Investigation into an ultra-high efficiency liquid-piston compressor

超高效率液体活塞压缩机的研究

• 批准号: 2109784
• 金额: --
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2018
• 资助国家: 英国
• 起止时间: 2018 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2109784
• 关键词: Investigation; into; ultra; efficiency; liquid

Gas compression and expansion for the purposes of energy storage must necessarily be very high efficiency. In the case of compressed air energy storage, the round-trip efficiency of the storage cycle is limited to c times e. If both compression and expansion machines had efficiencies of 90%, then the round-trip efficiency would definitely be below 81%. For energy storage involving pumped heat, the round-trip efficiency is much more sensitive to losses in the compression and expansion processes. Typically for pumped-heat applications, the ratio of "hot" to "cold" temperatures is 2.5 (i.e. 5/2). In that case, for every 3J of net exergy passed into storage 5J of work is done in a compressor and 2J of work is recovered from an expander. The converse is true during energy recovery from storage: 5J of work is recovered from the expander while 2J of work is put into the compressor. Overall, for a pumped thermal energy storage system like this, if the machinery is 99% efficient (i.e. losses are 1%), then the losses during charging are 2.333% and losses during discharging are also 2.333% so total round-trip losses are around 4.666%. This project will explore the development of an ultra-high efficiency compressor exploiting liquid-piston technology. The most important loss mechanisms present in an existing design will be identified and a revised design will be put forward that retains the attractions of the original design but achieves higher performance. Sources of loss include: (a) heat transfer between gas and compressor components, (b) pressure-drops across valves and pipe-work, (c) heat transfer within the body of the machine itself, (d) friction losses in the displacer part of the machine, (e) oil leakage losses past the pistons of the displacer and between the different body chambers of the compressor and (f) viscous losses associated with oil motions.

用于能量存储目的的气体压缩和膨胀必须是非常高的效率。在压缩空气能量存储的情况下，存储循环的往返效率被限制为c乘以e。如果压缩机和膨胀机的效率都是90%，那么往返效率肯定会低于81%。对于涉及泵送热量的能量存储，往返效率对压缩和膨胀过程中的损失更加敏感。通常对于泵送热应用，“热”与“冷”温度的比率为2.5（即5/2）。在这种情况下，每3 J的净有效能传递到存储器中，5 J的功在压缩机中完成，2 J的功从膨胀机中回收。在从存储中回收能量的过程中，情况正好相反：从膨胀机回收5 J的功，而将2 J的功输入压缩机。总的来说，对于这样的泵送式热能储存系统，如果机器效率为99%（即损失为1%），则充电期间的损失为2.333%，放电期间的损失也为2.333%，因此总往返损失约为4.666%。本项目将探索利用液体活塞技术开发超高效压缩机。将确定现有设计中最重要的损失机制，并提出修改后的设计，保留原始设计的吸引力，但实现更高的性能。损失来源包括：（a）气体和压缩机部件之间的热传递，（B）通过阀和管道系统的压降，（c）机器本身的主体内的热传递，（d）机器的置换器部分中的摩擦损失，（e）通过置换器的活塞和压缩机的不同主体腔室之间的油泄漏损失，以及（f）与油运动相关的粘性损失。