OpenUCT :: Browsing by Author "Bennett, Kevin"

Browsing by Author "Bennett, Kevin"

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Open Access
Abnormal combustion - methanol versus gasoline
(1988) Yates, Andrew David Bennett; Bennett, Kevin
The maximum efficiency of conventional gasoline engines is largely determined by the compression ratio, and this is limited by the onset of kno8k. The maximum cylinder size is similarly constrained. The relatively higher knock resistance of methanol opens up possibilities for increased efficiency or engine size. The auto-ignition of methanol and gasoline was characterised in terms of fundamental parameters and the results were compared. The research findings were used in the analysis of a particular combustion chamber design to assess the potential of using squish as a means of avoiding knock in a large, spark-ignition methanol engine.
Open Access
An energy supply and demand model for South Africa
(1981) Silberberg, R B; Dutkiewicz, Ryszard Karol; Bennett, Kevin
Open Access
An analysis of the feasibility of using a solar water heating system in a hotel : a case study
(2010) Fahy, Gary; Bennett, Kevin
The use of solar energy to heat water will not only contribute to the mitigation of global climate change due to the reduced combustion of fossil fuels, but it will also reduce the demand on South Africa's strained electricity supply infrastructure. The hotel industry is particularly energy intensive and the production of hot water makes up a significant portion of its electricity consumption. Furthermore, South Africa boasts one of the world's most abundant solar radiation resources. Thus far, however, the use of large-scale solar water heating (SWH) systems in South African hotels is limited, with the lack of economic feasibility likely to be the core reason.
Open Access
Application of photovoltaic solar energy to medium-scale installations
(2001) Bezuidenhout, Sandra; Dutkiewicz, Ryszard Karol; Bennett, Kevin
Although South Africa has significant energy reserves, some 50-60% of the South African population is without access to electricity. Lack of infrastructure is one of the root courses of which energy supply forms an important component. The energy sector is an integral part of the whole economy, and energy planning requires analysis of the links between the energy sector and the national economy. Local economy can be developed, if energy provision and supporting services are made available to rural areas. South Africa has, so far, developed and implemented energy activities without a solid base in energy policy and macro-economic planning. This has resulted in the situation where energy planning has taken place on a sectoral basis without much regard for socio-economic development objectives or inter-energy considerations.
Open Access
The clean development mechanism potential of a combined heat and power plant in Stellenbosch, South Africa
(2007) Bellingham, Christopher Grant; Bennett, Kevin; Van Es, Denis
Only 50-60% of the roundwood volume harvested by commercial sawmills in South Africa is sold as timber. The rest is sold as timber by-products, utilised as fuel in sawmill boilers, or disposed of as waste res idues. This dissertation assesses the Clean Development Mechanism (CDM) potential of a proposed Combined Heat and Power (CHP) plant that will utilise a sawmill's byproducts, or waste residues, as its fuel source; the sawmill is located in Stellenbosch, South Africa. The sawmill employs standard production techniques as found in large sawmills throughout South Africa, enabling the results of this dissertation to be utilised as a reference for South Africa's total sawmill CHP potential. The CHP plant's emission neutral energy will replace fossil-fuelled energy, thus offsetting Greenhouse Gas (GHG) emissions. The plant will generate revenue from the sale of GHG emission credits, in addition to electricity and other products. The proposed CHP plant has the potential to reduce annually more GHG than any other CDM project currently registered in South Africa. In addition to the environmental benefit, the plant will require labour for its construction and operation, resulting in job creation and skills development.
Metadata only
Development of a least cost energy supply model for the SADC region
(2004) Alfstad, Thomas; Bennett, Kevin
Energy plays a pivotal role in economic growth and improving livelihoods. Although better supply of energy does not automatically guarantee an acceleration of human development, it is a prerequisite for it. It is essential for preparation and conservation of food, for sanitation and for all productive activity. Finding effective means of providing safe, affordable and reliable energy services is therefore of critical importance to governments and organisations endeavouring to promote sustainable development. Energy also places excessive strain on investment capital in developing countries. It is not uncommon for an African country to spend over 30% of its development budget on the energy sector. Limiting the need for capital expenditure in the energy sector could therefore free up resources for other pressing needs. To address these issues, this dissertation develops an energy system model for the SADC region using the TIMES framework. The model is an optimisation tool designed to find least cost energy supply strategies. It has an individual representation of each country in the region, but allows them to trade in energy. This makes it possible to evaluate coordinated strategies and pooling of resources, and thus to identify solutions that benefit the region as a whole. Because of the uneven distribution of energy resources there is significant scope for cost reductions through trade and cooperative efforts, if appropriate strategies are developed. Short country profiles that describe each country's energy sector were compiled from the data available in the public domain and are presented. It was found that energy statistics for the region are generally poor, especially on the demand side, and only available at an aggregated level. Due to data constraints the model does not include a detailed description of the demand side. It targets the electricity supply sector and focuses on the expansion of the regional generation and transmission infrastructure. The analysis is scenario based and examines the impact of changes in economic growth, discount rate and trade policies. The results from the scenarios are distilled into a robust expansion plan that is sufficient to sustain economic growth at a rate equal to that estimated in the short to medium term by the World Bank. The plan is presented in some detail along with the corresponding investment capital requirements. The analysis supports the hypothesis that increased trade can reduce the cost of energy supply in the SADC region.
Open Access
The development of a road profile measuring device with reference to endurance testing of motor vehicles
(1990) Koehler, J F; Bennett, Kevin
This project describes the development of a device to measure the profile of a road. The data describing the roads characteristics are used to compare the qualities of the test tracks at present used by Volkswagen SA (Pty) Ltd for endurance testing of their products, and the Synthetic Road used on their new hydraulic road simulator.
Open Access
Energy efficiency in South African industry
(2003) Fawkes, Howard; Bennett, Kevin
Bibliography: leaves 110-113.
Open Access
An energy supply and demand model for South Africa
(1981) Silberberg, Roger Barry; Dutkiewicz, Ryszard Karol; Bennett, Kevin
The topic of this thesis is the development of a model of energy supply and demand in South Africa to project energy flows up to the year 2005 and also to assess the implications of policy actions. South Africa in the 1980's will be faced by a complex energy planning problem. Politically, socially and economically the country is in a process of significant change, resulting in rapidly increasing overall energy requirements and more selective demand for specific types and grades of energy carrier. Relatively large deposits of coal and uranium exist - providing opportunities for earning foreign exchange now coupled, unfortunately, with the depletion of those resources in the future. Many questions relating to energy, and vital to South Africa, must be resolved in the next few years, particularly concerning the following: - level of coal and uranium exports; - level of energy independence; - domestic synthetic fuels programme; - energy conservation policies; - alternative technology implementation. Energy planning in the past has been inadequate because of its segregated approach in treating each energy carrier, its lack of economic and technological inputs and its inability to highlight sensitive and crucial aspects of the energy sector in the economy.
Open Access
Establishing energy benchmarks for commercial buildings in the City of Cape Town
(2011) Martin, Caroline; Bennett, Kevin
The South African Government has ambitious aspirations relating to energy efficiency in their commercial building stock, but no clear strategy for tackling existing buildings. This research redresses this by examining international approaches to the benchmarking process and applies these in the context of South Africa.
Open Access
Exploring renewable energy powered reverse osmosis desalination plants in South Africa: a costing analysis of Reverse Osmosis desalination plants powered by renewable energy and their potential for South Africa
(2011) Kitley, David; Bennett, Kevin
The desalination process requires large amounts of energy, either in the form of waste heat or grid electricity. If conventional grid electricity sources are used to power desalination plants, the burning of fossil fuels will contribute towards the release of greenhouse gasses.
Open Access
Global review of CSP technologies
(2011) Sikhosana, Qedile; Cowan, Bill; Bennett, Kevin
This global review of concentrating solar power (CSP) technologies is based mainly on an assessment of available international literature, up to 31 October 2011. It includes a review of major CSP projects currently operating or under development at this time; the respective CSP technologies employed; and an assessment of the present and future economics of CSP relative to other conventional and renewable energy electricity-generating technologies. Global outlook scenarios for CSP are discussed, as well as specific conditions and proposals for CSP developments in South Africa. The economic analysis has been limited by several challenges. Since the CSP industry is new, there are few well-documented projects on which to base the analysis. Most of the projects referenced here are from the USA and Spain. As the CSP market rapidly expands, competition in the industry tends to restrict the disclosure of detailed financial/economic information for projects under development. In general, it has been difficult to compare the publicly available economic data, on a reliable basis, since the financial costing parameters used may vary from case to case. In addition, most of the economic forecasts, which have been reviewed, are based on forward modeling rather than practical proven costs. There are uncertainties and quite wide variations in such predictions. This dissertation concludes, however, that there is great optimism for the growing employment of CSP technology in the near future and that CSP electricity-generating costs, in areas with high solar energy resources, are expected to become competitive with levelised electricity generating costs from other conventional and renewable energy technologies. The cost reduction potentials for CSP lie mainly in expected technical research and development advances, and production economies of scale, achieved by high volume deployment, supported by mid-term investment incentives from governments and other agencies. Another cost reduction potential, especially in the South African context, lies in the localization of skills and local fabrication of some plant structures and components.
Open Access
The impact of energy on sustainable economic development in Uganda
(2006) Sebbit, Adam Mohammed; Bennett, Kevin
Energy is a very important resource for national development. Uganda's energy mix comprises mainly biomass, petroleum products and electricity. Biomass is the main source of energy, contributing 92.3%. Petroleum contributes 6.3% and electricity 1.3% of the total energy consumption. The contribution of other forms of energy; wind, solar energy and biogas is negligible. Biomass is mostly used in households and small-scale industries. Petroleum and electricity are used in large-scale industries and in the commercial sector. It was envisaged that this study will be an important input into the National Vision, developed by the Ministry of Finance Planning and Economic Development, for the national development to the year 2025.
Open Access
Implementation plan for the Stellenbosch Wave Energy Converter on the South-West Coast of South Africa
(2014) Frick, Jonathan; Bennett, Kevin; Van Niekerk, W
Lack of experience in wave energy conversion locally leads to uncertainty in the implementation process for the Stellenbosch Wave Energy Converter (SWEC), which is the cause of many developmental hindrances in terms of determining cost estimates, the potential site specific environmental impacts and the required permits. Cost estimates based on assumptions of capacity factor, inflation extrapolated component costs, show that with significant learning rates and reduced risk the SWEC may become cost competitive with current prices of wind and solar energy. The establishment of a full array of SWEC devices carries significant threat to coastal process, marine flora and fauna, ecosystem dynamics and functioning. Mitigation is required to be incorporated into the design and layout of the plant particularly to conserve wave energy to drive coastal processes. A considerable number of permits and permissions are required for the Development of the SWEC, with the National Environmental Management Act forming the base for the majority of permitting procedures. Complexity is added through the coastal leasing policy relying on two different Acts, and policy reform is required to encourage the uptake of wave energy conversion technologies in South Africa as current energy policy acts as a barrier to adoption. Expected environmental impacts are ranked, required permits are listed resulting in the formulation of a simple implementation plan.
Open Access
Investigating different mechanisms for promoting the use of solar water heaters in the Western Cape
(2009) Omer, Mogamat Riyaad; Bennett, Kevin
With increasing carbon emissions and decreasing energy resources, creating sustainable energy sources is crucial. According to the Department of Environmental Affairs and Planning, The Western Cape’s electricity demand forms 31% of the Province’s total energy demand. The objective of this research is to investigate mechanisms for implementing a large-scale Solar Water Heating (SWH) programme, aimed at reducing electricity demand in households, and achieve the renewable energy targets for the Western Cape. The thesis provides an overview of the concepts and technologies around SWH, and their development and application, both globally and in South Africa, with the objectives of identifying barriers to be overcome and methods of incorporating “best practice” into Eskom’s SWH programme. Mechanisms to promote the use of SWH are also considered.
Open Access
Prefeasibility study for a small hydro project
(2010) Culwick, Luel Duncan Lewis; Bennett, Kevin
A prefeasibility study for the production of hydroelectricity on the Kruisvallei 190 farm was conducted. The work progression included a site assessment, preliminary layout design, a basic technical specification, and production and financial analyses.
Open Access
Site location and techno-economic analysis of utility-scale concentrating solar power plants in South Africa
(2011) Brodrick, Joshua JL; Bennett, Kevin
This dissertation comprises a two-part study concerned with the identification and quantification of potential Concentrating Solar Power (CSP) sites in South Africa; and the performance and cost modelling, optimisation and analysis of two CSP technologies in three locations. A further theme of the study is the consideration of the availability of water for plant cooling purposes, and hence the comparison between, and analysis of optimal CSP technologies and cooling methods for each location.
Open Access
A software tool for the preliminary performance modelling of central receivers and associated power cycles
(2011) Smith, Lee; Bennett, Kevin
A software tool for assisting in the preliminary performance modelling of central receiver solar thermal plants was developed using Matlab®. Scope was limited to the thermodynamic study of the power cycle and receiver. The receiver model was validated by comparing results to published data. The model was able to simulate billboard, C-cavity and cylindrical receivers within 1% in cases involving single-phase fluids and by at most 3% - 5% for water. Performance studies were conducted to demonstrate the usefulness of the model. Power cycle studies investigated the performance limits on non-reheated cycles as well as the effects of reheat and regenerative feedwater heating. The results showed expected trends of efficiency increasing with turbine inlet temperature and pressures. Also, efficiency was shown to increase asymptotically with number of feedwater heaters and reheat was shown to improve exhaust quality and efficiency. Billboard and cylindrical receivers were studied in detail using a number of heat transfer fluids, namely thermal oil, molten salt, molten sodium and water to compare the relative performance over a range of rated powers. Water and thermal oil were shown to be the best performing fluids for use in billboards and cylindrical receivers, respectively. Water and salt were shown to require the least area for use in billboards and cylindrical receivers, respectively. The effects of power cycle performance on receiver performance and size were investigated from which it was found that receiver efficiency increases marginally with power cycle efficiency but the required area is reduced significantly.
Open Access
Study into the feasibility and design of a renewable energy portfolio for the Klein Constantia Wine
(2012) Leisegang, Derek Andrew Cecil; Hibberd, Andrew; Bennett, Kevin
The South African wine industry has seen a growing interest in the field of renewable energy in recent years. This has been due, in part, to rising energy costs a long with increased public and consumer awareness around the issues of global warming and sustainability. This project was conceived in the light of these developments, and centres on an investigation into the feasibility and design of a renewable - energy portfolio for the Klein Constantia Wine Estate, located in the Western Cape. A literature survey was undertaken, shedding light on the common uses of energy on wine farms, renewable energy initiatives within the industry and the technologies available. A case study was then conducted using Klein Constanta Wine Estate as the subject. Physical measurements were taken where possible and, along with a combination of topographical, satellite and local climate data , were used to develop estimates f or the energy - generation potential of the farm's renewable resources and the cost implications thereof. Following this, a qualitative and quantitative analysis was conducted to determine the most favourable technologies from a portfolio design perspective. From these findings, three potential portfolio designs were developed, each covering varying degrees of the farm's energy consumption. Based on the se final designs, it was concluded that there was indeed significant potential for investment in renewable energy at Klein Constantia; and that the farm could more than cover its energy requirements. While the financial returns would be minimal, with relatively long payback - periods, the secondary benefits to the farm were considered to be sufficient to justify the investments. The final decision, however, would likely rest on the weight given to the secondary benefits by the farm owners. It was also determined that, in the case of Klein Constantia, the larger the investment the less secure it would be. This was primarily due to the need for higher - risk and more expensive technology options being required when the energy target was raised. With this in mind a renewable energy portfolio, covering only the farm's electricity use, was found to be the most favourable option available to the farm.
Open Access
Techno-economic feasibility of a solar assisted coal power plant
(2014) Govender, Anthony; Bennett, Kevin; Fuls, Wim
The use of solar heat in conventional coal-fired power plants has been demonstrated to reduce the coal consumption of the plant. A reduction in the amount of coal that is burnt by the power plant, means that less greenhouse gases are emitted by the power plant. Hence, the plant has a smaller impact on global warming. Countries such as Australia and the USA have implemented this concept of adding solar heat to a coal-fired power plant. This study investigates if solar heat addition to Duvha Power Station in Mpumalanga, South Africa, is technically and economically feasible. Duvha Power Station is one of the largest coal-fired power stations in Eskom. Two solar heat integration options were examined in this study i.e. the use of solar heat to heat feed water or to produce superheated steam. A market assessment of concentrated solar power (CSP) technologies was performed to establish the maximum water/steam conditions (temperature and pressure) that can be produced by each CSP technology. The CSP technologies assessed were the parabolic trough collector (PTC), the linear Fresnel reflector (LFR) and the central receiver (CR).By using the results of the market assessment, a suitable CSP technology was selected for each integration option. The technical capabilities of each plant area of Duvha Power Station, such as the boiler, turbines, feed water pump etc., was also assessed by reviewing original equipment manufacturer (OEM) data sheets. The solar field size of each integration option was determined through an iterative method, such that none of the technical capabilities of the power station were exceeded once solar heat was added. The annual hourly heat output of each solar field was thereafter predicted by using the System Advisor Model (SAM).The annual hourly heat output of each solar field was then used with a thermodynamic model of Duvha Power Station(referred to as the Duvha Virtual Plant TM model),to calculate the hourly project benefits. The hourly benefits are coal savings, greenhouse gas emission reduction, solar electricity etc. The capital expenditure (CAPEX) and operating expenditure (OPEX) of each integration option was calculated by using cost models provided in SAM. The benefits and costs of each integration option were used in an economic life-cycle assessment (LCA) model, to determine the most economically feasible integration option. It was found that the integration options that produced high-temperature steam have the highest integration effectiveness, such as the steam supply to the high-pressure turbine etc. The LCA revealed that the supply of steam, by using the LFR,to the highest pressure feedwater heater (HPH6), is the most economical option.This is because the LFR technology has the lowest CAPEX and fixed OPEX cost amongst the 3 CSP technologies.This integration option has a discounted payback period of 14,6years and a real Levelised cost of electricity (LCOE) of R1.64/kWhe.

Browsing by Author "Bennett, Kevin"

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