In memory of Sir David John Cameron MacKay FRS FInstP FICE (22 April 1967 – 14 April 2016). David was passionate about sustainable energy. One key element for sustainable energy is energy storage. As a small tribute, this article presents a review from a physics perspective of the thermodynamics of compressed air energy storage. Firstly, I treat adiabatic compressed air energy storage, where the heat of compression of the air is kept in the compressed air. Then I discuss improvements that can be made by combining compressed air energy storage with external heat stores. Next, I address isothermal compressed air energy storage, where the temperature is allowed to equilibrate with the environment. In each case, I consider two scenarios: underground caverns and underwater airbags. Finally, I address the case where the air is compressed and cooled so much that it liquifies. Throughout, I explain that the real point is to store available work, called exergy in the engineering community, rather than energy. Although my treatment is mostly from the ideal point of view of quasistatic processes, I give some pointers to technological implementations of the various methods and to some references on their thermodynamic efficiencies.

中文翻译：

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可持续能源储存——使用热空气、冷空气或液态空气

纪念大卫·约翰·卡梅伦·麦凯爵士 FRS FINstP FICE（1967 年 4 月 22 日至 2016 年 4 月 14 日）。大卫对可持续能源充满热情。可持续能源的一个关键要素是能量储存。作为一个小小的致敬，本文从物理角度对压缩空气储能的热力学进行了回顾。首先，我处理绝热压缩空气储能，其中空气的压缩热保留在压缩空气中。然后我讨论了通过将压缩空气能量存储与外部热存储相结合可以实现的改进。接下来，我将讨论等温压缩空气能量存储，其中允许温度与环境平衡。在每种情况下，我都会考虑两种情况：地下洞穴和水下安全气囊。最后，我解决了空气被压缩和冷却到液化的情况。在整个过程中，我解释说真正的重点是存储可用的工作，在工程界称为火用，而不是能量。尽管我的处理主要是从准静态过程的理想观点出发，但我还是提供了一些关于各种方法的技术实现的指针，以及一些关于它们的热力学效率的参考资料。