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Dive into the research topics where E.E. van Dyk is active.

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Featured researches published by E.E. van Dyk.


Renewable Energy | 2004

Analysis of the effect of parasitic resistances on the performance of photovoltaic modules

E.E. van Dyk; E.L Meyer

Parasitic resistances are detrimental to solar cell performance because they reduce the device power output. In this paper the effects that series- and shunt resistance have on photovoltaic module performance parameters are discussed. Techniques used to measure these resistances are presented and the results show how current–voltage characteristics and module performance are affected. An analysis of the performance degradation of an a-Si module revealed that, apart from the Staebler–Wronski effect, an increase in series resistance contributed to a power loss of 50% after outdoor exposure of 130 kWh/m2. A 29% decrease in shunt resistance of a CuInSe2 module, over the same exposure, translated to a power loss of 6%. This study shows that the effects of shunt and series resistances on module performance are significant and cannot be ignored. These effects must be understood and taken into consideration when employing photovoltaic modules in systems and when analysing performance degradation.


Renewable Energy | 2000

Development of energy model based on total daily irradiation and maximum ambient temperature

E.L Meyer; E.E. van Dyk

To predict the energy produced by photovoltaic modules under certain meteorological conditions, an energy model can be used. Existing energy models need parameters that are not always available. In this study, an energy model based on regression analysis of total daily irradiation and maximum daily ambient temperature is developed. This model is able to predict daily module energy based on these two parameters only. The data used in this study were collected over a 15-month period at the University of Port Elizabeth (UPE), South Africa. The developed model was first compared to two existing energy models using data collected over the month of October 1998. Its validity was then evaluated over the entire 15-month period using seasonal regression coefficients. An application of the model to predict module energy output is illustrated by using data collected at the South African Weather Bureau (SAWB), Port Elizabeth (PE) station. The predicted energy is then compared to the energy measured at UPE. Results obtained show that the developed model is valid and a good predictor of module energy.


Renewable Energy | 2003

Characterization of degradation in thin-film photovoltaic module performance parameters

E.L Meyer; E.E. van Dyk

This paper characterizes and compares the degradation observed in thin-film module performance. Three commercially available thin-film modules comprising a-Si:H, a-Si:H/a-SiGe:H/a-SiGe:H and CuInSe2 technologies were used in this study. After an initial indoor assessment the modules were deployed outdoors and periodically taken down for indoor assessment. Results obtained indicate that the a-Si modules degraded by the classical Staebler–Wronski effect. The CuInSe2 module, though known to have long-term performance stability, also degraded in this study. The CuInSe2 module showed shunting behaviour before outdoor exposure. This shunting behaviour was enhanced when the module was deployed outdoors under open-circuit conditions. A comparison of the modules’ performances outdoors indicates that the low bandgap CuInSe2 material performs best at high air mass values. This paper emphasizes the importance of being able to analyze module degradation.


photovoltaic specialists conference | 2002

Investigation on the I-V characteristics of a high concentration, photovoltaic array

F.J. Vorster; E.E. van Dyk; A.W.R. Leitch

The aim of this study was to highlight the effects on the I-V characteristics of concentrator arrays due to mismatch between series-connected high concentration PV modules and between single junction cells within a module. The mismatch between cells was caused by a number of factors including: misalignment of optical elements and cells, uneven shading due to dust or delamination of the cell-secondary lens interface, degradation of the main Fresnel lens and non-uniform cell material parameters. Small amounts of mismatch that would go unnoticed at one-Sun insolation levels are vastly amplified at high concentration ratios. This paper reports on, and interprets the regular I-V measurements that were recorded over a period of two years under various conditions. The effect of bypass diodes on the module I-V curves is also investigated. The general characteristics of the measured resultant I-V curves are explained. The degradation of the PV concentrator modules over a period of two years is also confirmed from the I-V measurements.


Review of Scientific Instruments | 2007

High saturation solar light beam induced current scanning of solar cells

F.J. Vorster; E.E. van Dyk

The response of the electrical parameters of photovoltaic cells under concentrated solar irradiance has been the subject of many studies performed in recent times. The high saturation conditions typically found in solar cells that are subjected to highly concentrated solar radiation may cause electrically active cell features to behave differently than under monochromatic laser illumination, normally used in light beam induced current (LBIC) investigations. A high concentration solar LBIC (S-LBIC) measurement system has been developed to perform localized cell characterization. The responses of silicon solar cells that were measured qualitatively include externally biased induced cell current at specific cell voltages, I(V), open circuit voltage, V(oc), and the average rate of change of the cell bias with the induced current, DeltaV/DeltaI(V), close to the zero bias region. These images show the relative scale of the parameters of a cell up to the penetration depth of the solar beam and can be obtained with relative ease, qualifying important electrical response features of the solar cell. The S-LBIC maps were also compared with maps that were similarly obtained using a high intensity He-Ne laser beam probe. This article reports on the techniques employed and initial results obtained.


photovoltaic specialists conference | 2002

Monitoring current-voltage characteristics of photovoltaic modules

E.E. van Dyk; A.R. Gxasheka; Edson L. Meyer

The aim of the study was to build a system to monitor the current-voltage (I-V) characteristics of photovoltaic (PV) modules subjected to outdoor conditions at the University of Port Elizabeth, South Africa. The monitoring of I-V characteristics, module temperature, ambient temperature, and irradiance will enable an analysis of module performance, degradation and or failure. In this paper the design of a low-cost system built to sequentially measure I-V characteristics of seven modules at regular intervals is discussed and an analysis of data obtained is presented.


photovoltaic specialists conference | 1997

Analysis of photovoltaic module energy output under operating conditions in South Africa

E.E. van Dyk; Edson L. Meyer; B.J. Scott; D.A. O'Connor; J.B. Wessels

South Africa does not have any industry standard methodology to evaluate photovoltaic (PV) modules for energy production. The aim of this study is to characterize the energy production of PV modules deployed outdoors at the University of Port Elizabeth (UPE), Summerstrand, South Africa, with the view of facilitating such a standard. The system developed for this study was designed to monitor the energy production of seven PV modules under normal operating conditions. An analysis of energy production of three of the PV modules under test, while operating under prevailing outdoor conditions, is given. Measured energy output is also compared with that predicted using an energy model.


photovoltaic specialists conference | 2000

Analysis of point focussing, high concentration, photovoltaic array

F.J. Vorster; E.E. van Dyk; A.W.R. Leitch

The gains achieved by concentrating the suns rays may be offset if several design factors are not carefully considered. A commercially available 300-sun PV concentrator array was installed at the Physics Department of the University of Port Elizabeth and was evaluated over a two-year period. The high concentration ratios amplify the effects of poor design. This article presents some important results that illustrate how certain design factors impact on the performance of the concentrator array under typical South African conditions.


photovoltaic specialists conference | 2002

Testing of photovoltaic concentrator modules

E.E. van Dyk; F.J. Vorster; A.W.R. Leitch

The aim of the study was to evaluate the performance of point focused, high concentration photovoltaic (PV) concentrator modules, rather than to conduct a qualification procedure. This was done to determine what the actual performance of the modules was under operating conditions, i.e., to answer the question, what power can these modules deliver and how reliable is the system? This paper reports on the evaluation conducted on a PV concentrator system deployed at the University of Port Elizabeth. The types of tests conducted are discussed and significant results shown.


Physica Status Solidi (a) | 2002

High Quality InxGa1—xAs Epitaxial Layers Grown on GaAs by MOVPE

E.E. van Dyk; A.W.R. Leitch; J.H. Neethling

Lattice-mismatched In x Ga 1-x As epilayers grown on GaAs by metalorganic vapour phase epitaxy (MOVPE) were characterised with respect to indium composition and material quality for indium compositions x < 0.14. Photoluminescence spectra, transmission electron microscopy and optical birefringence microscopy were used to study the epilayer quality and In x Ga 1-x As/GaAs heteroin-terface. The photoluminescence spectra exhibit well-defined peaks with line-widths of the bound exciton peaks as low as 4.4 meV, indicative of good quality In x Ga 1-x As epitaxial material. The microscopy showed that the majority of the dislocations are confined to the interfacial region.

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F.J. Vorster

Nelson Mandela Metropolitan University

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A.R. Gxasheka

University of Port Elizabeth

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A.W.R. Leitch

University of Port Elizabeth

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C. Radue

Nelson Mandela Metropolitan University

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M.K. Munji

Nelson Mandela Metropolitan University

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E.L Meyer

University of Port Elizabeth

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W. Okullo

Nelson Mandela Metropolitan University

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E.L. Meyer

Nelson Mandela Metropolitan University

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