A Traveling Wave Thermoacoustic Refrigerator within Room Temperature Range
01 Jan 2005-pp 189-194
TL;DR: A traveling wave thermoacoustic refrigerator that works in the civil refrigeration range, since traveling wave refrigerators have higher efficiencies than standing-wave refrigerators, is presented in this paper.
Abstract: Thermoacoustic refrigerators use sound waves to generate cooling. Furthermore, they use inert gases that are friendly to the environment. Their unique working mechanism and promising future have attracted many researchers. This article focuses on the design of a traveling wave thermoacoustic refrigerator that works in the civil refrigeration range, since traveling wave refrigerators have higher efficiencies than standing wave refrigerators. According to linear thermoacoustic theory, two analytical methods, the lumped-element network and transfer matrixes, are discussed for analysis of the thermoacoustic systems. Several possible modes for achieving efficient thermoacoustic refrigeration are analyzed with the simplified lumped-element network method. Then, a feasible thermoacoustic refrigeration mode is chosen and optimized with the transfer matrix method. The goal is to achieve a relatively high cooling capacity at a temperature of 250 K. The calculation results show that, with helium, the refrigerator can have a cooling power of 80 W and achieve a COP of 2.86; this corresponds to a relative Carnot efficiency of 57%. According to this, we have constructed a refrigerator. It has achieved a no-load cooling temperature of 263 K when driven by a mechanical compressor with helium, and achieved a cooling power of 80 W at 274 K when driven by a standing wave thermoacoustic engine with nitrogen at the pressure ratio of 1.09.
Citations
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TL;DR: In this paper, the authors identify and describe five alternative cooling technologies (magnetic, thermionic, thermoacoustic, thermoelectric, and thermotunnel) and qualitatively assesses the prospects of each technology relative to vapor compression for space cooling and food refrigeration applications.
Abstract: This article identifies and describes five alternative cooling technologies (magnetic, thermionic, thermoacoustic, thermoelectric, and thermotunnel) and qualitatively assesses the prospects of each technology relative to vapor compression for space cooling and food refrigeration applications. Assessment of the alternatives was based on the theoretical maximum percent of Carnot efficiency, the current state of development, the best percent of Carnot efficiency currently achieved, developmental barriers, and the extent of development activity. The prospect for each alternative was assigned an overall qualitative rating based on the subjective, composite view of the five characteristics.
81 citations
TL;DR: In this article, a gas-liquid-coupled heat-driven thermo-acoustic refrigerator with different working gases, i.e., hydrogen, helium, nitrogen and argon, was investigated under onset and steady operations.
14 citations
TL;DR: In this paper, a co-axial travelling-wave thermoacoustic cooler (TWTC) powered by a standing-wave engine (SWTE) was designed and optimized for storage of medical supplies in rural communities of developing countries with no access to electricity grid, where waste heat from cooking can be used as energy input.
12 citations
TL;DR: In this paper , a time-domain acoustic-electrical analogy (TDAEA) method is proposed and improved, then applied to explore the performance of a high-efficiency 2-stage looped direct-coupling heat-driven thermoacoustic refrigerator.
3 citations
25 May 2022
TL;DR: In this paper , an experimental investigation conducted on a loudspeaker-driven Thermo-Acoustic Refrigerator (LDTWTAR), a standing wave thermo-acoustic engine (SWTAE), a TWTAR, and a Therm-Acoustically Driven Travelling Wave ThermoAcoustic refrigerators (TADTWTARS) was conducted to get an insight into the coupling of a SWTAE and a TWTAE.
Abstract: This paper describes the experimental investigation conducted on a Loudspeaker-Driven Thermo-Acoustic Refrigerator (LDTWTAR), a Standing Wave Thermo-Acoustic Engine (SWTAE) and a Thermo-Acoustically Driven Travelling Wave Thermo-Acoustic Refrigerator (TADTWTAR). This work aims at getting an insight into the coupling of a standing wave thermo-acoustic engine and a travelling wave thermo-acoustic refrigerator and to investigate its potential for cooling. Experiments were conducted in three stages. First, an analysis of LDTWTAR to analyze the effect of the geometric configuration on the temperature difference across the regenerator and to get an insight into the effect of the parameters of the system on its performance. Secondly, analysis of a SWTAE to investigate the relationship between the frequency of the engine and the length of the resonator. Lastly, both the SWTAE and the TWTAR were coupled together to form a TADTWTAR system. An experiment on the coupled system was conducted to get an insight into the coupling of a SWTAE and a TWTAR and analyse how the parameters of the SWTAE affect the cooling performance. The investigation of the SWTAE has shown that longer resonator lengths and lower power inputs yield lower frequencies, longer onset time and higher onset temperature of the engine. The investigation of the LDTWTAR has shown that different configurations of the refrigerator loop give different results indicating that the geometric configuration of the thermo-acoustic system affects its performance. Lastly, the investigation of the TDTWTAR showed a potential of the coupling even though the results reported were significantly hindered by the limitations inherent of the SWTAE considered, particularly the heat source.
References
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TL;DR: The Atomic Processes in Plasmas Conference as mentioned in this paper is a bi-annual international conference on topics covering high-energy density plasmas, magnetically confined fusion, astrophysical plasms, fundamental atomic data and advanced modeling and plasma diagnostics, where international researchers share cutting-edge results in plasma creation, plasma experiments and plasma modeling.
Abstract: The Atomic Processes in Plasmas Conference is a bi-annual international conference on topics covering high-energy-density plasmas, magnetically confined fusion plasmas, astrophysical plasmas, fundamental atomic data and advanced modeling and plasma diagnostics. The conference lets international researchers share cutting-edge results in plasma creation, plasma experiments and plasma modeling.
770 citations
TL;DR: A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described and data are presented which show the nearly complete elimination of the streaming convective heat loads.
Abstract: A new type of thermoacoustic engine based on traveling waves and ideally reversible heat transfer is described. Measurements and analysis of its performance are presented. This new engine outperforms previous thermoacoustic engines, which are based on standing waves and intrinsically irreversible heat transfer, by more than 50%. At its most efficient operating point, it delivers 710 W of acoustic power to its resonator with a thermal efficiency of 0.30, corresponding to 41% of the Carnot efficiency. At its most powerful operating point, it delivers 890 W to its resonator with a thermal efficiency of 0.22. The efficiency of this engine can be degraded by two types of acoustic streaming. These are suppressed by appropriate tapering of crucial surfaces in the engine and by using additional nonlinearity to induce an opposing time-averaged pressure difference. Data are presented which show the nearly complete elimination of the streaming convective heat loads. Analysis of these and other irreversibilities show which components of the engine require further research to achieve higher efficiency. Additionally, these data show that the dynamics and acoustic power flows are well understood, but the details of the streaming suppression and associated heat convection are only qualitatively understood.
494 citations
TL;DR: The design strategy described in this paper is a guide for the design and development of thermoacoustic coolers and the optimization of the different parts of the refrigerator will be discussed.
165 citations
TL;DR: In this article, a self-made standing-wave thermoacoustic prime mover is used to drive a coaxial single-stage pulse tube refrigerator, which achieves a lowest refrigeration temperature of 138 K.
25 citations
01 Jan 2005
TL;DR: In this article, the authors proposed to use spring-mass resonators to reduce the size of the standing wave and traveling wave systems and achieved a no-load temperature of 105.4 K. The design and manufacture of two types of spring mass resonators has been completed and tests will be done soon.
Abstract: Thermoacoustic systems have attracted lots of attention in recent years due to their structural simplicity, high reliability, and potential for very high efficiency. There has been extensive research on standing wave and traveling wave systems, including both compressors and refrigerators. This article introduces our efforts towards building a high-efficiency and compact-sized thermoacousti-cally driven pulse tube cooler for temperatures below 80 K. Firstly, we have improved the heat exchangers in the thermoacoustic systems. By using Electrical Discharge Machining (EDM) cut heat exchangers, pressure ratios of 1.15/Helium and 1.22/Nitrogen have been obtained on a 1/4 wavelength standing wave system. Coupling the thermoacoustic compressor with a miniature pulse tube cooler has led to a lowest no-load temperature of 105.4 K. To reduce the size of the systems, we plan to use spring-mass resonators. The design and manufacture of two types of spring-mass resonators has just been completed, and tests will be done soon.
5 citations