• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 119
  • 12
  • 8
  • 7
  • 6
  • 3
  • 3
  • 3
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 204
  • 204
  • 204
  • 119
  • 44
  • 40
  • 37
  • 36
  • 33
  • 31
  • 30
  • 29
  • 28
  • 28
  • 27
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Analysing the effect of DSM projects at South African cement factories / Johannes Paulus Spangenberg

Spangenberg, Johannes Paulus January 2015 (has links)
In any developing country an increasingly higher demand for electricity supply exists. South Africa experienced load shedding during late 2007 and early 2008 and again in 2014 due to a supply shortfall. New power stations are being built to increase the capacity of the national power grid. However this is a lengthy process. Demand Side Management (DSM) was adopted by Eskom’s Integrated Demand Management (IDM) division. DSM is a short-term solution to stabilise the national grid in South Africa by managing the electricity demand on the consumer’s or client’s side. DSM aims to reduce the electricity consumption with immediate results in the short-term. DSM projects were successfully implemented at nine South African cement factories since 2012. Cement factories are ideal for the implementation of DSM projects for the following reasons: cement factories are energy intensive; have adequate reserve production capacity; sufficient storage capacity and interruptible production schedules. The aim of this study is to analyse the effect of DSM projects at South African cement factories. A detailed understanding of the cement production process is a prerequisite. Therefore a critical review of energy utilisation in the cement industry was conducted. Previous work done in the cement production field is evaluated to identify the possible literature shortfall on DSM projects. A set of five distinctive parameters was derived from the literature survey to quantify the possible effects of DSM projects at cement factories. The parameters are demand reduction and electricity cost; production targets; infrastructure; product quality and sustainability. One cement factory, Factory #1, was selected as a primary case study for the analysis model. Factory #1 was used to determine and quantify the effects of DSM projects at cement factories. A simulation was developed to verify the analysis model outcome. DSM projects were implemented at various factories in South Africa and the results from nine sites were used to validate the aim of this study. The study concluded that most DSM projects at South African cement factories were sustainable. Both the electricity supplier and the factories benefitted from the projects. The funding received from Eskom to implement DSM projects is a short-term initiative. However, sustainability of DSM projects is made possible in the long-term by the substantial electricity cost savings on the client’s or factory’s side. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015
12

The cost-effectiveness of comprehensive system control on a mine compressed air network / Stephanus Nicolaas van der Linde

Van der Linde, Stephanus Nicolaas January 2014 (has links)
Compressed air leakage accounts for up to 42% of electrical energy loss on a typical mine compressed air system. By using underground control valves it is possible to reduce the amount of air leakage. Underground valve control was successfully implemented in a South African mine. The project implementation and achieved results are documented in this study. The implementation of underground control valves initially requires a large capital investment. In this study the electrical and financial savings realised by underground valve control and surface valve control were calculated. The payback periods for each control strategy were determined and compared. It was determined that underground valve control can realise up to 40% higher electrical savings than surface control. Depending on the size of the mine and due to the large initial investment, the payback period for an underground valve control system can be up to six times longer than that of a surface control system. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014
13

Domestic demand response to increase the value of wind power

Hamidi, Vandad January 2009 (has links)
This thesis describes a new method to evaluate the value of wind power combined with domestic demand response. The thesis gives a brief overview of current domestic demand management programmes, and highlights the demand response and its current application. Such technology has conventionally been used for different purposes, such as frequency regulation, and to minimize the spot electricity prices in the market. The aim is to show whether such technology may become useful to make the renewables, and in particular wind power more interesting for investors. An assessment framework based on generation scheduling is developed to quantify the value of wind power. A further important aspect of value of wind power is the impact of intermittency on overall reliability of the system. This necessitates increasing the spinning reserve level which will increase the production cost. The changes in the spinning reserve level has been investigated in this thesis and it has been shown that how different forecasting errors may change the overall value of a windfarm over its lifetime. One of the most important aspects of a system containing demand response, is the availability of demand response. A load modelling package is developed to show the potential for demand response in a real system from domestic sector. With every increasing the concerns with regard to future of generation mix in Britain, this work has proposed over 72 scenarios for the future of generation mix in Britain and the impact of demand response to increase the value of wind power in 2020 has been investigated. The assessment framework is enhanced by showing that how the value of wind power combined with domestic demand response may change by changes in emission price, and cost of demand response. This will show the degree of feasibility of such system in which demand response is treated like a commodity.
14

Impact of Elasticity in Domestic Appliances on Aggregate Residential Power Demands

Srikantha, Pirathayini 27 March 2013 (has links)
Power grids in today's developed societies are designed to meet consumer demands in a highly reliable manner. In order to guarantee reliability to consumers, the grid is required to be sized for infrequently occurring demand peaks. The cost of maintaining generation sources that make up the relatively unused capacity of the grid can be extremely high. In addition to high costs, environmental impacts of these sources are also of great concern. In order to serve highly fluctuating peak demands, energy sources such as coal, gas and bio-gas are commissioned by utilities. These sources have a high carbon footprint. In order to prevent wasting extensive amounts of money in maintaining infrequently used grid capacity and causing an adverse environmental impact, a comprehensive study on how elasticity of domestic appliances can be used to reduce the impact of these issues is made. A thorough analysis of appliances in four distinct regions is presented. Significant reduction of peak demands is shown quantitatively for all of the four regions. Based on these positive results, an elasticity based scheme that takes into account user discomfort is proposed for reducing monetary and environmental issues faced by today's utilities.
15

Impact of Elasticity in Domestic Appliances on Aggregate Residential Power Demands

Srikantha, Pirathayini 27 March 2013 (has links)
Power grids in today's developed societies are designed to meet consumer demands in a highly reliable manner. In order to guarantee reliability to consumers, the grid is required to be sized for infrequently occurring demand peaks. The cost of maintaining generation sources that make up the relatively unused capacity of the grid can be extremely high. In addition to high costs, environmental impacts of these sources are also of great concern. In order to serve highly fluctuating peak demands, energy sources such as coal, gas and bio-gas are commissioned by utilities. These sources have a high carbon footprint. In order to prevent wasting extensive amounts of money in maintaining infrequently used grid capacity and causing an adverse environmental impact, a comprehensive study on how elasticity of domestic appliances can be used to reduce the impact of these issues is made. A thorough analysis of appliances in four distinct regions is presented. Significant reduction of peak demands is shown quantitatively for all of the four regions. Based on these positive results, an elasticity based scheme that takes into account user discomfort is proposed for reducing monetary and environmental issues faced by today's utilities.
16

Climate change and peak demand for electricity : evaluating policies for reducing peak demand under different climate change scenarios /

Anthony, Abigail Walker. January 2009 (has links)
Thesis (Ph.D.) -- University of Rhode Island, 2009. / Typescript. Includes bibliographical references (leaves 215-236).
17

Integrated and synchronised approach to DSM initiatives /

Begemann, Morne. January 2009 (has links)
Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009. / Full text also available online. Scroll down for electronic link.
18

Development of an active load shifting technique for demand side management applications

Majani, Charles Chore January 2011 (has links)
Thesis (MTech (Electrical Engineering))--Cape Peninsula University of Technology, 2011. / Initiatives that are directed towards improving power management by a utility provider have to consider technical feasibility, socio-economic and the environment. Patterns of power consumption world over indicate that demand for electricity has over the years been on the rise due to increase in activities that demand usage of electricity. Such activities include construction and property development, development of industries and infrastructure. These activities have strained the power production, whose development does not match the increase in demand. ESKOM, a government authority mandated to generate, transmit and distribute power in South Africa has seen demand surpassing its generation capacity, hence resorting to load shedding actions. Load shedding imposes inconveniences to the consumers who are completely disconnected from the grid, translating to unpredictable periods of darkness. Utility providers have an option of constructing new peaker plants which lie idle most of the day, to take care of high demand during the peak periods, hence, avoid effecting load shedding actions. Various ways of managing load have been presented in this research. In particular, the research investigated possible ways utilities use in managing their capacity with an aim of developing an alternative method and tool for Demand Side Management applications that can be used by energy utility to improve reliability, manage and control consumption of electrical energy through selective shedding of the load connected to the consumer when the demand surpasses the utility's safe capacity.
19

Inclusion of “value” concepts in evaluation of demand-side management in electric utility planning

Nelson, Sushil Kumar January 1992 (has links)
No description available.
20

Identifying the nature of domestic load profile from a single household electricity consumption measurements

Ihbal, Abdel-Baset M.I., Rajamani, Haile S., Abd-Alhameed, Raed, Jalboub, Mohamed K. 2011 March 1922 (has links)
Yes / Detailed electricity load profile for domestic building is an important requirement for the accurate analysis of demand side management. The use of electrical appliances within domestic buildings varies significantly with respect to time, mainly in accordance with the activity and behaviour of the occupants. This paper presents results from a monitoring study of electrical energy consumption profiles for One UK household (two adults with children). Measurements for whole household electricity consumption have been obtained over a period of ten months. They were all obtained at one minute interval. Monthly energy consumptions, daily and overall profiles were derived for this household type from the monitored data. It is intended that the results presented in this paper can be used in the quest for a precise forecast method for electricity consumption for occupants living in the same type of household in the UK. This will allow greater confidence in the sizing of, e.g., adopting renewable energy sources in this type of household. Further investigation is needed for a large sample of households to improve the understanding of monitoring high resolution domestic energy consumption. / MSCRC

Page generated in 0.1186 seconds