EAGER: Multiphase Flow and Heat Transfer for isothermal Compressed Air Energy Storage

国家电网中可再生能源的增加导致风能的快速增长。然而，间歇性问题（风并不总是吹）是一个关键的挑战。发展经济、长寿命、公用事业规模的储能系统对我国乃至世界都具有重要意义。虽然压缩空气储能可以实现这些公用事业规模的长期使用，但在效率方面仍然存在关键挑战。为了解决这些问题，需要对高压比下等温压缩和膨胀效率的控制参数和物理特性有基本的了解。拟议的研究项目将通过确定控制与全尺寸系统相关的往返效率的关键参数和热流体物理特性，实现等温压缩空气储能。传播的研究结果可用于指导该技术的开发，以实现有效的长时间风能存储，这可以确保美国电网的弹性和深度脱碳，从而增强我们国家的能源安全和独立。此外，该项目支持研究生在可再生能源方面的研究，同时促进多样性和包容性。该项目的目标是确定和表征控制高效等温压缩空气能量储存的多相流和传热因素的主要基础。特别是，拟议的工作将采用光学可访问的压缩和膨胀实验装置，允许高达50:1的压力比来识别相关的多相流和传热物理。此外，这项为期一年的高度集中的实验工作将根据关键的无量纲参数表征等温往返效率。该项目旨在：1)通过实验验证新开发的Crowe数和热交换器质量负荷是表征等温效率的主要无量纲数字的假设；2)通过实验证明高往返存储效率可以在高压比（约50:1）下实现；3)确定对这种类型的能量存储效率至关重要的关键多相流和传热物理。这项新研究对等温压缩空气储能技术的发展具有革命性意义，可以帮助解决风能间歇性问题，从而使国家实现深度脱碳电网。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Increasing renewable energy in the nation’s power grid is leading to rapid growth in wind energy. However, intermittency issues (the wind doesn't always blow) is a critical challenge. Development of economical, long-duration, utility-scale storage is important for our nation and world. While compressed air energy storage allows these utility-scale long-duration aspects, key challenges remain in terms of efficiency. To solve these, a fundamental understanding of the controlling parameters and physics for isothermal compression and expansion efficiency at high pressure ratios is needed. The proposed research project will enable isothermal compressed air energy storage by identifying the key parameters and thermo-fluid physics that control round-trip efficiencies relevant to full-scale systems. The disseminated findings can be used to direct development of this technology for effective long-duration wind energy storage, which can ensure a resilient and deeply decarbonized US power grid that enhances our nation's energy security and independence. In addition, this project supports graduate student research in renewable energy while fostering diversity and inclusion.The goal of this project is to identify and characterize the primary underpinning multiphase flow and heat transfer factors that control efficient isothermal compressed air energy storage. In particular, the proposed work will employ an optically accessible experimental setup for both compression and expansion that allows pressure ratios of up to 50:1 to identify relevant multiphase flow and heat transfer physics. In addition, this one-year highly focused experimental effort will characterize isothermal round-trip efficiency in terms of the key non-dimensional parameters. The project aims, for the first time, to: 1) experimentally test the hypothesis that the newly developed Crowe number and heat exchanger mass loading are the primary non-dimensional numbers that characterize isothermal efficiency, 2) experimentally demonstrate that high round-trip storage efficiency can be achieved at high pressure ratios (ca. 50:1), and 3) identify the key multiphase flow and heat transfer physics that are critical to efficacy of this type of energy storage. This new research can be transformative for isothermal compressed air energy storage technology development, which can help solve the wind energy intermittency issues in order to allow the nation to achieve a deeply decarbonized grid.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.