Eskom provides 98% of South Africa’s ever increasing electricity demand. The mining sector is a vital contributor to the economy, but also consumes vast amounts of electricity. This sector is responsible for almost 15% of the country’s electricity usage. Mines heavily depend on the supply of cold water and air. Refrigeration systems are therefore constantly operational and can account for 25% of a mine’s electricity costs. The need therefore exists to investigate possible energy savings initiatives. Refrigeration systems are typically used to lower the temperature of water and air. Bulk Air Coolers (BACs) are used to produce cold air. The aim of this study is to investigate possible electricity cost savings in a mine refrigeration system. This can be achieved by enabling equipment to dynamically adapt to changes in their environment. Electricity usage reduction has the greatest financial impact if it occurs during Eskom peak periods. Time-dependent schedules of operation are therefore used to achieve this objective. Due to the lack of such a controller in the mining industry, the focus of this study is a BAC control system. A BAC controller would be able to follow guidelines that could lead to electricity cost savings. It was therefore developed and incorporated in the Real-time Energy Management System (REMS). The BAC controller combines various inputs and constraints to determine the output. An electricity usage reduction during the Eskom evening peak period was consequently achieved. The BAC controller was implemented on three sites. Electrical energy usage during the evening peak period was reduced via the load shifting method. This aids Eskom in their effort to reduce the peak period demand. Air temperature and dam levels were closely monitored during the peak period. If any preset condition was violated, the load shifting was abandoned for that day. It was shown that a total power reduction of 7 MW is possible between the three sites. The electricity savings occurred in the evening peak period. A calculation was made to determine the possible annual savings by using the achieved daily cost savings. The winter months were not included in the calculation. An annual cost saving of R1 166 694.41 is therefore possible without having to reduce output quantities. / MIng(Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

Eskom provides 98% of South Africa’s ever increasing electricity demand. The mining sector is a vital contributor to the economy, but also consumes vast amounts of electricity. This sector is responsible for almost 15% of the country’s electricity usage. Mines heavily depend on the supply of cold water and air. Refrigeration systems are therefore constantly operational and can account for 25% of a mine’s electricity costs. The need therefore exists to investigate possible energy savings initiatives. Refrigeration systems are typically used to lower the temperature of water and air. Bulk Air Coolers (BACs) are used to produce cold air. The aim of this study is to investigate possible electricity cost savings in a mine refrigeration system. This can be achieved by enabling equipment to dynamically adapt to changes in their environment. Electricity usage reduction has the greatest financial impact if it occurs during Eskom peak periods. Time-dependent schedules of operation are therefore used to achieve this objective. Due to the lack of such a controller in the mining industry, the focus of this study is a BAC control system. A BAC controller would be able to follow guidelines that could lead to electricity cost savings. It was therefore developed and incorporated in the Real-time Energy Management System (REMS). The BAC controller combines various inputs and constraints to determine the output. An electricity usage reduction during the Eskom evening peak period was consequently achieved. The BAC controller was implemented on three sites. Electrical energy usage during the evening peak period was reduced via the load shifting method. This aids Eskom in their effort to reduce the peak period demand. Air temperature and dam levels were closely monitored during the peak period. If any preset condition was violated, the load shifting was abandoned for that day. It was shown that a total power reduction of 7 MW is possible between the three sites. The electricity savings occurred in the evening peak period. A calculation was made to determine the possible annual savings by using the achieved daily cost savings. The winter months were not included in the calculation. An annual cost saving of R1 166 694.41 is therefore possible without having to reduce output quantities. / MIng(Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2015

This work is concerned with evaluating and studying the possibilities of enhancing natural ventilation performance and its use as a passive cooling strategy in walk-up public housing blocks within the Egyptian desert climatic region. This research attempts to maximize the benefits from the vast investments made in housing projects in Egypt through providing thermally comfortable housing prototypes that could use by contrast less energy for cooling purposes. This is considered essential in the light of the current concerns about energy all over the world. Egypt was devided to seven different climatic regions by the Egyptian organization for energy conservation and planning. The Egyptian desert climatic region, which was chosen as the research context, is the largest climatic region of Egypt. Most of the Egyptian new cities that accommodate the majority of the recent public housing projects are located within this desert climatic region that represents the typical hot arid climate characteristics. Nationally, the problem of the misuse of the housing prototyping was spotted. According to previous researchers, the same basic prototypical designs are being built all over the country without giving enough consideration to the actual effects of different climates and the diversity in the residents social needs. Regionally, within the Egyptian desert climatic region, the harsh climatic conditions rate the problem of achieving thermal comfort within these housing prototypes as the most urgent problem that needs to be examined in depth. A pilot study that used observation and monitoring methods was conducted in the New Al-Minya city (The representative city of the desert climatic design region) in order to closely investigate this problem and identify its dimensions. The results confirmed thermal discomfort conditions of the housing prototypes built there, especially during the hot summer period. The passive design strategies analysis of the climatic context indicated that night purge ventilation is the most effective passive strategy that could enhance thermal comfort. These results go along with the rule of natural ventilation in reducing the used energy for cooling and the actually massive national income spent on these housing prototypes encourage this work so to concentrate on natural ventilation. Different studies using multi-approaches research techniques were employed in order to achieve the main aim of the research. These techniques included; literature review, monitoring, questionnaire and computer simulation.A critical literature review was conducted including; the physical science of natural ventilation, its strategic design as well as the design measures that control natural ventilation and the airflow in; the macro, intermediate and micro design levels. The results of the investigations were discussed and interpreted in the light of this review. A representative case study was chosen for the study. The natural ventilation performance in the case study was quantitatively and qualitatively evaluated through conducting field objective and subjective assessment respectively. In evaluation study, the thermal performance of the case study under different ventilation scenarios was monitored, the airflow inside it was simulated using CFD (computational fluid dynamics) software “FloVent” and a sample of residents were questioned. This study identified many problems associated natural ventilation uses and indicated its poor performance within the case study. A number of design measures were formulated based on the literature review and considering the evaluation study results along with the research context nature. The proposed natural ventilation design measures were applied to the case studies and their effectiveness in terms of enhancing the natural ventilation performance was quantified using “FloVent”. Results reported that the proposed natural ventilation design measures could significantly enhance the natural ventilation performance inside the case study quantitatively and qualitatively. This in turn maximizes the potential of providing thermal comfort by using both natural ventilation strategies; comfort ventilation and night purge ventilation. However, all the applied measures could not achieve neither an acceptable airspeed at any of the case study spaces nor a good airflow circulation at some of its spaces. It can be concluded that the current design of the case study can not achieve quality airflow without the use of the mechanical assisted ventilation. In general, it seems very difficult to optimize the air velocity within all spaces in a very dense multi-space design like this case study. A new design that considers natural ventilation and its drivers has to be introduced.

An investigation into an appropriate urban design response to the development of the Gautrain Rapid Rail Link station in the Pretoria CBD, which acts as a catalyst for urban renewal and social development. Focus is aimed at the technical resolution according to the climatic conditions. / Dissertation (MArch (Prof))--University of Pretoria, 2006. / Architecture / unrestricted

This study describes the development and use of a mathematical model that will enable mine operators to minimise the costs of electricity consumed by the ventilation and refrigeration systems used for environmental control in deep mines. This model was calibrated and tested by using actual data from a gold mine near Welkom in South Africa. In a first simulation, the mine's current practice of controlling conditions to a wet bulb temperature (Twb) of 25S°C, was optimised. The model demonstrated that this environmental condition could be sustained at lower electricity consumption. In so doing, the mine realised a saving of 30 000 kWh per day. The energy saving and load management led to a cost saving of R 1.5 million per year. However, a better indicator of environmental conditions is the Air Cooling Power index, (ACP). Research has shown that for hard physical work in hot conditions workers need an ACP of 300 w/m2. It was found that the case study mine actually supplied their workplace with a cooling capacity of 422 w/m2. The new model optimised the refrigeration and ventilation systems in such a manner that the workers were supplied with exactly 300 w/m2, no more and no less. It was found that by doing this, an electricity saving of 57 600 kWh per day could be realised when compared with the current mine practices. The energy saving and load management led to a potential cost saving of R 2.55 million per year. (Certain capital costs, such as for variable speed drives may have to be incurred to realise these savings.) The new model could be further extended to take advantage of the new Real Time Price offerings from Eskom It will be able to identify an operating point for the refrigeration and ventilation systems to supply 300 w/m2 for the workers, in real time, at the lowest electricity cost. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

This study describes the development and use of a mathematical model that will enable mine operators to minimise the costs of electricity consumed by the ventilation and refrigeration systems used for environmental control in deep mines. This model was calibrated and tested by using actual data from a gold mine near Welkom in South Africa. In a first simulation, the mine's current practice of controlling conditions to a wet bulb temperature (Twb) of 25S°C, was optimised. The model demonstrated that this environmental condition could be sustained at lower electricity consumption. In so doing, the mine realised a saving of 30 000 kWh per day. The energy saving and load management led to a cost saving of R 1.5 million per year. However, a better indicator of environmental conditions is the Air Cooling Power index, (ACP). Research has shown that for hard physical work in hot conditions workers need an ACP of 300 w/m2. It was found that the case study mine actually supplied their workplace with a cooling capacity of 422 w/m2. The new model optimised the refrigeration and ventilation systems in such a manner that the workers were supplied with exactly 300 w/m2, no more and no less. It was found that by doing this, an electricity saving of 57 600 kWh per day could be realised when compared with the current mine practices. The energy saving and load management led to a potential cost saving of R 2.55 million per year. (Certain capital costs, such as for variable speed drives may have to be incurred to realise these savings.) The new model could be further extended to take advantage of the new Real Time Price offerings from Eskom It will be able to identify an operating point for the refrigeration and ventilation systems to supply 300 w/m2 for the workers, in real time, at the lowest electricity cost. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2004.

The South African economy, which is largely based on heavy industry such as minerals extraction and processing, is by nature very energy intensive. Based on the abundance of coal resources, electricity in South Africa remains amongst the cheapest in the world. Whilst the low electricity price has contributed towards a competitive position, it has also meant that our existing electricity supply is often taken for granted. The economic and environmental benefits of energy efficiency have been well documented. Worldwide, nations are beginning to face up to the challenge of sustainable energy - in other words to alter the way that energy is utilised so that social, environmental and economic aims of sustainable development are supported. South Africa as a developing nation recognises the need for energy efficiency, as it is the most cost effective way of meeting the demands of sustainable development. South Africa, with its unique economic, environmental and social challenges, stands to benefit the most from implementing energy efficiency practices. The Energy Efficiency Strategy for South Africa takes its mandate from the South African White Paper on Energy Policy. It is the first consolidated governmental effort geared towards energy efficiency practices throughout South Africa. The strategy allows for the immediate implementation of low-cost and no-cost interventions, as well as those higher-cost measures with short payback periods. An initial target has been set for an across sector energy efficiency improvement of 12% by 2014. Thermal and energy system simulation is globally recognised as one of the most effective and powerful tools to improve overall energy efficiency. However, because of the usual extreme mathematical nature of most simulation algorithms, coupled with the historically academic environment in which most simulation software is developed, valid perceptions exist that system simulation is too time consuming and cumbersome. It is also commonly known that system simulation is only effective in the hands of highly skilled operators, which are specialists in their prospective fields. Through previous work done in the field, and the design of a dynamic thermal and energy system simulation scheme for cross industry applications, it was shown that system simulation has evolved to such an extent that these perceptions are not valid any more. The South African mining and commercial building industries are two of the major consumers of electricity within South Africa. By improving energy efficiency practices within the building and mining industry, large savings can be realised. An extensive investigation of the literature showed that no general suitable computer simulation software for cross industry mining and building thermal and energy system simulation could be found. Because the heating, ventilation and air conditioning (HVAC) of buildings, closely relate to the ventilation and cooling systems of mines, valuable knowledge from this field was used to identify the requirements and specifications for the design of a new single cross industry dynamic integrated thermal and energy system simulation tool. VISUALQEC was designed and implemented to comply with the needs and requirements identified. A new explicit system component model and explicit system simulation engine, combined with a new improved simulation of mass flow through a system procedure, suggested a marked improvement on overall simulation stability, efficiency and speed. The commercial usability of the new simulation tool was verified for building applications by doing an extensive building energy savings audit. The new simulation tool was further verified by simulating the ventilation and cooling (VC) and underground pumping system of a typical South African gold mine. Initial results proved satisfactory but, more case studies to further verify the accuracy of the implemented cross industry thermal and energy system simulation tool are needed. Because of the stable nature of the new VISUALQEC simulation engine, the power of the simulation process can be further extended to the mathematical optimisation of various system variables. In conclusion, this study highlighted the need for new simulation procedures and system designs for the successful implementation and creation of a single dynamic thermal and energy system simulation tool for cross industry applications. South Africa should take full advantage of the power of thermal and energy system simulation towards creating a more energy efficient society. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.

The South African economy, which is largely based on heavy industry such as minerals extraction and processing, is by nature very energy intensive. Based on the abundance of coal resources, electricity in South Africa remains amongst the cheapest in the world. Whilst the low electricity price has contributed towards a competitive position, it has also meant that our existing electricity supply is often taken for granted. The economic and environmental benefits of energy efficiency have been well documented. Worldwide, nations are beginning to face up to the challenge of sustainable energy - in other words to alter the way that energy is utilised so that social, environmental and economic aims of sustainable development are supported. South Africa as a developing nation recognises the need for energy efficiency, as it is the most cost effective way of meeting the demands of sustainable development. South Africa, with its unique economic, environmental and social challenges, stands to benefit the most from implementing energy efficiency practices. The Energy Efficiency Strategy for South Africa takes its mandate from the South African White Paper on Energy Policy. It is the first consolidated governmental effort geared towards energy efficiency practices throughout South Africa. The strategy allows for the immediate implementation of low-cost and no-cost interventions, as well as those higher-cost measures with short payback periods. An initial target has been set for an across sector energy efficiency improvement of 12% by 2014. Thermal and energy system simulation is globally recognised as one of the most effective and powerful tools to improve overall energy efficiency. However, because of the usual extreme mathematical nature of most simulation algorithms, coupled with the historically academic environment in which most simulation software is developed, valid perceptions exist that system simulation is too time consuming and cumbersome. It is also commonly known that system simulation is only effective in the hands of highly skilled operators, which are specialists in their prospective fields. Through previous work done in the field, and the design of a dynamic thermal and energy system simulation scheme for cross industry applications, it was shown that system simulation has evolved to such an extent that these perceptions are not valid any more. The South African mining and commercial building industries are two of the major consumers of electricity within South Africa. By improving energy efficiency practices within the building and mining industry, large savings can be realised. An extensive investigation of the literature showed that no general suitable computer simulation software for cross industry mining and building thermal and energy system simulation could be found. Because the heating, ventilation and air conditioning (HVAC) of buildings, closely relate to the ventilation and cooling systems of mines, valuable knowledge from this field was used to identify the requirements and specifications for the design of a new single cross industry dynamic integrated thermal and energy system simulation tool. VISUALQEC was designed and implemented to comply with the needs and requirements identified. A new explicit system component model and explicit system simulation engine, combined with a new improved simulation of mass flow through a system procedure, suggested a marked improvement on overall simulation stability, efficiency and speed. The commercial usability of the new simulation tool was verified for building applications by doing an extensive building energy savings audit. The new simulation tool was further verified by simulating the ventilation and cooling (VC) and underground pumping system of a typical South African gold mine. Initial results proved satisfactory but, more case studies to further verify the accuracy of the implemented cross industry thermal and energy system simulation tool are needed. Because of the stable nature of the new VISUALQEC simulation engine, the power of the simulation process can be further extended to the mathematical optimisation of various system variables. In conclusion, this study highlighted the need for new simulation procedures and system designs for the successful implementation and creation of a single dynamic thermal and energy system simulation tool for cross industry applications. South Africa should take full advantage of the power of thermal and energy system simulation towards creating a more energy efficient society. / Thesis (Ph.D. (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2005.