Various commercial software packages are available for simulating compressed air network operations. However, none of these software packages are able to dynamically prioritise compressor selection on large compressed air networks in the mining industry. In this dissertation, a dynamic compressor selector (DCS) will be developed that will actively and continuously monitor system demand. The software will ensure that the most suitable compressors, based on efficiency and position in the compressed air network, are always in operation. The study will be conducted at a platinum mine. Compressed air flow and pressure requirements will be maintained without compromising mine safety procedures. Significant energy savings will be realised. DCS will receive shaft pressure profiles from each of the shafts’ surface compressed air control valves. These parameters will be used to calculate and predict the compressed air demand. All pipe friction losses and leaks will be taken into account to determine the end-point pressure losses at different flow rates. DCS will then prioritise the compressors of the compressed air network based on the overall system requirement. This software combines the benefits of supply-side and demand-side management. Potential energy savings with DCS were proven and compressor cycling reduced. A DCS user-friendly interface was created to easily set up any mine’s compressed air network. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

The energy provider in South Africa, Eskom, faces an increasing electricity demand. The need to ensure sufficient supply gave rise to Demand Side Management (DSM) projects scheme. The DSM focus has shifted to the mining sector in South Africa. The large electricity use of the mining sector ensured the need for Energy Services Companies (ESCo’s). The ESCo is contracted to ensure energy savings of DSM projects implemented within the multiple sectors such as mining industry. The mining sector business model has the constant pressure to increase gold production. This pressure to expand has led to rapid expansion plans to increase the gold output for the relevant company. The expansion process and production increase in turn increases the electricity consumption. Compressed air use is a large contributing factor to the monthly electricity use as it is widely used within the mine sector. The implementation of a DSM project on the compressed air ring of an expanding gold mine was the focus of the study. This case study focused on an expanding gold mine within South Africa. The DSM lifecycle was followed to initially determine the DSM saving potential. The possible control strategies were investigated with simulation models and savings calculations. The viable option was to be implemented with a preliminary control philosophy. Results were in turn compared with the initial investigations and control philosophy. The deviations as experienced with implementation were addressed and a potential sustainable control philosophy for an expanding gold mine was constructed. The results indicated, verified Eskom peak clip electricity savings of 2.165 MW of the 2.4 MW target. The energy efficiency component for these performance assessment months was 1.944 MW of the targeted 1.5 MW. The sustainability of the system was proven with production increase on an expanding gold mine. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2013

The world is currently experiencing major issues in the energy sector. The ever-growing human population, limited energy resources and the effect of greenhouse gas emissions have become major global concerns for the energy sector, including the electricity generation sector. This dilemma caused electricity providers to revise their generation methods and created a major need for consumers to utilise electricity more efficiently. Demand side management (DSM) is one initiative developed for consumers to efficiently utilise electricity. Due to their high electricity consumption and technical skills, mines are ideal targets for the implementation of DSM strategies. Therefore, the focus of this study was to investigate South African mines for possible implementation of DSM strategies on their compressed air networks. Compressed air networks at South African mines are relatively old and inadequately maintained. This causes inefficient distribution and use of compressed air. The study will therefore focus on reconfiguring mining compressed air networks for cost savings. Cost savings include financial savings on electricity bills, implementation costs and decreased maintenance. Through several investigations, the possibility of implementing energy savings strategies to reconfigure the compressed air networks of two South African mines was identified. Reconfiguring the networks would respectively entail interconnecting two shafts and relocating a compressor from an abandoned shaft to a fully productive shaft. Theoretical simulations were developed to determine the networks’ responses to the reconfiguration strategies. The simulations assisted in exposing the viability of implementing the reconfiguration strategies on the respective compressed air networks. Positive responses were obtained from the simulations and proposals were made to the respective mines for possible implementation. The proposed initiatives were implemented on the respective mines’ compressed air networks. After implementation of the interconnection strategy, a consecutive three-month performance assessment period commenced to prove the viability of the proposed savings. An average power saving of 1 700 kW was achieved during the performance assessment period. The proposed initiative to relocate the compressor is currently being implemented. A financial saving of approximately R8.9 million per annum was achieved by implementing the interconnection strategy. The large financial saving was due to the utilisation of the mine’s salvaged equipment. Further savings were achieved by the decreased maintenance on the mine’s compressors. Due to the successful implementation of the interconnection strategy, it is safe to state that cost savings can be achieved by reconfiguring mining compressed air networks. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2014

Various commercial software packages are available for simulating compressed air network operations. However, none of these software packages are able to dynamically prioritise compressor selection on large compressed air networks in the mining industry. In this dissertation, a dynamic compressor selector (DCS) will be developed that will actively and continuously monitor system demand. The software will ensure that the most suitable compressors, based on efficiency and position in the compressed air network, are always in operation. The study will be conducted at a platinum mine. Compressed air flow and pressure requirements will be maintained without compromising mine safety procedures. Significant energy savings will be realised. DCS will receive shaft pressure profiles from each of the shafts’ surface compressed air control valves. These parameters will be used to calculate and predict the compressed air demand. All pipe friction losses and leaks will be taken into account to determine the end-point pressure losses at different flow rates. DCS will then prioritise the compressors of the compressed air network based on the overall system requirement. This software combines the benefits of supply-side and demand-side management. Potential energy savings with DCS were proven and compressor cycling reduced. A DCS user-friendly interface was created to easily set up any mine’s compressed air network. / Thesis (MIng (Mechanical Engineering))--North-West University, Potchefstroom Campus, 2013

The energy provider in South Africa, Eskom, faces an increasing electricity demand. The need to ensure sufficient supply gave rise to Demand Side Management (DSM) projects scheme. The DSM focus has shifted to the mining sector in South Africa. The large electricity use of the mining sector ensured the need for Energy Services Companies (ESCo’s). The ESCo is contracted to ensure energy savings of DSM projects implemented within the multiple sectors such as mining industry. The mining sector business model has the constant pressure to increase gold production. This pressure to expand has led to rapid expansion plans to increase the gold output for the relevant company. The expansion process and production increase in turn increases the electricity consumption. Compressed air use is a large contributing factor to the monthly electricity use as it is widely used within the mine sector. The implementation of a DSM project on the compressed air ring of an expanding gold mine was the focus of the study. This case study focused on an expanding gold mine within South Africa. The DSM lifecycle was followed to initially determine the DSM saving potential. The possible control strategies were investigated with simulation models and savings calculations. The viable option was to be implemented with a preliminary control philosophy. Results were in turn compared with the initial investigations and control philosophy. The deviations as experienced with implementation were addressed and a potential sustainable control philosophy for an expanding gold mine was constructed. The results indicated, verified Eskom peak clip electricity savings of 2.165 MW of the 2.4 MW target. The energy efficiency component for these performance assessment months was 1.944 MW of the targeted 1.5 MW. The sustainability of the system was proven with production increase on an expanding gold mine. / MIng (Computer and Electronic Engineering), North-West University, Potchefstroom Campus, 2013

abstract: A low cost expander, combustor device that takes compressed air, adds thermal energy and then expands the gas to drive an electrical generator is to be designed by modifying an existing reciprocating spark ignition engine. The engine used is the 6.5 hp Briggs and Stratton series 122600 engine. Compressed air that is stored in a tank at a particular pressure will be introduced during the compression stage of the engine cycle to reduce pump work. In the modified design the intake and exhaust valve timings are modified to achieve this process. The time required to fill the combustion chamber with compressed air to the storage pressure immediately before spark and the state of the air with respect to crank angle is modeled numerically using a crank step energy and mass balance model. The results are used to complete the engine cycle analysis based on air standard assumptions and air to fuel ratio of 15 for gasoline. It is found that at the baseline storage conditions (280 psi, 70OF) the modified engine does not meet the imposed constraints of staying below the maximum pressure of the unmodified engine. A new storage pressure of 235 psi is recommended. This only provides a 7.7% increase in thermal efficiency for the same work output. The modification of this engine for this low efficiency gain is not recommended. / Dissertation/Thesis / M.S. Mechanical Engineering 2011

The thesis is focused on the area of wastewater treatment. There is a solution possibility of using flotation for the removal of phosphorus precipitates formed during the tertiary treatment of wastewater. The first part is devoted to a general description of wastewater treatment, there is also described as a flotation separation technology and precipitation of phosphorus. The second part is practically oriented. It describes the experimental equipment used for the precipitation of phosphorus and subsequent removal of the precipitate flotation, during the experiment and the results obtained.

This diploma thesis deals with possibilities of accumulation of electricity generated by renewable sources with unstable production. Several goals were set by an assignment of this thesis. Within a research, current trends of the accumulation are presented in detail on examples of specific representatives with their technical parameters and economic possibilities. Further, an unstable source of electricity – the wind farm of three power plants Multibrid 5000 with all its parameters and operational details is defined for purposes of individual designs of accumulation systems. Firstly, the detailed design of an advanced compressed air energy storage (A-CAES) is realized. It includes a thermodynamic calculation of chosen components, their partial technical solutions, a financial evaluation of investment and a determination of theoretical payback period. Furthermore, the design for accumulators Tesla Powerpack is realized. It contains a calculation of individual system parameters, a financial evaluation of investment and a determination of theoretical payback period. Last part of the thesis is dedicated to a comparison and an evaluation of the achieved results of both realized methods of the electricity accumulation. In the end, A-CAES is chosen as more perspective variation.

This diploma thesis is specialized on problems of electrical energy accumulation from renewable resources. This renewable resources used in Czech Republic are described in the first part. Next, in the second chapter is identification with principles of electrical energy accumulation. In the third part, there is a proposal of electrical energy accumulation system which makes a supply of electrical energy from photovoltaic system by the help of accumulation system in compressed air equally. In the final part, there is a total analysis of technical economic aspect for proposed system.

The diploma thesis is focused on problem of accumulating electric energy from renewable resources. The first section describes renewable energy sources, which are possible to use in the Czech Republic and principles of accumulating electric energy. In the following section are suggested systems of accumulating energy to accumulators by compressed air and pumped storage power station. These systems are proposed for uniform power supply from photovoltaic power station to electric power network all day. In conclusion, the suggested systems are compared from economic-technical perspective.