels of inaccuracy involved in analysis of the open circuit voltage decay curves, it was determined that this method could not produce reliable values of the minority carrier lifetime. However, through agreement of the two calculation methods used, the distribution of the minority carrier lifetime (such as regions of comparatively high and low lifetimes across a cell) could be determined with some accuracy in the case of the monocrystalline and polycrystalline silicon cells
Design, build and test of solar thermal air heating system with application
No full textThe adverse effects on the environment that are associated with the use of fossil fuels has promoted the research and adoption of alternative fuels such as wind and solar. The high costs associated with the purchase of fossil fuels have been another factor that has led to increased use of solar energy in the past decade. This project aims to design and build solar thermal air heating system for education purpose to teach engineering students as well as for researchers at Murdoch University. This will help to create a greater understanding of the different aspects of the solar air-heating system operation.
A mathematical model was created in excel spreadsheets so that the solar air-heating system could be tested so as get an idea of what the actual system would produce regarding maximum temperature and energy. From the results that were generated, it was observed that the maximum temperature varied depending on the period of the year. It was also observed that changing the configurations of the system resulted in different outlet temperatures. For example inclusion of the recycle effect in collector led to a significant increase in the outlet temperature of the collector; the temperature increased from 290C to 370C. Incorporation of the recycle effect in the oven resulted in even higher temperature gains, with the temperature rising to 51%. The percentage of the recycle effect was also observed to affect the outlet temperature, increasing the recycle percentage from 30% to 50% led to higher temperatures in all the tested cases
Performance evaluation of Perth PV systems
No full textThis paper focuses on the performance of the 56kWp PV installation of the north facing elevation of the library at the South Street campus of Murdoch University. This installation was the first step in Murdoch University’s goal to becoming the first privately owned solar power station and the largest PV installation in Perth, Western Australia [1]. In order to perform this analysis, it has been essential to gather output data for the installation from the data acquisition program, which operates around the clock recording this data from the array inverters. A crucial step was to collect weather and meteorological data from sources on the Murdoch campus, this data was used in the performance analysis in order to calculate system loss, efficiency and overall system performance.
This analysis was performed in order to gain a better understanding of the subject matter of solar generation. There are still aspects of large scale solar power generation which are yet to be studied more extensively. This report is centred around the 56kWp solar generator located at Murdoch University’s South Street campus, to enable to University to gain a better understanding of the total power being produced from the system. It is also important to recognise where there is room for improvement in design and application through the study into areas such as soiling, shading and general performance characteristics. This report will allow the University to make an educated and informed decision on any future upgrades or extensions onto the existing system.
Data acquired from the array was used to show how it performs in many different environmental conditions, through the use of modelling programs such as PVSyst and data graphing programs such as Microsoft Excel. By plotting output power data against temperature, rainfall, time of day and output voltage comparison graphs can be produced that allow readers to visualize and understand exactly how each characteristic affects the performance of PV systems in the Perth metropolitan region.
Through this project the array performance characteristics were evaluated. It was found that the array has an average performance ratio of 0.85 for 2014, and that the array does indeed perform well in the Perth region. It was also found that shading impacts the array in a very noticeable way, this shows up as a noticeable depression on the affected inverters. Following through on a soiling study it was found that the array does indeed suffer from the soiling effect, most notably during long periods of dry weather. Degradation effects were also studied during the project but no evidence of these effects were found, these effects will be more prevalent in a longer period of study.
These findings are significant because it allows for a comparison with other arrays in the Perth demographic, the typical array performance ratios in the Perth region is approximately 0.8 [2] [3], from this it can be concluded that the Murdoch array performs better than expected for the region. Shading impacts PV generation and this is evident in the array data. It can also lead to more significant issues such as hot spots and module damage and this can become a costly problem. Soiling has been proven in this scenario to reduce the overall performance of the array, this has been shown through a slow reduction in performance over a long dry period then an increase after a period of heavy rain. Degradation is the biggest issue affecting PV arrays around the world, the cells in the modules experience an aging effect and see a reduction in performance. The Murdoch array has not yet shown signs of degradation in the analysis period of this report of five years, this is indicative of the quality of the installation and the cell manufacturing quality
A revision of IEC 60891 2nd Edition 2009-12: Data correction procedures 1 and 2 PV module performance at Murdoch University
No full textThe focus of this project is to review and effectively assess the first two photovoltaic module electrical performance data correction procedures contained in the international engineering standard IEC 60891: “Photovoltaic Devices- Procedures for temperature and irradiance corrections to measured I-V characteristics.” The formulated workings of the project were used to assess the effectiveness of the correction methods in translating electrical performance data for determining the degradation or performance of photovoltaic modules.
A preliminary literature review of concepts involved in the implementation of project procedures was conducted, so that appropriate experimental testing conditions could be formulated. This project covers information regarding factors that may affect photovoltaic module performance variation and degradation.
Over a period of months in autumn/winter, outdoor field electrical performance data for different PV module technologies at the Murdoch University location was recorded and processed. The data collected was obtained under varying atmospheric conditions, with the tilts and orientations of the modules altered to change the total amount and nature of solar irradiation reaching the modules.
The algebraic equations of the first and second standard correction procedures utilised parameters with values that could be measured directly from the outdoor testing of modules, or deduced from electrical performance data obtained from testing modules indoors at known values of irradiance, temperature and atmospheric spectra.
Indoor performance data simulated with solar irradiance levels and cell temperatures recognised as those matching international standard test conditions, was obtained for use in effectively implementing the correction procedures. The data was also independently analysed and compared.
Outdoor module test performance data was corrected with both correction procedures and collated for analysis. The results highlighted the effects of and correlations between factors that influence module I-V curve dynamics.
When implemented for data translation, “correction procedure one” was found to produce a range of maximum power mismatch accuracy levels from 0.09 to 22.97% with an average accuracy mismatch level of 9.54%. “Correction procedure two” was found to produce a range of accuracy maximum power mismatch levels of 0.19 to 28.64%, with an average accuracy mismatch level of 8.58%.
An assessment of the correction procedures showed that they could be effectively used to gauge module degradation or for comparison of module performance against factory specifications. Both methods showed similar variations in accuracy, with “correction procedure 2” being better suited to situations where the irradiance level difference between two data sets is more than 20%. “Correction procedure 2” has more working parameters and takes more time to establish for correct implementation
Effect of PCM in improving the thermal cooling comfort in buildings ceiling
No full textThe demand for energy increases around Australia because of the massive growth in population and industrial sector, which lead to Increase energy supply. A result of this growth, Increase in the consumption of fossil fuel and that produce more CO2 emission. Many scientist and engineers claimed. Phase change material (PCM) considered a great option in the residential building to save energy and thermal comfort. From this concept, the thesis purposes are to analyse and investigate PCM performance in passive cooling in the residential ceiling by modelling, and experiment methods whether PCM will save cost and reduce CO2 emission.
The method was divided into two parts the first one in modelling and the second part is experimenting. The first part was by modelling the PCM with other types of insulations in the ceiling with the consideration of weather data history around Murdoch University location and the measurement of the whole ceiling design. OPAQUE 3.0 beta software has been used to calculate all of heat gain, heat loss, and an energy reduction of the system in summer and winter. The second part was the experiment and analysed the effect of PCM in the small-scale build that symbolises house with the ceiling. Three-way valve and 5v fans used to control airflow within the ceiling in three different operation conditions Ventilation, Recycling, and Shutdown. Lab View and Arduino software were used to control the airflow and operation conditions by setting the upper limit temperature and the lower limit temperature of the human comfort zone.
The outcome from modelling and simulation of the PCM shows an annual energy reduction between (13% - 21%) and CO2 equivalent emission reduced from 70 Kg to (60.9 Kg to 55.3 Kg). Furthermore, the experiment results indicate a temperature increase inside the build of 3 degrees Celsius as an effect known as greenhouse effect. Both results from simulation, experiment are close, and there was a minor difference in result. Weather was the main factor of not to cover the full potential of the PCM because the experiment done in June. PCM shows promising future in energy reduction and decrees CO2 emission
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