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Compressed air usage, storage, leakage, and efficiency are several factors that influence the efficiency of a compressed air system. Usually for those industrial plants having multiple types and sizes of air compressors, the efficiency of each one is quite different, even for those of the same type and size. It greatly influences overall system per...
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... Compressed air usage, storage, leakage, and efficiency are several factors that influence the efficiency of a compressed air system. Usually for those industrial plants having multiple types and sizes of air com- pressors, the efficiency of each one is quite different, even for those of the same type and size. It greatly influences overall system performance when demand is matched with the air compressor or group operated at or near maximum efficiency levels. One industrial plant was chosen in this article to illustrate this process. The trended data were analyzed to obtain the efficiency for each individual air compressor and the mix of several air compressors. The result showed that annual energy savings of 15 to 50 percent can be achieved for a whole year using an optimized operation schedule. INTRODUCTION Compressed air systems are widely employed in industrial plants to produce the compressed air vital to everyday facility operations. Since air compressors consume a greater amount of electricity than any other type of facility equipment[1], an optimized and effectively operated air compressor system is essential for creating energy savings. Usually many approaches can be employed to improve a com- pressed air system’s efficiency. Van Ormer[2] and Foss[3] summarized these approaches: • Minimize the energy lost through distribution, • Reduce system air waste such as air leaks and excess pressure loss, • Optimize the demand side by minimizing optimum flow and pres- sure required, and • Select the best energy efficient compressor. Sheckler[4] presented a case study of improving efficiency for com- pressed air systems. He assessed the old system of a metal wire manu- facture and proposed a new one with retrofit of a new VFD air compres- sor and two new air dry receivers. The new system efficiency was at least 14.7 percent higher than the old system. Reducing air leakage in the distribution network is another key to savings. Based on data from Sheckler[4] (2007), the new system, combined with eliminating leakage, created almost 60 percent savings for the plant in a year. Dalgleish and Grobler[5] performed an energy audit on a packaging facility. Fifty-five percent of the annual electricity used for compressed air production was saved by lowering the system pressure setpoint, repairing air leaks, and reducing unnecessary compressed air use. This article focused mainly on how to optimize operation of an industrial compressed air system, with multiple air compressors usu- ally employed to satisfy peak demand, meet different circumstance re- quirements, and serve as backup during maintenance. Air compressors usually show different performance—even those of the same model and size. Seldom do all compressors run simultaneously. When inte- grated into a system, the most efficient individual air compressor or group of compressors has the greatest influence on overall system per- formance. Though operators manage the operation of the air compres- sors, seldom do they know when to run which, to achieve greater effi- ciency. In this article, one industrial plant had been chosen to illustrate this process, assuming that the air leakage in the distribution line was eliminated. SYSTEM INFORMATION FOR THE SELECTED SITE The compressed air system involved in this study ran 24 hours a day, 7 days a week. It was comprised of seven air compressors, a com- pressed air receiver, and two compressed air dryers. The compressed air was mainly used for industrial production and pneumatic control. Figure 1 is a schematic diagram of this system. Table 1 gives the system ...
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Citations
... Many other factors influence the efficiency of a CAS. A research found that having proper maintenance of any system will lead to the reliability and longevity of the system [29]. Another way to decrease compressed air usage is to use a colder outdoor air supply for air compressors [30]. ...
Energy audits directly provided the industrial sector with reduced energy costs and avoided emissions. Still, they also lead to far-reaching indirect and induced local, regional, and national benefits. This paper aims to present the techno-economic-environmental analysis to achieve decarbonization through implementing industrial energy efficiency at micro and macro levels. An integrated techno-economic-environmental methodology is developed. Case studies of micro-level carbon reduction efforts through industrial energy efficiency technologies are presented. The broader macroeconomic and environmental effects of technology on society are analyzed using data from 206 energy audits of industrial compressed air systems conducted over 13 years. The impacts show that energy-efficient improvements lead to direct cost savings for manufacturers, boost economic activity across sectors, and affect carbon dioxide emissions both short-term and long-term in the region. Given their extensive benefits, energy audits significantly influence policymaking. We devised a methodology to link micro-level energy audit data with macroeconomic and environmental analyses to quantify these cascading benefits. The economic scenario analysis shows that $228 M has been saved from direct industrial energy savings from implementing all compressed air recommendations in the studied periods and the region. In addition, the investment made through manufacturers would create 2,025 jobs and $383 M annually, cascading regional economic impacts. The environmental analysis shows that the regional manufacturers have directly avoided about 2.8 M metric tons of carbon dioxide emissions.
... The compressor unit is then switched to active mode to provide air to the storage and distribution units. This process was repeated periodically in a related study (Zhang et al., 2013). The degradation of the storage and distribution units causes air leakage, causing the pressure to drop faster than that observed in the normal state, which in turn increases the working frequency of the compressor unit, that is, increases its working time. ...
In this study, an opportunistic predictive maintenance framework was developed for a system comprising one continuous operation component (COC) and intermittent operation component (IOC). The COC operates consistently with the system. In contrast, the IOC operates alternately in operation and standby modes. The degradation of the COC can increase the working frequency of the IOC, which can accelerate its degradation process. Omitting this degradation interaction in degradation modeling and reliability assessment could result in inaccurate lifetime prognostic and suboptimal maintenance plans. Therefore, in this study, a degradation model for the IOC is proposed considering the influence of the degradation state of the COC. A reliability model for the IOC was derived and used for predictive maintenance. Based on the proposed degradation models, an opportunistic predictive maintenance policy was proposed, considering the structural and economic dependencies between the components. Finally, a case study of an air compressor system is conducted to demonstrate the viability and benefits of the proposed model.
... Since air compressors consume more electrical energy than any other type of facility equipment [1], an optimized and efficient compressed air system is essential to achieve energy savings. There are usually multiple approaches to improve the performance of a compressed air system. ...
Compressed air systems are commonly used in industrial plants to produce the compressed air required for the facility's daily operations. Since air compressors consume more electricity than any other type of facility equipment, an optimization of the efficiency of compressed air system operation cycles is essential for energy savings. In this article the demand for compressed air in production plants with different operating characteristics is analyzed. It is checked how the neural network identified for a given plant would work in the case of another plant with a different needs while predicting compressed air demand, which is understood as a prediction of compressor on/offs. The simulation results based on real data indicate possible decisions that improves system efficiency.
... Even if the user's air usage fluctuates, this device can maintain consistent pressure. This is done by regulating the rotational speed of the motor by installing an inverter, which led to significant energy savings by not operating the compressor at a greater compression level than necessary [29]. ...
This review accumulates information from various research works about the preferable manufacturing process, process parameters, parts of the compressor, working principle, material, and critical issues with some of the solutions that might be possible in the era of future industry. In addition, some work is also done on the tribological trends in the compressor. In this paper, detailed information has been gathered about the compressor parts and their working principle. A detailed analysis has been done on the material used to manufacture the compressor. Some details have been shared about preventing the loss to the compressor when it is in the application mode. As per this paper, PTFE/MoS2, FC, PEEK/Ceramic materials, mica-filled tetrafluoroethylene are advanced materials used for the compressor. Protective layers can be made on the parts to prevent some functional loss. Numerous studies have brought about great advancements in compressor performance, but many remain to be discovered. With n-TiO2 and n-MnO2, ZDDP (zinc disulfide) should be increased for antifriction properties. Some research has proven that CO 2 can improve the tribological performance of two interacting surfaces by forming a lubricating carbonate layer that reduces friction and wears. New lubricating oils are showing promising results, but with the gradual depletion of natural oil resources, efforts have to be made to make various oils obtained from sources other than oil reserves or petroleum. A completely oil-free compressor with no lubrication in the crankcase and no lubrication in the other components dry oil-free air supply may be accomplished by employing various oil-less compressor technologies such as scroll water-injected screw, two-stage dry screw, and so on. In the 21st century, it aims to maximize energy savings from air compressors. It is critical to operating at a compression level that matches the amount of air consumption (optimal volume) and to avoid operating at a compression level that is greater than necessary. The conclusion can be obtained that understanding for the compressor will be established, and some tribological issues will be solved with new technology and material.
... Eret et al. [10] explained this approach with a model called an end-user catalogue. Zhang et al. [11] investigated compressors of various types and sizes and their respective efficiencies in an industrial facility. The electrical energy they consumed, the amount of CA produced, and the inlet temperatures of these systems were measured, and it was found that compressors yielded higher efficiency under higher loads. ...
The electricity consumption of compressed air (CA) production and utilisation systems is high, due to an absence of suitable recovery methods and proper measurements in most industrial plants. This situation results in high costs of production and reduced profits. In our study, we therefore investigate the energy-saving potential of a CA system with the aim of reducing electricity consumption in an industrial facility. Our study consists of two parts: in the first stage, we evaluate the applicability of methods such as elimination of leakage in distribution lines, loaded-unloaded operation of compressors, and the use of waste heat recovery system methods, both physically and economically, while in the second, we examine the correlations between leakage airflow rate, noise, and system pressure in a general CA system and carry out regression analyses, using the SPSS (Statistical Package for Social Sciences) software program, for the first time. Our results suggest that optimised and improved CA systems are energy-saving solutions when applied in industrial plants. We demonstrate that there are strong correlations between the system pressure, air leakage diameter, noise, and annual leakage cost in industrial CA systems. The relationships between these variables can be expressed as a power model (Y = β × Xⁿ).
... This leads to both the increased costs of the investment itself, which is the installation of a compressed air network, but also increases the costs of maintenance and energy [1,2,3]. There is not much information available in the literature on the 5,6]. An indicative distribution of the operating costs of the air compressor is shown in Figure 1. ...
Compressed air is a very widely used energy medium, used in various fields. Is one of the most widespread, but also one of the most expensive working media used in modern industry. According to studies available in the literature in Australia and the European Union, energy consumption by compressed air systems accounts for about 10% of total industrial energy consumption, while in the United States it accounts for 30% of total electricity consumption. In addition, these systems are one of the least efficient forms of energy - only about 10-30% of the energy generated by the compressor reaches the end point. This is primarily due to a change in the form of energy (e.g. heat), but also leaks in the network and inefficient use. During operation in the compressed air network, pressure losses (linear and local) occur as a result of pipeline construction as well as pressure losses caused by the use of devices and elements responsible for maintaining adequate air quality (local losses) in the network. The pressure drop caused by the pipeline elements will depend on the extent of the network, the diameter of the pipeline, the number of places where there is a change in the direction of air flow (elbows, venturi, etc.). However, the losses caused by the use of treatment elements will depend on the expected air quality (number of filtration stages, appropriate air dryer) as well as on the network operation time (e.g. air filter contamination). The purpose of this study is to determine the impact of compressed air network extensions on energy losses resulting from, among others friction during flow. The values of these losses depend on many parameters such as efficiency, air flow speed, diameter and length of the pipeline. Knowledge about the correlation of these parameters will allow for proper selection of compression devices, as well as for optimal design of the pneumatic network.
... In chemical processes, dynamic optimization frequently deals with distributing global service demands of the plant into individual targets assigned to each member of a group of service equipment, while minimizing a predetermined generalized cost. Typical service equipment (or utilities) include sets of boilers/steam generators, heatexchangers, pumps, air-compressors, and the like (Bujak, 2009;Collins and Lang, 1998;Muller and Craig, 2014;Teles et al., 2008;Zhang et al., 2013). In what follows, the individual components from the 'group' under consideration will be referred to as 'units'. ...
A new dynamic optimization strategy is substantiated for allocating demands, in a typical process plant, to a set of service equipment working in parallel. It is a stochastic process in nature, but its optimal control is based on the solution to a related deterministic optimal tracking problem to minimize a quadratic cost objective restricted by linear dynamics. The main theoretical novelty, demonstrated here, is the separation theorem for the stochastic tracking problem. This means: the desired optimal stochastic solution can be calculated from the solution to the deterministic problem, by replacing the state variable with their optimal estimates, which can be generated online following a Kalman filter scheme. The set-points assigned to each conventional controlled device are allowed to be continuously changed while: (i) minimizing a combined cost, which is cumulative in time and takes into account the dynamics of all the individual utilities, and (ii) generating a feedback law that can cope with general disturbances, like changes in fuel composition and with noisy measurements, i.e. with differences between the predicted and the measured values of the variables.
