MIng (Electrical and Electronic Engineering), North-West University, Potchefstroom Campus, 2015 / Demand side management (DSM) initiatives have been introduced by Eskom to reduce the deficit between the electricity generation capacity and the electricity usage within the country. DSM projects enable Eskom to reduce electricity demand instead of increasing generation capacity. DSM projects are more economical and can be implemented much faster than constructing a new power station. One particular industry where DSM projects can be implemented is on mines. Mines consume about 14.5% of South Africa’s electricity. Producing compressed air, in particular, is one of the largest electricity users on mines. It consumes 17% of the electricity used on mines. The opportunity, therefore, arises to implement DSM projects on the compressed air system of mines. Not only do these projects reduce Eskom’s high electricity demand, but they also induce financial and energy savings for the mine itself. However, during the implementation of a compressed air energy savings project, various challenges arise. These include, among others, operational changes, control limitations, industrial actions and installation delays. All of these can lead to a project not being delivered on time, within budget or with quality results. The purpose of this study is to investigate and address various problems that occur during the implementation of such a compressed air energy savings project. The study shows that although these problems have an impact on the results achievable with the project, significant savings are still possible. Project savings are achieved by reducing the amount of compressed air that is supplied, thereby delivering sufficient compressed air while minimising the amount of compressed air being wasted. During this study, a gold mine’s compressed air network was optimised. The optimisation resulted in an evening peak-clip saving of 2.61 MW. This saving was achieved daily between 18:00 and 20:00 when Eskom’s electricity demand was at its highest. It is equivalent to an annual cost saving of R1.46 million based on Eskom’s 2014/2015 tariffs. When savings from all periods throughout the day are taken into account, the project will produce an annual cost saving of R1.91 million.

MIng (Electrical and Electronic Engineering), North-West University, Potchefstroom Campus, 2015 / Demand side management (DSM) initiatives have been introduced by Eskom to reduce the deficit between the electricity generation capacity and the electricity usage within the country. DSM projects enable Eskom to reduce electricity demand instead of increasing generation capacity. DSM projects are more economical and can be implemented much faster than constructing a new power station. One particular industry where DSM projects can be implemented is on mines. Mines consume about 14.5% of South Africa’s electricity. Producing compressed air, in particular, is one of the largest electricity users on mines. It consumes 17% of the electricity used on mines. The opportunity, therefore, arises to implement DSM projects on the compressed air system of mines. Not only do these projects reduce Eskom’s high electricity demand, but they also induce financial and energy savings for the mine itself. However, during the implementation of a compressed air energy savings project, various challenges arise. These include, among others, operational changes, control limitations, industrial actions and installation delays. All of these can lead to a project not being delivered on time, within budget or with quality results. The purpose of this study is to investigate and address various problems that occur during the implementation of such a compressed air energy savings project. The study shows that although these problems have an impact on the results achievable with the project, significant savings are still possible. Project savings are achieved by reducing the amount of compressed air that is supplied, thereby delivering sufficient compressed air while minimising the amount of compressed air being wasted. During this study, a gold mine’s compressed air network was optimised. The optimisation resulted in an evening peak-clip saving of 2.61 MW. This saving was achieved daily between 18:00 and 20:00 when Eskom’s electricity demand was at its highest. It is equivalent to an annual cost saving of R1.46 million based on Eskom’s 2014/2015 tariffs. When savings from all periods throughout the day are taken into account, the project will produce an annual cost saving of R1.91 million.

Demand Side Management (DSM) is one of the most viable and sustainable short term methods to address the shortfall in electricity generation in South Africa. This is because DSM projects can be implemented relatively quickly and inexpensively when compared with alternative generation options. This specifically applies to the mining industry. South African mines presently consume 15% of Eskom-generated electricity. Mine compressed air systems are some of the biggest users, consuming approximately 21% of mine electricity consumption. Electricity savings on compressed air systems are therefore important. With this study, various Energy Efficiency methods on compressed air systems were investigated. These methods include variable speed drives on compressor motors, temperature control of compressor discharge, minimising pressure drops in the air distribution systems, eliminating compressed air leaks, and optimising compressor selection and control. The most efficient strategies were identified, taking into account factors such as financial viability, sustainability, and ease of implementation. The best strategies were found to be the optimised control and selection of compressors, minimising compressed air leaks, and the optimal control of system pressure. These strategies were implemented and tested on large compressed air systems in gold and platinum mines. Savings of between 10% and 35% on the maximum demand of the systems were achieved. In present monetary terms this translates to as much as R108 million savings for the mines per year at the end of 2009 tariffs. If total mine compressed air electricity consumption can reduce by 30%, it will result in nearly a 1% reduction in total Eskom demand. This shows that mine compressed air savings can make a significant contribution to the drive for Energy Efficiency in South Africa. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2010.

Demand Side Management (DSM) is one of the most viable and sustainable short term methods to address the shortfall in electricity generation in South Africa. This is because DSM projects can be implemented relatively quickly and inexpensively when compared with alternative generation options. This specifically applies to the mining industry. South African mines presently consume 15% of Eskom-generated electricity. Mine compressed air systems are some of the biggest users, consuming approximately 21% of mine electricity consumption. Electricity savings on compressed air systems are therefore important. With this study, various Energy Efficiency methods on compressed air systems were investigated. These methods include variable speed drives on compressor motors, temperature control of compressor discharge, minimising pressure drops in the air distribution systems, eliminating compressed air leaks, and optimising compressor selection and control. The most efficient strategies were identified, taking into account factors such as financial viability, sustainability, and ease of implementation. The best strategies were found to be the optimised control and selection of compressors, minimising compressed air leaks, and the optimal control of system pressure. These strategies were implemented and tested on large compressed air systems in gold and platinum mines. Savings of between 10% and 35% on the maximum demand of the systems were achieved. In present monetary terms this translates to as much as R108 million savings for the mines per year at the end of 2009 tariffs. If total mine compressed air electricity consumption can reduce by 30%, it will result in nearly a 1% reduction in total Eskom demand. This shows that mine compressed air savings can make a significant contribution to the drive for Energy Efficiency in South Africa. / Thesis (M.Ing. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2010.

Energy consumption is one of the major concerns in the current environment, not only because of the limited availability of non-renewable fuels, but also due to the high cost and the pollution generated by energy production. In general, industries consume large quantities of electricity, fuels and other types of energy. Among the industries, the chemical industry is one of the highest energy consumers because of the nature of its processes. This fact makes the chemical industry one of the best candidates for the study and evaluation of different technologies to improve the efficiency of the energy use without affecting the productivity and quality of their processes and products. This thesis analyzes the energy consumption in the chemical industry and provides recommendations to increase the energy efficiency of the critical systems utilized in this industry. Different methods to reduce the energy losses during generation and transmission, the use of waste heat for improving energy efficiency, and several analysis tools to help in evaluating the potential energy and cost savings for each facility are also discussed in this thesis. Several case studies are reviewed to demonstrate the effectiveness of the energy savings recommendations and tools presented in this investigation.

Energy shortage, escalation of energy cost and climate change have led to an increased focus on energy conservation worldwide. In order to curb the increase in electricity demand, Eskom has introduced demand-side management (DSM) to improve energy efficiency and to shift peak-time load to off-peak periods in order to postpone additional capacity requirements. In the past, several mine DSM projects have been implemented without the use of system simulations as part of the analysis of project planning. Many of these projects are characterised by contractual energy saving targets that have not been met, projects that are delayed, potential energy savings projects that have been overlooked and additional savings that have not realised. This study demonstrates the potential of simulations to plan new and correct implemented DSM solutions. This is done by allowing analysis of energy consumption in complex technical systems and quantification of the savings potential of DSM interventions to inform design changes in order to attain energy savings. In applying simulations to a well-instrumented compressed air system, it was possible to compare the theoretical and measured values for system parameters. The simulation was fine-tuned for low-pressure operation (with the system operating well within design constraints) by incorporating estimated flow losses. By simulating high-pressure operation in which the system operates closer to design limits, the constraints that were experienced, were revealed. This application exemplifies the approach that has been adopted in the case studies to follow. The value of the use of simulation models for mine DSM projects Simulations that have been applied to four case studies demonstrate the use in improving existing DSM projects as well as in planning new DSM projects. Two case studies demonstrate the use of simulations in rectifying problems that have been encountered during the implementation of existing mine DSM projects. Simulations have been employed to propose corrections to these project implementations; this demonstrates significant value for the customer. In two additional case studies, the value of simulation models is demonstrated where simulations have been developed prior to the implementation of DSM projects. It demonstrates that projects can be implemented with less effort, in a shorter time span and at a reduced cost (both capital and man-hours) by using simulations in the planning phases of DSM projects. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.

Energy shortage, escalation of energy cost and climate change have led to an increased focus on energy conservation worldwide. In order to curb the increase in electricity demand, Eskom has introduced demand-side management (DSM) to improve energy efficiency and to shift peak-time load to off-peak periods in order to postpone additional capacity requirements. In the past, several mine DSM projects have been implemented without the use of system simulations as part of the analysis of project planning. Many of these projects are characterised by contractual energy saving targets that have not been met, projects that are delayed, potential energy savings projects that have been overlooked and additional savings that have not realised. This study demonstrates the potential of simulations to plan new and correct implemented DSM solutions. This is done by allowing analysis of energy consumption in complex technical systems and quantification of the savings potential of DSM interventions to inform design changes in order to attain energy savings. In applying simulations to a well-instrumented compressed air system, it was possible to compare the theoretical and measured values for system parameters. The simulation was fine-tuned for low-pressure operation (with the system operating well within design constraints) by incorporating estimated flow losses. By simulating high-pressure operation in which the system operates closer to design limits, the constraints that were experienced, were revealed. This application exemplifies the approach that has been adopted in the case studies to follow. The value of the use of simulation models for mine DSM projects Simulations that have been applied to four case studies demonstrate the use in improving existing DSM projects as well as in planning new DSM projects. Two case studies demonstrate the use of simulations in rectifying problems that have been encountered during the implementation of existing mine DSM projects. Simulations have been employed to propose corrections to these project implementations; this demonstrates significant value for the customer. In two additional case studies, the value of simulation models is demonstrated where simulations have been developed prior to the implementation of DSM projects. It demonstrates that projects can be implemented with less effort, in a shorter time span and at a reduced cost (both capital and man-hours) by using simulations in the planning phases of DSM projects. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013.

Indiana University-Purdue University Indianapolis (IUPUI) / Compressed air is a powerful source of stored energy and is used in a variety of applications varying from painting to pressing, making it a versatile tool for manufacturers. Due to the high cost and energy consumption associated with producing compressed air and it’s use within industrial manufacturing, it is often referred to as a fourth utility behind electricity, natural gas, and water. This is the reason why air compressors and associated equipment are often the focus for improvements in the eyes of manufacturing plant managers. As compressed air can be used in multiple ways, the methods used to extract and transfer the energy from this source vary as well. Compressed air can flow through different types of piping, such as aluminum, Polyvinyl Chloride (PVC), rubber, etc. with varying hydraulic diameters, and through different fittings such as 90-degree elbows, T-junctions, valves, etc. which can cause one of the major concerns related to managing the energy consumption of an air compressor, and that is the waste of air through leaks. Air leaks make up a considerable portion of the energy that is wasted in a compressed air system, as they cause a multitude of problems that the compressor will have to make up for to maintain the steady operation of the pneumatic devices on the manufacturing floor that rely on compressed air for their application. When air leaks are formed within the compressed air piping network, they act as continuous consumers and cause not only the siphoning off of said compressed air, put also reduce the pressure that is needed within the pipes. The air compressors will have to work harder to compensate for the losses in the pressure and the amount of air itself, causing an overconsumption of energy and power. Overworking the air compressor also causes the internal equipment to be stretched beyond its capabilities, especially if they are already running at full loads, reducing their total lifespans considerably. In addition, if there are multiple leaks close to the pneumatic devices on the manufacturing floor, the immediate loss in pressure and air can cause the devices to operate inefficiently and thus cause a reduction in production. This will all cumulatively impact the manufacturer considerably when it comes to energy consumption and profits. There are multiple methods of air leak detection and accounting that currently exist so as to understand their impact on the compressed air systems. The methods are usually conducted when the air compressors are running but during the time when there is no, or minimal, active consumption of the air by the pneumatic devices on the manufacturing floor. This time period is usually called non-production hours and generally occur during breaks or between employee shift changes. This time is specifically chosen so that the only air consumption within the piping is that of the leaks and thus, the majority of the energy and power consumed during this time is noted to be used to feed the air leaks. The collected data is then used to extrapolate and calculate the energy and power consumed by these leaks for the rest of the year. There are, however, a few problems that arise when using such a method to understand the effects of the leaks in the system throughout the year. One of the issues is that it is assumed that the air and pressure lost through the found leaks are constant even during the production hours i.e. the hours that there is active air consumption by the pneumatic devices on the floor, which may not be the case due to the increased air flow rates and varying pressure within the line which can cause an increase in the amount of air lost through the same orifices that was initially detected. Another challenge that arises with using only the data collected during a single non-production time period is that there may be additional air leaks that may be created later on, and the energy and power lost due to the newer air leaks would remain unaccounted for. As the initial estimates will not include the additional losses, the effects of the air leaks may be underestimated by the plant managers. To combat said issues, a continuous method of air leak analyses will be required so as to monitor the air compressors’ efficiency in relation to the air leaks in real time. By studying a model that includes both the production, and non-production hours when accounting for the leaks, it was observed that there was a 50.33% increase in the energy losses, and a 82.90% increase in the demand losses that were estimated when the effects of the air leaks were observed continuously and in real time. A real time monitoring system can provide an in-depth understanding of the compressed air system and its efficiency. Managing leaks within a compressed air system can be challenging especially when the amount of energy wasted through these leaks are unaccounted for. The main goal of this research was to find a nonintrusive way to calculate the amount of air as well as energy lost due to these leaks using time series pressure measurements. Previous studies have shown a strong relationship between the pressure difference, and the use of air within pneumatic lines, this correlation along with other factors has been exploited in this research to find a novel and viable method of leak accounting to develop a Continuous Air Leak Monitoring (CALM) system.