Air compressor systems play a large role in modern industry. These compressors can account for a significant portion of a manufacturing facility’s electric consumption and any increase in efficiency can lead to economic benefits. Air compressors are sensitive to ambient conditions, as evidenced by the fact that compressing cooler and drier air decreases the amount of work required to compress the air. A thermodynamic model of an air compressor system was developed and several cases were run by using both vapor compression and absorption cycle chillers to cool and dehumidify the inlet air. The results show that the performance increases as much as 8 percent for the compressor system with absorption inlet cooling and as much as 5 percent when using vapor compression inlet cooling. Climates with higher humidity and temperatures can see the most benefits from inlet air cooling and dehumidification.

In Taiwan, most of the energy relies on imports due to few natural resources. Further more, scientists estimate that crude oil will be depleted within 40 years. A high cost energy era has arrived. Skyrocketing oil prices have a severe negative impact on the cost structure of the Taiwan Power Company (TPC), which has an estimated deficit of NT$70 billion in 2007. TPC has faced a difficult dilemma: whether to raise the electricity rate or become bankrupt. Eventually, the government has to intervene. The Kyoto Protocol was in effect in February 2005. It is expected that the environmental convention of reducing of CO2 will become an international movement following ISO14000. With every one kilowatt hour of electricity is generated by TPC, 638g of CO2 were produced. The products of made-in-Taiwan will not received international approval and will be boycotted by the International market if the energy efficiency of national enterprise is too low. Air compressor system, which is as important as water and electricity, is popularly used in almost all industries. However, its high energy-consumption and low efficiency system is seldom noticed. The energy cost of air compressor system is about 80% of the total operational cost which includes the electricity costs of all the machinery and lightings. How to improve air compressor efficiency plays an important role in the manufacture¡¦s production cost and its competition against other industries. Facing fierce competition and low profit, the industries must not only continuously innovate and reduce the cost to enhance competition ability for keeping market share, but also increase energy efficiency and reduce the emission of greenhouse gases by the green production method meeting the environmental requirement. The report is the summary of the interviews with many industry leaders who are involved in the air compressor production or the government officials who are in charge of energy-saving promotion. It also combines with the data of actual measurement of the compressor systems to research if the investment willingness of manufacturers is reflected by their operation cost, operation strategy, the risky consideration when facing law and the information getting of compressor energy-saving. The results of the study are: Clarify the main factors which influence the investment willingness to compressor energy-saving. (A) The cost side: The investment willingness is influenced by the cognition of the leaders of manufacturer unit or business owner to compressor system cost. (B) The strategy side: The investment willingness is influenced by the cognition of the leaders of manufacturer unit or business owner to the operation strategy on compressor system. (C) The legal side: The investment willingness is influenced by the cognition of the leaders of manufacturer unit or business owner to the legal affection to business. (D) The information side: The investment willingness is influenced by getting the information of energy-saving of compressor system. Finally, the study proposes a feasible project to the industries and the government officials who promote energy saving.

Indiana University-Purdue University Indianapolis (IUPUI) / The compressed air system is widely used throughout the industry. Air compressors are one of the most costly systems to operate in industrial plants in terms of energy consumption. Therefore, it becomes one of the primary targets when it comes to electrical energy and load management practices. Load forecasting is the first step in developing energy management systems both on the supply and user side. A comprehensive literature review has been conducted, and there was a need to study if predicting compressed air system’s load is a possibility. System’s load profile will be valuable to the industry practitioners as well as related software providers in developing better practice and tools for load management and look-ahead scheduling programs. Feed forward neural networks (FFNN) and long short-term memory (LSTM) techniques have been used to perform 15 minutes ahead prediction. Three cases of different sizes and control methods have been studied. The results proved the possibility of the forecast. In this study two control methods have been developed by using the prediction. The first control method is designed for variable speed driven air compressors. The goal was to decrease the maximum electrical load for the air compressor by using the system's full operational capabilities and the air receiver tank. This goal has been achieved by optimizing the system operation and developing a practical control method. The results can be used to decrease the maximum electrical load consumed by the system as well as assuring the sufficient air for the users during the peak compressed air demand by users. This method can also prevent backup or secondary systems from running during the peak compressed air demand which can result in more energy and demand savings. Load management plays a pivotal role and developing maximum load reduction methods by users can result in more sustainability as well as the cost reduction for developing sustainable energy production sources. The last part of this research is concentrated on reducing the energy consumed by load/unload controlled air compressors. Two novel control methods have been introduced. One method uses the prediction as input, and the other one doesn't require prediction. Both of them resulted in energy consumption reduction by increasing the off period with the same compressed air output or in other words without sacrificing the required compressed air needed for production. / 2019-12-05

<div>The compressed air system is widely used throughout the industry. Air compressors are one of the most costly systems to operate in industrial plants in therms of energy consumption. Therefore, it becomes one of the primary target when it comes to electrical energy and load management practices. Load forecasting is the first step in developing energy management systems both on the supply and user side. A comprehensive literature review has been conducted, and there was a need to study if predicting compressed air system’s load is a possibility. </div><div><br></div><div>System’s load profile will be valuable to the industry practitioners as well as related software providers in developing better practice and tools for load management and look-ahead scheduling programs. Feed forward neural networks (FFNN) and long short-term memory (LSTM) techniques have been used to perform 15 minutes ahead prediction. Three cases of different sizes and control methods have been studied. The results proved the possibility of the forecast. In this study two control methods have been developed by using the prediction. The first control method is designed for variable speed driven air compressors. The goal was to decrease the maximum electrical load for the air compressor by using the system's full operational capabilities and the air receiver tank. This goal has been achieved by optimizing the system operation and developing a practical control method. The results can be used to decrease the maximum electrical load consumed by the system as well as assuring the sufficient air for the users during the peak compressed air demand by users. This method can also prevent backup or secondary systems from running during the peak compressed air demand which can result in more energy and demand savings. Load management plays a pivotal role and developing maximum load reduction methods by users can result in more sustainability as well as the cost reduction for developing sustainable energy production sources. The last part of this research is concentrated on reducing the energy consumed by load/unload controlled air compressors. Two novel control methods have been introduced. One method uses the prediction as input, and the other one doesn't require prediction. Both of them resulted in energy consumption reduction by increasing the off period with the same compressed air output or in other words without sacrificing the required compressed air needed for production.</div><div><br></div>

The generation of compressed air comprises 20% of the total electricity usage in the mining industry, although compressed air is often seen as a free source of energy. There are however significant costs associated with generating compressed air and maintaining a compressed air system. There are several methods to optimise the electricity used to generate compressed air. The focus of this study is on one of these methods – the implementation of a dynamic air compressor selector. A Dynamic Compressor Selector (DCS) system was developed to fulfil this purpose. DCS is a system that combines demand- and supply-side management of a compressed air network. DCS calculates a pressure set point for compressors and schedules the compressors according to the demand from the end-users. End-users include shafts, plants, workshops and smelters. DCS takes all of the compressors and end-users into consideration while doing the calculations. This dissertation focuses on the DCS implementation process and on the problems encountered by previous authors while implementing the DCS technology. Additional problems were encountered while the DCS technology was implemented. DCS was however still successfully implemented. This study will expand the implementation procedure to ensure that the technology can be implemented successfully in the future. DCS was implemented at a platinum mine in South Africa where it was able to calculate pressure set points for the compressors. DCS was able to accurately match the supply of, and demand for compressed air closely, resulting in lower overall compressed air usage. DCS improved compressor scheduling and control, limiting compressor cycling. Improved compressor scheduling and control resulted in significant decreases in the electricity used to generate compressed air at the mine. A target average evening peak clip of 2.197 MW was simulated, set and achieved. Evening peak clip power savings in excess of an average of 3 MW were achieved. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

The generation of compressed air comprises 20% of the total electricity usage in the mining industry, although compressed air is often seen as a free source of energy. There are however significant costs associated with generating compressed air and maintaining a compressed air system. There are several methods to optimise the electricity used to generate compressed air. The focus of this study is on one of these methods – the implementation of a dynamic air compressor selector. A Dynamic Compressor Selector (DCS) system was developed to fulfil this purpose. DCS is a system that combines demand- and supply-side management of a compressed air network. DCS calculates a pressure set point for compressors and schedules the compressors according to the demand from the end-users. End-users include shafts, plants, workshops and smelters. DCS takes all of the compressors and end-users into consideration while doing the calculations. This dissertation focuses on the DCS implementation process and on the problems encountered by previous authors while implementing the DCS technology. Additional problems were encountered while the DCS technology was implemented. DCS was however still successfully implemented. This study will expand the implementation procedure to ensure that the technology can be implemented successfully in the future. DCS was implemented at a platinum mine in South Africa where it was able to calculate pressure set points for the compressors. DCS was able to accurately match the supply of, and demand for compressed air closely, resulting in lower overall compressed air usage. DCS improved compressor scheduling and control, limiting compressor cycling. Improved compressor scheduling and control resulted in significant decreases in the electricity used to generate compressed air at the mine. A target average evening peak clip of 2.197 MW was simulated, set and achieved. Evening peak clip power savings in excess of an average of 3 MW were achieved. / MIng (Mechanical Engineering), North-West University, Potchefstroom Campus, 2015

<p>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.</p> <p><br></p> <p>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.</p> <p>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 makeup  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 over consumption 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.</p> <p>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, orminimal, 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 breaksor  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 areconstant even during the production hours i.e.  the hours that there is active air consumptionby the pneumatic devices on the floor, which may not be the case due to the increased airflow 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 theremay be additional air leaks that may be created later on,  and the energy and power lostdue 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.</p> <p>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 ofthe air leaks were observed continuously and in real time.  A real time monitoring system canprovide 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 finda non intrusive 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 correlationalong with other factors has been exploited in this research to find a novel and viable methodof leak accounting to develop a Continuous Air Leak Monitoring (CALM) system.</p> <p><br></p>

L'objectif de cette thèse est la conception, dans un premier temps, des différentes stratégies de commande pour un générateur hybride composé par une pile à combustible et une source auxiliaire de stockage d'énergie. L'outil des Inégalités Linéaires Matricielles (LMI) est utilisé dans la thèse pour la solution du problème de la commande robuste et multi-variables. Dans un premier temps la commande se consacre à la gestion de la partie électrique de la pile. Des stratégies de commande sont proposées pour les convertisseurs élévateurs du bus continu mais aussi pour le contrôle d'un onduleur de tension conçu pour une opération en mode isolé du réseau. La validation d'une partie du contrôle sous un banc d'essai a été réalisée. Dans un deuxième temps, la commande de la partie fluidique de la pile a été traitée. La gestion de la dynamique de l'air en entrée de la pile est assurée par la commande du débit du compresseur. Le sous-système de compression d'air est régulé pour garantir un certain taux d'excès d'oxygène désiré, ce qui permet d'améliorer les performances de la pile. Une introduction au contrôle des systèmes à paramètres variants (LPV) est aussi présentée. Des études de robustesse des contrôleurs proposés ont été effectuées, et ces caractères robustes sont comparés avec plusieurs méthodes de commande classique, prouvant ainsi l'importance des méthodologies de commande robuste et multi-variables. / The objective of this thesis is the design of several control strategies for a hybrid power generator composed by a fuel cell and an auxiliary energy storage source. The Linear Matrix Inequalities (LMI) tools are extensively used in this dissertation as a solution to the mutivariable robust control problem. As a first approach, the control methodology is consecrated to the electrical power management sub-system of the fuel cell. Different strategies are proposed to control the hybrid boost power converter configuration for DC voltage applications. The methodology is extended to AC islanded applications considering the additional control of a voltage inverter. The validation on a dedicated test-bench, of a part of the proposed control strategies, is presented. In a second approach, the control of the air supply system is addressed. The management of the air dynamic entering the fuel cell is assured by the control of the air flow of a compressor. The air supply sub-system is controlled to keep a desired oxygen excess ratio, this allow to improve the fuel cell performance. An introduction to the control of Linear Varying Parameter (LPV) systems is also presented. Robustness analysis studies are performed, these robust properties are contrasted with several classic control strategies, demonstrating the advantage and the importance of multivariable robust methodologies.

Power dispersion within oil injected screw air compressors : The PhD-work shows the power dispersion within the oil- and air circuits of oil injected screw air compressors for the working pressures (Pd), where Pd has been tested for Pd ≤ 8,5 bar (a) and Pd ≤14,0 bar(a) respectively. The executed test runs with mineral oil have further confirmed the suppliers quoted performance data within stated tolerances. For comparison of the compressor performance with type of lubricant, the performance tests have been repeated with the four most common types of lubricants, which today are commercialised for screw air compressors. The selected lubricants hold the same cinematic viscosity (ISO VG 46), but the lubricants diverge in question of solubility of air and in formation of air bubbles during the compression cycle. These phenomenas confirm deviations in prevailing viscosity in the oil film and demonstrate that the performance data vary slightly with selected type of lubricant. The tests have proven that the air, which dissolve in the lubricant during the compression cycle will not degas during the resting period in the air/oil receiver, nor will the miniscule air bubbles degas due to their low ascending speed. This means that the content of dissolved air and air bubbles in the oil in the receiver becomes the most elevated within the system and where the temperature is the highest within the compressor cycle. Further is the resting period of the oil in the receiver extreme long in relation to the over all operating cycle of the oil. The conclusion is that the destruction (oxidation) of the oil is taking place in the oil/air receiver and nowhere else within the system. To counteract the oxidation and other destructive processes in the oil circuit « additives » are introduced in the oil. So are e.g. anti-oxide additives reducing the formation of peroxides and are by this reducing the oxidation velocity of the oil until the additives have been consumed. These additives are reducing the oxidation velocity of the lubricants, but will as well, due to the increased polarity caused by the additives, increase the content of dissolved water in the oil. However, this increased content of dissolved water is (strongly) reducing life of the roller bearings. The measured quantities of dissolved water in the lubricants (after the executed tests) have been compared with achieved bearing life from tests executed by others. The PhD work is finally summarizing that the only method to strongly reduce the destruction of the lubricant is to immediately separate off the oil from the compressed air at exit of the compressor. In addition, the today's « dumped » power in the oil cooler can be recovered to increase the available pneumatic power by some 25-30%. Assumingly, this increase in working temperature of the pneumatic air will, in addition increase the efficiency in applied pneumatic tools.

Ett ljudfenomen som uppstår i samband med luftkomprimeringen i den nya D7 motorn har uppmärksammats som ett problem av kunderna. Ljudfenomenet som resonerar i hytten bidrar till en obehaglig arbetsmiljö. Uppdraget har i sin tur varit att utveckla en luftkompressormonterad ljuddämpare mot en kravspecifikation som eliminerar detta fenomen. Med hjälp av diverse verktyg och en spiral produktutvecklingsprocess utfördes ett flertal iterationer av dem koncept som kan tänkas lösa problemet. Dessa iterationer konstruerades i mjukvaran CATIA V5 för att sedan beställas in som fysiska prototyper i materialet Pa12. För att bekräfta prototypernas funktionalitet utfördes simuleringar samt fysiska tester. Det resulterande arbetet blev ett konceptförslag till Scania CV AB som uppfyller kravspecifikationerna. Lösningens ljuddämpningsförmågan reducerade ljudfenomenet med 73% i genomsnitt. Med hjälp av observationer och analyser under de fysiska testgenomförandet uppmärksammades komplikationer som bör åtgärdas. Det mest kritiska med det nuvarande konceptet är dem vibrationer som uppstår. För att åtgärda detta problem kommer det krävas ytterligare infästningspunkter på motsvarande sida till de nuvarande. All mätdata i denna rapport är modifierat. Detta för att skydda känslig information. / A noise phenomenon that arises in connection with air compression in the new D7 engine has been noted as a problem by the customers. The sound phenomenon resonates in the cabin contributes to an unpleasant work environment. The mission, in turn, has been to develop an air compressor-mounted silencer against a requirement specification to eliminate this phenomenon. Using various tools and a spiral product development process, a number of iterations were made of those concepts that could solve the problem. These iterations were engineered in the CATIA V5 software, then ordered as physical prototypes in the material Pa12. To confirm the prototypes' functionality, simulations and physical tests were performed. The resulting work became a concept proposal for Scania CV AB that meets the requirements specifications. The solution managed to reduce the sound phenomenon by 73% on average. With the help of observations and analyzes during the physical test implementation, complications were noted that should be addressed. The most critical on the current concept is the vibration that occurs. To fix this problem additional attachment points will be required on the corresponding side to the current ones. All data in this report have been modified. This is to protect sensitive information.