Feasibility Study of Optimisation of Scroll Air Motors and Energy Recovery from Exhaust Compressed Air

虽然可再生资源是巨大的，但用所有的可再生能源来满足我们的电力需求似乎有些牵强。可再生能源，如太阳能和风能，是分散和间歇性的。因此，能量储存对于获得稳定的电力供应至关重要。压缩空气储能是一种众所周知的可控和负担得起的方法。储存在压缩空气中的能量将在需要时用于发电。然而，常用的空气马达（空气变压器）是一种具有成本效益的传统叶片式空气马达，但叶片式空气马达的能源效率相当低，不到30%。这是在可再生能源供电中采用压缩空气储能系统的一大缺点。气动执行器通过运动技术在一系列应用中提供解决方案。在英国，大量的能源，超过10%的国家电网输出，被用来产生压缩空气。此外，供应给制造商/工厂的电力中约有20%用于产生压缩空气。然而，气动执行器系统的能源效率仍然很低。在欧洲国家，工作系统的能源效率在23%-30%之间。分析认为，造成这种低能效的主要原因是气动执行机构的开路结构。尽管已经做了很多努力，但人们认为没有合适的机制来回收通过废气损失的能量。因此，在废气再利用这一课题上有相当大的研究空间。涡旋气动马达是气动执行器的一个相对较新的概念。其独特的结构特点是比传统气动执行机构具有更高的能量转换能力。涡旋技术目前主要应用于空调和制冷压缩机。最近，这个概念被重新发明，以建立涡旋空气马达，这是立即采用驱动发电机发电。它们已被许多公司成功地应用于微型热电联产系统，如Energetix Group Plc、Honda和Climate Energy。涡旋式空气马达为回收排气处的能量损失和有效地为可再生能源发电提供了一种可能合适的执行器。涡旋气动马达作为一种新型的节能气动执行机构，有望在不久的将来得到广泛的工业和民用应用。然而，在这一领域取得实质性进展之前，需要解决一些基本问题。本提案旨在寻求EPSRC的支持，建立数学家和工程师之间的联系，以进行解决与卷轴结构及其应用相关的一些基本问题的可行性研究。本课题的任务是：-基于现有卷轴结构，开发完整的卷轴数学模型，并在Matlab/Simulink中编写软件程序；-在伯明翰的实验室建立一个新的系统，回收气动执行机构排出的空气，以提高能源效率；-研究涡旋空气马达在低压、可变空气流量的压缩空气供应下工作时的动态行为；-调查下游的回收设备如何影响气动执行器的性能；-研究可行的控制策略，以便在流量不确定的压缩空气供应变压力下产生稳定的电力；-使用微分几何方法研究不同形状的卷轴，从而提高能源效率；-通过建模和仿真研究优化，研究设计参数如何影响涡旋气动马达的能效；-验证数学模型和仿真结果。

Although renewable resources are immense, it seems far-fetched to use all the renewable supply to satisfy our power requirement. The renewable sources, such as solar and wind power, are diffuse and intermittent. So energy storage is very important for obtaining a stable power supply. Compressed air energy storage is a well known controllable and affordable approach nowadays. The energy stored in compressed air will be used to generate electricity when required. However, the commonly used air motor (air transformer) is a cost effective traditional vane type air motor but the energy efficiency of vane type air motors is rather low, less than 30%. This is a big drawback in adopting compressed air energy storage system in the renewable resources power supply. Pneumatic actuators provide solutions through motion technology in a range of applications. In the UK, a massive amount of energy, over 10% of the National Grid output, is used to generate compressed air. Also, around 20% of electricity supplied to manufacturers/factories has been employed to generate compressed air. However, the energy efficiency of pneumatic actuator systems remains low. In European countries, an energy efficiency of between 23%-30% is achieved in working systems. It is considered that such low energy efficiencies are mainly due to the open-circuit structure of pneumatic actuator systems. Although much effort has been made, it is considered that there are no suitable mechanisms to recover energy lost through the exhaust. Therefore, there is considerable scope for research in the subject of reusing the exhaust air. A scroll air motor is a relatively new concept to pneumatic actuators. Its unique structure features its higher ability of energy conversion than conventional pneumatic actuators. The scroll technique is now mainly implemented in air conditioner and refrigeration compressors. Recently, the concept was re-invented to build scroll air motors, which are immediately adopted to drive generators for electric power generation. They have been successfully used in Micro Combined Heat and Power systems by a number of companies, such as Energetix Group Plc, Honda and Climate Energy. Scroll type air motors provide a possibly suitable actuator for recovering the energy loss at the exhaust and generating electricity efficiently for renewable power sources. It is anticipated that scroll air motors as a new type of energy efficient pneumatic actuator will be found in wide industrial and domestic applications in the near future. However, a number of fundamental problems need to be addressed before substantial progresses can be made in this area. This proposal is to seek the EPSRC support to set up a link between mathematicians and engineers to conduct the feasibility study of solving a number of fundamental issues associated with the structure of scrolls and their applications. The tasks of the project are:- to develop a complete mathematical model of scrolls based on the current scroll structure and a software program in Matlab/Simulink;- to set up a novel system to recycle pneumatic actuator exhaust air to improve energy efficiency in the laboratory at Birmingham;- to investigate the dynamic behaviour of scroll air motors while they are working at a low pressure of compressed air supply with variable air flow rates;- to investigate how the recycling equipment at down stream affects the behaviour of the pneumatic actuators;- to investigate a feasible control strategy for generating a stable electrical power at a variable pressure of compressed air supply with uncertain flow rates;- to investigate different shapes of scrolls which will lead to high energy efficiency using a differential geometry method;- to investigate how the design parameters affect the energy efficiency of scroll air motors through madelling and simulation study - optimisation;- to verify mathematical model and simulation results.