Environmentally Sound: High Performance, Compact Thermoacoustic Refrigeration

无害环境：高性能、紧凑型热声制冷

• 批准号: 0729905
• 负责人: Laura Schaefer
• 金额: $ 30万
• 依托单位: University of Pittsburgh
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2011-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0729905&HistoricalAwards=false
• 关键词: Environmentally; Sound; Performance; Compact; Thermoacoustic

Environmentally Sound: High Performance, Compact Thermoacoustic RefrigerationThe focus of this proposal is research that will advance the development of an efficient thermoacoustic Stirling engine for a range of small-scale applications. The thermoacoustic effect was first discovered when glass blowers noticed that glass pipes emitted a noise during production when one end was hot and the other had cooled. It was not until Ceperley connected the thermoacoustic effect with the Stirling cycle by building a traveling wave heat engine in 1978 that modern thermoacoustics was born.The young field of thermoacoustics is divided into two parts: standing wave (where the crests of the sound waves appear to be fixed) and traveling wave (where the crests of the sound waves appear to move) engines. The latter is more complex but also more efficient. This complexity is one of the reasons why traveling wave technology has been largely overlooked, which allows for significant advances to be made both to this technology and its impact on a widespread basis.A thermoacoustic engine is commonly comprised of a looped oscillator and a resonator tube. Two heat exchangers and a regenerator are located inside the looped oscillator. The two heat exchangers serve as a heat source and sink, and the regenerator allows the working gas to gradually change temperature from the cold side temperature to the hot side temperature. Thermoacoustic engines utilize the self oscillation imposed on the system by the addition of heat to the hot side. Over the course of several work cycles, the amplitude of the oscillations is continuously increased, eventually reaching a level where the energy can be used in a subsequent device (such as a thermoacoustic refrigerator). One advantageous facet of the thermoacoustic Stirling process is its ability to be powered through external heating of the working gas, rendering it a prime application to be powered by solar heat and waste heat.We propose to achieve a smaller scale for a thermoacoustic Stirling heat engine by coiling the resonator tube and to drastically improve the engine's efficiency. A computational analysis of the engine's components will be conducted, focusing primarily the resonator tube and regenerator. A detailed understanding of the underlying physical phenomena occurring in these components is a significant contribution to the field of thermoacoustics. This analysis will result in an optimized tube geometry and will support the efficient downsizing of each component. The construction of an experimental prototype will incorporate the use of microfabrication for the heat exchangers and regenerators.One of the major advantages of thermoacoustic refrigeration over conventional refrigeration and a primary motivation for this work is that it does not utilize harmful refrigerants such as CFCs or HCFCs. It will be shown that thermoacoustic refrigeration can significantly decrease the environmental impact of refrigeration. Broad applications of the improved and downsized units could include refrigerators and air-conditioners for both buildings and vehicles. At the current size, efficient traveling wave thermoacoustic refrigerators are not feasible for implementation in these fields. This work will be used to promote thermoacoustics as an environmentally sound and well-developed technology. Also, the proposed work will support education in the fields of thermodynamics, fluid mechanics and acoustics through minority student outreach, classroom demonstrations, and undergraduate research.

环保型：高性能、紧凑型热声制冷本提案的重点是研究将推动一种适用于一系列小规模应用的高效热声斯特林发动机的开发。当玻璃吹塑者注意到玻璃管道在生产过程中一端是热的，另一端已经冷却时会发出噪音时，热声效应首次被发现。直到1978年塞珀利通过建造行波热机将热声效应与斯特林循环联系起来，现代热声学才诞生。热声学的年轻领域分为两部分：驻波发动机(声波的波峰似乎是固定的)和行波发动机(声波的波峰似乎是移动的)。后者更复杂，但效率也更高。这种复杂性是行波技术在很大程度上被忽视的原因之一，这使得行波技术及其广泛影响都能取得重大进展。热声发动机通常由环路振荡器和谐振管组成。两个热交换器和一个回热器位于环路振荡器内部。两个换热器作为热源和散热器，回热器使工作气体的温度从冷侧温度逐渐变化到热侧温度。热声发动机利用通过将热量添加到热端而施加在系统上的自振荡。在几个工作周期的过程中，振荡的幅度不断增加，最终达到可以将能量用于后续设备(如热声制冷机)的水平。热声斯特林过程的一个优点是它能够通过工作气体的外部加热来提供动力，使其成为由太阳能和废热提供动力的主要应用。我们建议通过盘绕谐振器管来实现热声斯特林热机的较小规模，并显著提高发动机的效率。将对发动机的部件进行计算分析，主要集中在谐振器管和再生器。对这些部件中发生的潜在物理现象的详细了解是对热声学领域的重大贡献。这一分析将导致优化的管道几何形状，并将支持每个组件的有效缩小尺寸。热声制冷相对于传统制冷的主要优点之一和这项工作的主要动机是它不使用有害的制冷剂，如氯氟烃或氟氯烃。结果表明，热声制冷可以显著降低制冷对环境的影响。改进和缩小尺寸的机组的广泛应用可能包括建筑物和车辆的冰箱和空调。在目前的规模下，高效的行波热声制冷机在这些领域的实施是不可行的。这项工作将被用来促进热声技术作为一项无害环境和发展良好的技术。此外，拟议的工作将通过少数民族学生外展、课堂演示和本科生研究来支持热力学、流体力学和声学领域的教育。