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No description available.

No description available.

No description available.

The basic resource of all solar systems is the sun, and a knowledge of the quantity of the energy available is of prime importance. Although the solar radiation outside the atmosphere is known and almost constant, various climatic factors cause wide variations in its value on the earth's surface. In addition, the relative position of the sun with respect to local points of interest will allow surfaces with different orientations and tracking ability to receive different quantities of solar energy. This research focuses on the effect of cloud cover on the solar radiation received on the earth's surface and presents computer models that calculate its value for the best system configuration. Then a complete assessment of the electrical output of such a system is given. With this purpose in mind, two solar resource evaluation models have been developed; the first method is based on a direct statistical approach correlating clear sky total daily radiation with measured daily insolation. This approach has been applied to a few selected sites and offers the procedure for extending the same coefficients to other sites with similar weather patterns. This model has been tested for six sites in Bangladesh . These sites are located around a "reference" site . The predictions made have shown to be quite accurate. The second model uses an analytical approach that combines clear sky methods with "correction" factors which are based on long term recorded solar ra- diation. In addition, this model has been enhanced by an algorithm that selects the optimal surface orientation that maximizes solar output. Finally, the hourly electrical output of the photovoltaic system is calculated after accounting for the various losses. This is presented as part of a complete solar energy evaluation model. / M.S.

Master of Science in Engineering (Electrical) University of the Witwatersrand July, 2016 / This dissertation uses historical electrical consumption/load and actual solar radiation data to design a solar array for the University of the Witwatersrand’s West Campus. The array must meet the campus’s minimum demand as selling excess generated power back to the utility is not possible at this stage. The financial and spatial impact of adjusting the size of the array, design losses and cloud cover are also investigated. In addition to this, the influence on the payback period of financial variables such as taxes, electricity and start-up costs are also explored. The solar array system design process starts by determining the amount of power that the array must produce or supplement. Thereafter, load estimates and electrical consumption figures that are provided by utility bills or measured with load monitoring equipment are analysed. Furthermore, system losses are factored in which ultimately increases the size of the array. Once all the input variables are analysed, the amount of available solar radiation in the area where the array will be installed is required to determine the amount of energy that the array can produce. Several free databases with this information are available but it is found that this data over predicts the availability of solar radiation. The University has been monitoring the electrical consumption of West Campus since 2012 and solar radiation data is also available for this site. Comparing the satellite derived and measured datasets found that the ground monitored data is 25 % more accurate and therefore better suited for designing a solar array. Individually adjusting the design and financial variables changes the payback period between 3 – 17 %. Combining all the variables can reduce the payback of option 1 from 9.6 years to 6.1 years. Clear legislation needs to be developed for the uptake of renewable energy resources and supported by better rebates for renewable users and harsher taxes for non-renewable users. Should legislation change and if additional capital is available, a larger array will benefit the University more and should be installed as the difference between payback periods is not significant. This is mainly due to decreased costs associated with a higher yield. The financial benefits of a larger array will also be more lucrative if better rebates are enforced. / MT2017

We study timing effects of carbon mitigation and solar radiation management (SRM) policies for correlated pollutants, CO₂ and SO₂. We show that national levels of carbon and sulfur emissions quotas and SRM implementation are positively correlated with each other. First-mover advantages exist when deciding both carbon quotas and SRM levels. Moreover, we use an example to illustrate that if international equity is considered, governments would be willing to choose SRM levels before carbon quotas since it yields higher payoffs and less acid rain and droughts damages. This timing was neglected by all previous theoretical economic models on geoengineering.

This work comprises a radiometric study of Durban‟s solar resource, utilizing data from the Howard College campus of the University of KwaZulu-Natal (UKZN), and the Solar Thermal Applications Research Laboratory (STARlab) at Mangosuthu University of Technology (MUT), located 17 km away. The study has three aims: first to establish a solar radiometric monitoring network for the greater Durban area, comprising the UKZN Howard College and Westville stations, and the STARlab facility at MUT. The UKZN Westville station is under refurbishment and should be operational by the end of 2011. Data from this station are not included in the study. The instrumentation and acquisition software in use at Howard College and STARlab are described. The stations record global horizontal irradiance (GHI), direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), measured by an unshaded pyranometer, a normal incidence pyrheliometer and a pyranometer shaded with a stationary band respectively. Second, to test a number of existing radiometric models against measured data gathered at the stations. Radiometric models assist in estimating missing components of radiation at stations that do not measure all three components separately, for reasons of cost. The models investigated included Erbs et al. (1982), Orgill and Hollands (1977), Reindl et al. (1990), Boland et al. (2001), and Skartveit and Olseth (1987) and correction models by Drummond et al. (1956), Le Baron et al. (1990), Batlles et al. (1995), and Muneer and Zhang (2000) to correct the shadow band effect. Third, to compare data from the two operational stations and to investigate potential spatial differences in sun strength arising from micro-climate effects in the greater Durban area. This takes the form of a statistical analysis of the differences in radiometric data recorded simultaneously at the UKZN and STARlab stations. The study found that the recorded difference in GHI over one year was 0.72%, which lies within the instrument measurement accuracy. Therefore no measurable radiometric differences due to microclimate could be detected and, for the period in which data were collected, measurements from Howard College could be used to estimate irradiance patterns for MUT, and vice versa. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2011.

Thesis (Ph. D.)--University of California, San Diego, 2000. / Vita. Includes bibliographical references.

A range of inorganic materials, with structures based on transition metal centred polyhedra linked through simple or polyatomic anions, has been synthesised and fully characterised. These materials were prepared using a variety of synthetic methods, including the direct high temperature, solid state reactions, and hydrothermal techniques in fluoride rich media. The materials produced were structurally characterised by powder (PXD) and single crystal (SXD) X-ray diffraction techniques with further analysis via infrared and UV/visible/near-infrared spectroscopies, thermogravimetric analysis and scanning electron microscopy. Copper (II) phosphates and related materials have potential applications derived from their near-infrared (NIR) radiation absorbing properties. A range of complex copper phosphate phases in the Cu-P-O or A-Cu-P-O systems, where A is a Group 1 or 2 element, has been synthesised and characterised. The intensity and positions of absorptions in the NIR region found for these materials and derived from d-d transitions on copper, are dependent upon the copper ion coordination geometry and the ligand field produced by the surrounding anions. K2CuP2O7 and the phases A3Cu3(PO4)3 (A = Sr, Ca) were all found to absorb strongly in the NIR region. The NIR absorbance spectrum could be modified further by introducing fluoride into the Cu(II) ligand environment and Cu2PO4F was shown to have a very strong, broad NIR absorption spectrum.