Energy and exergy analysis of compressed air engine systems
TL;DR: In this article, three-stage and four-stage compressed air engine systems are optimized by analyzing the energy and exergy distribution from a technological viewpoint, and their characteristics are compared in terms of shaft work, coolth, overall efficiency, and ex-ergy distribution.
About: This article is published in Energy Reports.The article was published on 2021-11-01 and is currently open access. It has received 6 citations till now. The article focuses on the topics: Compressed air & Exergy.
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TL;DR: In this paper , a series of experiments were conducted to investigate the effect of key parameters on the power performance, economy and energy conversion efficiency of CAV. And the authors presented an investigation of the power system with parallel operation mode based on experiments to improve power performance of PM.
Abstract: Power performance of pneumatic motor (PM) limits its application in compressed air vehicle (CAV) as an auxiliary power. This study presents an investigation of the power system with parallel operation mode based on experiments to improve the power performance of PM. First, the test bench of PM in parallel operation mode is built. Then, a series of experiments are conducted to investigate the effect of key parameters on the power performance, economy and energy conversion efficiency of CAV. The interaction among the key parameters of the PM and the influence of them on the power performance are discussed. Subsequently, the power performance, economy and energy conversion efficiency of the PM working in single and parallel operation modes are compared. Experimental results show that the maximum power output of the PM is 979 W, and the energy conversion efficiency of PMs 1 and 2 are 6.54% and 6.80% when the PM works in parallel operation mode. The parallel operation mode of PM can improve the power performance, economy and energy conversion efficiency of CAV.
2 citations
TL;DR: In this paper , a pneumatic motor test bench is built and tested under different inlet pressures, operation modes, and three driving cycles, and the results show that with an increase in rotation speed, the output power and efficiency first increase and then decrease, and compression air consumption rate decreases.
Abstract: An air-powered vehicle is a low-cost method to achieve low-pollution transportation, and compressed air engines (CAE) have become a research hotspot for their compact structure, low consumption, and wide working conditions. In this study, a pneumatic motor (PM) test bench is built and tested under different inlet pressures, operation modes, and three driving cycles. On the basis of the data obtained by sensors, power output, compressed air consumption rate, and efficiency are calculated to evaluate the pneumatic motor performances. The results show that with an increase in rotation speed, the output power and efficiency first increase and then decrease, and the compression air consumption rate decreases. With an increase in torque, the rotation speed decreases, and the power output and efficiency first increase and then decrease. With an increase in mass flow rate, the torque increases, the power output and efficiency first increase and then decrease. The pneumatic motor achieves the best performance under a rotation speed of 800–1200 rpm, where power output, efficiency, and compressed air consumption rates are 1498 W, 13.6%, and 10 J/g, respectively. The pneumatic motor achieves the best power output and efficiency under the UDDS driving cycle.
TL;DR: In this article , the authors used an Arduino Mega 2560 and ESP32-WROOM microcontroller to control the valve timing with the rotational input signal obtained from an absolute encoder.
Abstract: An electronic valve timing control unit has been developed mainly for the internal combustion engine operation. This study aims to implement a similar technology into a single-piston expander (SPE) with readily available and low-cost microcontrollers. The study used an Arduino Mega 2560 and ESP32-WROOM microcontrollers to control the valve timing with the rotational input signal obtained from an absolute encoder. The SPE has been expected to run at the rotational speed of up to 2000 rpm. This setup was prepared to simulate the actual SPE operation using a direct current motor to drive the spindle connected to the encoder shaft to create a similar hardware testing and controlled environment. The study aims to identify the efficiency of the microcontroller’s performance with a variation of the valve’s opening and closing time. Results have shown that the clock rate of the microcontroller affects the performance of valve timing response. By increasing the clock rate, the microcontroller can control the valve at a higher speed.
TL;DR: In this paper , the performance evaluation of a low capacity pneumatic engine is shown, through modeling and simulation in order to identify the feasibility of its application in commercial vehicles for short distances.
Abstract: In the present work, the performance evaluation of a low capacity pneumatic engine is shown, through modeling and simulation in order to identify the feasibility of its application in commercial vehicles for short distances. For the modeling of the pneumatic engine, a comprehensive approach has been used that includes the compressed air supply pipe, the cylinder compression - expansion chamber, and the intake and exhaust valves. The compressed air supply system is modeled using compressible fluid flow models. The fluid flow is considered adiabatic represented by the model known as Fanno flow (or non-isentropic) and it is assumed to be in a steady state. The flow in the opening and exhaust valves are evaluated as adiabatic and isentropic fluid, using a divergent - convergent compressible fluid model. The simulation results show that the feeding pressure and the pipe diameter have a great influence on the motor power. Also, the compression ratio has been found to have strong influence on the overall system efficiency. On the other hand, the simulations show that the initial pressure of the piston does not have a great influence on performance indicators, such as power or efficiency. However, from the results found in this work, it can be seen that the model and all the results obtained in this work can be used to design and generate an optimization model that describes a pneumatic engine proposed for commercial vehicles of low capacity and short distances.
References
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3,356 citations
TL;DR: In this paper, a review of electrical energy storage technologies for stationary applications is presented, with particular attention paid to pumped hydroelectric storage, compressed air energy storage, battery, flow battery, fuel cell, solar fuel, superconducting magnetic energy storage and thermal energy storage.
Abstract: Electrical energy storage technologies for stationary applications are reviewed. Particular attention is paid to pumped hydroelectric storage, compressed air energy storage, battery, flow battery, fuel cell, solar fuel, superconducting magnetic energy storage, flywheel, capacitor/supercapacitor, and thermal energy storage. Comparison is made among these technologies in terms of technical characteristics, applications and deployment status.
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