Journal ArticleDOI
Design optimization of thermoacoustic refrigerators
Martin Wetzel,Cila Herman +1 more
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TLDR
The simplified linear model of thermoacoustics - the short stack boundary layer approximation - is implemented into a systematic design and optimization algorithm and serves as an easy-to-follow guideline for the design of therMOacoustic refrigerators.Abstract:
Thermoacoustic refrigeration was developed during the past two decades as anew, environmentally safe refrigeration technology. The operation of thermoacoustic refrigerators employs acoustic power to pump heat. Nowadays, as commercial applications are sought, it is important to be able to obtain fast and simple engineering estimates for the design and optimization of prototypes. This paper provides such estimates by implementing the simplified linear model of thermoacoustics - the short stack boundary layer approximation - into a systematic design and optimization algorithm. The proposed algorithm serves as an easy-to-follow guideline for the design of thermoacoustic refrigerators. Performance calculations applying the algorithm developed in this paper, predict values of 40–50% of Carnot's efficiency for the thermoacoustic core, the heart of a thermoacoustic refrigerator. One reason that these efficiencies have not yet been achieved in devices built to date, is the poor performance of the heat exchangers in thermoacoustic refrigerators. This issue and other remaining challenges for future research are also addressed in the paper. Solving these problems in the near future, we believe, will bring an environmentally safe refrigeration technology a step closer to commercial use.read more
Citations
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Journal ArticleDOI
Design and optimization of thermoacoustic devices
Hadi Babaei,Kamran Siddiqui +1 more
TL;DR: In this article, a comprehensive design and optimization algorithm is developed for designing thermoacoustic devices that can serve as sustainable refrigeration systems, and new features based on the energy balance are also included to design individual thermo-acoustic engines and acoustically-driven thermoACoustic refrigerators.
Journal ArticleDOI
Performance analysis of the standing wave thermoacoustic refrigerator: A review
TL;DR: In this article, the authors reviewed past studies to achieve the desired outputs; lowest temperature, the highest temperature difference generated across the stack, the lowest acoustical work required for cooling, or/and the highest coefficient of performance (COP) of the standing wave thermoacoustic refrigerator and various attempts at optimization in terms of the many parameters that represent the outcomes.
Journal ArticleDOI
Status of not-in-kind refrigeration technologies for household space conditioning, water heating and food refrigeration
TL;DR: In this paper, the authors present a review of the next generation not-in-kind technologies to replace conventional vapor compression refrigeration technology for household applications, which are sought to provide energy savings or other environmental benefits for space conditioning, water heating and refrigeration for domestic use.
Journal ArticleDOI
Measurement of acoustic velocity in the stack of a thermoacoustic refrigerator using particle image velocimetry
TL;DR: In this article, a specific particle image velocimetry measurement is performed inside a thermoacoustic refrigerator, where the velocity is measured inside the oscillating boundary layers, between the plates of the stack, and compared to a linear model.
Journal ArticleDOI
Experimental study on the heat transfer at the heat exchanger of the thermoacoustic refrigerating system
TL;DR: In this article, the authors studied the relationship between the heat transfer coefficient at the heat exchangers, the mean pressure and frequency of oscillation, and showed that higher mean pressures result in higher heat transfer coefficients if the thermoacoustic refrigerating system operates at the corresponding resonant frequency.
References
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Proceedings Article
Thermoacoustic engines
W. P. Arnott,R. Raspet,H.E. Bass +2 more
TL;DR: In this paper, an approximate analysis of energy flow and acoustical measurements of a thermoacoustic prime mover with arbitrary cross-sectional geometry is given. But this analysis is restricted to the case of TAEs with circular or parallel slit pore geometry.
Journal ArticleDOI
Transition to turbulence in oscillating pipe flow
P. Merkli,H. Thomann +1 more
TL;DR: In this paper, the authors used hot wires and flow visualization by means of smoke, and provided new details on turbulence in a Stokes layer, showing that turbulence occurs in the form of periodic bursts which are followed by relaminarimtion in the same cycle and do not lead to turbulent flow during the whole cycle.
Journal ArticleDOI
Analysis and performance of a large thermoacoustic engine
TL;DR: In this paper, measurements and analysis of a 13 cm−diam thermo-acoustic engine are presented, and the authors identify several causes of this amplitude-dependent deviation, including resonanceenhanced harmonic content in the acoustic wave, and a new, first-order temperature defect in thermoacoustic heat exchangers.
Journal ArticleDOI
Design environment for low-amplitude thermoacoustic engines
W. C. Ward,G. W. Swift +1 more