Ren Teng, Xu Weiqing, Jia Guan-Wei, Cai Maolin
School of Automation Science and Electrical Engineering, Beihang University, Beijing 100191, China.
Pneumatic and Thermodynamic Energy Storage and Supply Beijing Key Laboratory, Beijing 100191, China.
Entropy (Basel). 2020 Sep 11;22(9):1015. doi: 10.3390/e22091015.
Reducing carbon emissions is an urgent problem around the world while facing the energy and environmental crises. Whatever progress has been made in renewable energy research, efforts made to energy-saving technology is always necessary. The energy consumption from fluid power systems of industrial processes is considerable, especially for pneumatic systems. A novel isothermal compression method was proposed to lower the energy consumption of compressors. A porous medium was introduced to compose an isothermal piston. The porous medium was located beneath a conventional piston, and gradually immerged into the liquid during compression. The compression heat was absorbed by the porous medium, and finally conducted with the liquid at the chamber bottom. The heat transfer can be significantly enhanced due to the large surface area of the porous medium. As the liquid has a large heat capacity, the liquid temperature can maintain constant through circulation outside. This create near-isothermal compression, which minimizes energy loss in the form of heat, which cannot be recovered. There will be mass loss of the air due to dissolution and leakage. Therefore, the dissolution and leakage amount of gas are compensated for in this method. Gas is dissolved into liquid with the pressure increasing, which leads to mass loss of the gas. With a pressure ratio of 4:1 and a rotational speed of 100 rpm, the isothermal piston decreased the energy consumption by 45% over the conventional reciprocation piston. This gain was accomplished by increasing the heat transfer during the gas compression by increasing the surface area to volume ratio in the compression chamber. Frictional forces between the porous medium and liquid was presented. Work to overcome the frictional forces is negligible (0.21% of the total compression work) under the current operating condition.
在面临能源和环境危机的情况下，减少碳排放是全球紧迫的问题。无论可再生能源研究取得了何种进展，致力于节能技术的努力总是必要的。工业过程中流体动力系统的能源消耗相当可观，尤其是气动系统。提出了一种新颖的等温压缩方法来降低压缩机的能耗。引入了一种多孔介质来构成等温活塞。该多孔介质位于传统活塞下方，并在压缩过程中逐渐浸入液体中。压缩热被多孔介质吸收，最终与腔室底部的液体进行热传导。由于多孔介质的表面积大，热传递可显著增强。由于液体具有大的热容量，液体温度可通过外部循环保持恒定。这创造了近等温压缩，使以热的形式损失且无法回收的能量最小化。由于溶解和泄漏，空气会有质量损失。因此，该方法对气体的溶解和泄漏量进行了补偿。随着压力增加，气体溶解到液体中，导致气体质量损失。在压力比为4:1和转速为100转/分钟的情况下，等温活塞比传统往复活塞降低了45%的能耗。这种节能是通过增加压缩室内的表面积与体积比来增强气体压缩过程中的热传递实现的。给出了多孔介质与液体之间的摩擦力。在当前运行条件下，克服摩擦力所需的功可忽略不计（占总压缩功的0.21%）。
