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.

The Swedish industry uses large volumes of compressed air. The compressed air process isenergy intensive and creates large amounts of excess heat. It is therefore important to utilizethe excess heat, optimize the operation of the compressors and to have a regular maintenanceon the system. This thesis is a pre-study to make a compressed air system energy efficient andis done in collaboration with Ljunghäll AB. Ljunghäll AB is one of Northern Europe's leadingdie casting companies and are located in Södra Vi, Sweden. The purpose is to describe andmap the compressed air system in the old part of the facility in Södra Vi. The thesis will alsogive an explanation of how Ljunghäll AB can improve the compressed air system. Providethem suggestions for energy savings and lower the environmental impact of production. Theobjective of the thesis is to create an understanding of how improvements in the compressedair system can be done by studying the operation, compressor, pipe system and leak detecting.The economic aspects of the solutions together with the effect of noise and engine operationof the compressors have not been taken into consideration. To reach improvement measures avisit to the facility in Södra Vi was made, where measuring and mapping was executed andthen compared with earlier studies and literature. The conclusions of the thesis show thatLjunghäll AB has a good operation and control of the compressors, through the variable speeddrive and steering system. It also showed that the choice of the existing compressors are goodfor their compressed air usage. The study also resulted in the following suggestions for theenergy efficiency and lowering of the environmental impact of production at Ljunghäll AB’scompressed air system: Water heat recovery, replacement of old pipes, cover the leakage,regular maintenance of compressors and fittings, training in compressed air for workers,centralized compressor central and sectioning of the pipe system.

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DSpace on 2017-11-28T18:25:00Z (GMT). No. of bitstreams: 1 silvajunior_gc_me_rcla.pdf: 1724008 bytes, checksum: c953406384f7a6ee2d78df6e9f2ae70b (MD5) Previous issue date: 2017-10-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Neste trabalho, apresentamos um relato de experimento realizado junto aos alunos de ensino fundamental de uma escola pública municipal e efetuamos o ajuste de curva dos dados observados por meio do método dos mínimos quadrados. Para tanto, discutimos a concepção e aplicação desse método a partir de resultados oriundos do cálculo diferencial, da álgebra linear e alguns conceitos estatísticos. Do cálculo diferencial estudamos a minimização dos erros de aproximação por meio da investigação dos pontos de mínimo da função erro. Da álgebra linear determinamos os parâmetros da função ajustada através da discussão e solução de um sistema de equações lineares resultante do conjunto de derivadas parciais nulas que estabelecem o ponto crítico da função erro. Da estatística utilizamos alguns conceitos e formulações que tratam da intensidade da relação entre as variáveis, bem como, das incertezas na variável dependente e nos parâmetros da função ajustada. / In this work, we present a report of an experiment carried out with elementary school students of a municipal public school, and we performed the curve adjustment of the observed data through the least squares method. For this, we discuss the conception and application of this method from results derived from differential calculus, linear algebra and some statistical concepts. From the differential calculation, we study the minimization of approximation errors by investigating the minimum points of the error function. From linear algebra, we determine the parameters of the adjusted function through the discussion and solution of a system of linear equations resulting from the set of null partial derivatives that establish the critical point of the error function. From statistics, we use some concepts and formulations that deal with the intensity of the relationship between variables, as well as the uncertainties in the dependent variable and the parameters of the adjusted function.

Energy storage is becoming a crucial element to the renewable energy grid, and new facilities will have to go somewhere. This thesis will propose to co-locate compressed air energy storage on a site with residential units, and a community park. This thesis will make the argument that co-locating a compressed air energy storage system with residential units could create a new start for the communities most harmed by fossil fuel infrastructure. This thesis will propose a design for a site in East Boston; a community badly scarred by heating oil and natural gas storage; with the goal of creating a model for healing both the physical site, and the social injustices created by the fossil fuel grid, arguing for using compressed air energy storage as both a spatial and an economic resource.

The diploma thesis deals with possibilities and subsequent proposal of individual measures to achieve the reduction of energy intensity in the company fischer Vyškov, s.r.o. At the beginning of the thesis is the analysis of the current state of the areas on which the work is further focused. These include the production of compressed air, cooling technology and lighting. The main cost-saving measures for the production of compressed air is a proposal to purchase a new compressor. For cooling, there are free cooling options, including the design of a dry cooler and its inclusion in the cooling circuit. The last part is the design of a new lighting system using LED lamps.

This diploma thesis deals with the design of pneumatic pressure switch with adjustable hysteresis. In the thesis is carried out the introduction in the theory of compressed air and research of the pressure switches at the market. Based on the gathered information and customer specification, the design draft of the pressure switch has been created. In the thesis are described three main parts of the prototype: transform of the pressure, adjustable hysteresis and synchronization of the microswitches. In the end of the thesis is described the testing of prototype and summary of the results.

Wind and solar technologies have experienced rapid market growth recently as a result of the growing interest for implementation of renewable energy. However, the intermittency of wind and solar power is a major obstacle to their broader use. The additional risks of unexpected interruptions and mismatch with demand have hindered the expansion of these two primary renewable resources. The goal of this research is to analyze an integrated energy system that includes a novel configuration of wind and solar coupled with two storage methods to make both wind and solar sources dispatchable during peak demand, thereby enabling their broader use. Named DSWiSS for Dispatchable Solar Wind Storage System, the proposed system utilizes compressed air energy storage (CAES) that is driven from wind energy and thermal storage supplied by concentrating solar thermal power in order to achieve this desired dispatchability. Although DSWiSS mimics the operation of a typical CAES facility, the replacement of energy derived from fossil fuels with energy generated from renewable resources makes this system unique. While current CAES facilities use off peak electricity to power their compressors, this system uses power from wind turbines. Also, rather than using natural gas for heating of the compressed air before its expansion through a turbine, DSWiSS uses solar thermal energy and thermal storage. For this research, two models were created; the first is a dynamic model of a 1.5 MW variable speed wind turbine, programmed in PSCAD/EMTDC, that utilizes rotor resistive control to maintain rated power output. This model simulates the dynamic response of the wind turbine to changing wind conditions as well as the nominal performance parameters at all wind speeds. The second model is a steady state thermodynamic simulation of the turbomachinery power unit in the DSWiSS facility. By assuming conditions similar to those of a currently operating CAES facility in McIntosh, Alabama, the model calculates the performance parameters of DSWiSS and estimates the relative energy input requirements. By combining these models with a levelized lifetime cost analysis estimates of the power system performance and the cost of energy for the DSWiSS facility were estimated. The combination of these components yielded an efficiency greater than 46% for the main power block and a nearly equal utilization of both renewable resources. It was also estimated that the overall system is only slightly more expensive per unit of electricity generated than the current technologies employed today, namely coal, nuclear, and natural gas, but is comparable to a stand-alone solar thermal facility. However, this economic analysis, though accurate with regard to the technologies chosen, will not be complete until cost values can be placed on some of the externalities associated with power generation such as fuel cost volatility, national security, and emissions. / text

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

Arbetet utfördes vid Norden Machinery i Kalmar. Norden Machinery blev år 1979 ett själv- ständigt bolag och är idag en världsledande leverantör av högpresterande tubfyllningsmaskiner. Processen i maskinerna är helautomatiserad och behandlar främst tuber av olika plastlaminat. I processen fylls tuben med sitt innehåll och överkanten värms sedan upp tillräckligt mycket för att den delvis smälta plasten ska kunna pressas samman och därmed försluta tuben. Innan överflödig plast i toppen på tuberna slutligen klipps till behöver tuberna kylas ner tillräckligt mycket för att inte lämna en dålig klippning. Norden Machinery vill idag se över kylstationens prestanda samt jämföra den mot alternativa lösningar. Syftet med arbetet var att genom teoretiska och praktiska utredningar undersöka olika koncept för att kyla tuberna före klippstationen. Prestandakriterier som utvärderades var kylförmåga, kostnad för ingående detaljer, förbrukning av tryckluft samt ljudnivå. En fördjupning i Nordens nuvarande lösning gjordes genom att mäta temperaturer på tubens överkant före och efter de olika stationerna i tubfyllningsmaskinen. Arbetet följde sedan en konceptgenereringsprocess där ett antal koncept skapades, testades och utvärderades med avseende på de uppsatta prestandakriterierna. De koncept som togs fram begränsades till att ersätta den del i tubfyllningsmaskinen som idag fungerar som kylstation. Ett framtaget koncept som tillsätter vattendimma till den kylande tryckluften visade sig genom mätningar kunna förbättra den kylande prestandan med närmare 15 % vid 25 % lägre luftflöde. Även ljudnivån påverkades positivt. Lösningen är mer komplex än nuvarande, och kräver vidare utvecklingsarbete, men har potential att klara särskilt krävande tuber som idag inte kan kylas tillräckligt effektivt. Ett slutligt koncept som likt dagens lösning kyler med tryckluft presenterades. Istället för runda utloppshål för luften används rektangulära spalter. Med den nya kylprofilen kan tillverknings- kostnaden reduceras med närmare 45 %, framförallt genom att färre moment och verktygsbyten krävs vid tillverkningen. / This work was conducted at Norden Machinery in Kalmar. Norden Machinery became an independent company in 1979 and is today a world-leading supplier of high-performance tube filling machines. The process in the machines is fully automated and handles mainly various types of laminated plastic tubes. In the process, the tube is filled with its content, the top of the tube is heated to partially melt the plastic and the top is then pressed together in order to seal the tube. Before any excess plastic at the top of the tubes is cut in the final step, the tubes need to cool down enough to not leave a bad cut. Norden Machinery wants to examine their current cooling station and further compare it with alternative solutions. The purpose of the work was that through theoretical and practical investigations examine different concepts of cooling. Performance criteria to be evaluated were cooling ability, cost of manufacturing, consumption of compressed air and noise level. Norden’s present solution was examined by temperature measurements at the top of the tube before and after the different stations in the tube filling machine. A concept generation process then followed, where a number of concepts were created, tested and evaluated with regard to the performance criteria. The concepts generated were limited to replacing the part of the tube filling machine that today serves as a cooling station. A generated concept that adds water mist to the compressed airflow could by measurements be demonstrated to increase the cooling performance by nearly 15 % at 25 % less airflow. The noise level was also positively affected. The solution is more complex than the current, and further development is needed, but the concept has the potential to cope with particularly demanding tubes that today cannot be cooled sufficiently. A final concept was presented, in which similar to the current solution compressed air is used for cooling the tube. Rectangular air outlets are used instead of round holes. With the new cooling profile, manufacturing costs can be reduced by close to 45%, mainly due to fewer operations and tool changes during the manufacturing.

Water or steam is added into the working fluid (often air) in gas turbines to improve the performance of gas turbine cycles. A typical application is the humidified gas turbine that has the potential to give high efficiencies, high specific power output, low emissions and low specific investment. A heat recovery system is integrated in the cycle with a humidifier for moisturizing the high-pressure air from the compressor as a kernel. Based on today’s gas turbines, the operating temperature and pressure in the humidifier are up to about 523 K and 40 bar, respectively. The operating temperature of the heat exchanger after the humidifier is up to 1773 K. The technology of water or steam addition is also used in the process of compressed air energy storage (CAES), and the operating pressure is up to 150 bar. Reliable thermodynamic properties of humid air are crucial for the process simulation and the traceable performance tests of turbomachinery and heat exchanger in the cycles. Several models have been proposed. However, the application range is limited to 400 K and 100 bar because of the limited experimental data for humid air. It is necessary to investigate the thermodynamic properties of humid air at elevated temperatures and pressures to fill in the knowledge gap. In this thesis, a new model is proposed based on the modified Redlich-Kwong equation of state in which a new cross interaction parameter between molecular oxygen and water is obtained from the fitting of the experimental data of oxygen-water system. The liquid phase is assumed to follow Henry’s law to calculate the saturated composition. The results of the new model are verified by the experimental data of nitrogen-water and oxygen-water systems from ambient temperature and pressure to 523 K and 200 bar, respectively. Properties of air-water system are predicted without any additional parameter and compared with the available experimental data to demonstrate the reliability of the new model for air-water system. The results of air-water system predicted using the new model are compared with those calculated using other real models. The comparison reveals that the new model has the same calculation accuracy as the best available model but can be used to a wider temperature and pressure range. The results of the new model are also compared with those of the ideal model and the ideal mixing model from ambient temperature and pressure to 1773 K and 200 bar to investigate the effect of the models on the thermodynamic properties of humid air. To investigate the impact of thermodynamic properties on the simulation of systems and their components, different models (ideal model, ideal mixing model and two real models) are used to calculate the thermodynamic properties of humid air in the simulation of the compressor, humidification tower, and heat exchanger in a humidified gas turbine cycle. The simulation reveals that a careful selection of a thermodynamic property model is crucial for the cycle design. The simulation results provide a useful tool for predicting the performance of the system and designing the humidified cycle components and systems. / QC 20100902