Asymmetrically heated multi-stage travelling-wave thermoacoustic electricity generator (original) (raw)
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Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 2018
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CONSTRUCTION AND PERFORMANCE ANALYSIS OF A TWO-STAGE TRAVELING-WAVE THERMO-ACOUSTIC GENERATOR
Proceedings of the ASME 20 20 International Mechanical Engineering Congress and Exposition IMECE2020, 2020
Thermo-acoustic technology offers the possibility to convert heat energy into a sound-wave that can potentially be used to generate electricity through a linear alternator. The construction of a two-stage traveling-wave thermo-acoustic generator is described in this paper. The potential of conversion of heat into electricity has been investigated experimentally. The effect of the geometrical configurations of the thermo-acoustic system on its performance has been analyzed. The two thermo-acoustic engine cores were tested separately and subsequently combined to build a two-stage system. Two different configurations of engine cores have been considered namely series and parallel configuration. Hence, the effect of the orientation of the engine core has been investigated to get an insight into its effect on the output of the device. Parallel arrangement was found to be the most efficient configuration. An onset time of 3.15 minutes was recorded for the device to generate a sound wave. This system has achieved 125.7 dB corresponding to an output voltage of 486 mV. This study guides the development of more efficient electricity generators using thermo-acoustic technology.
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The current development of thermo-acoustic devices suggests that there is a possibility to enhance their performance even further. This technology could potentially contribute to the effort to swap conventional pollutant energy refrigerators/generators with environmental friendlier systems in the forthcoming years. The configuration of the regenerator is so far believed to be one of the factor that could contribute to the improvement the performance of the engine. This paper aims to investigate the behaviour of a designed thermo-acoustic engine when changing the porosity of the regenerator. It also aims to provide guidance on the construction, from mostly scrap and cheap materials, of a traveling wave looped-tube thermoacoustic engine capable of generating higher sound level. The design is conducted using a code program named Design Environment for Low-Amplitude Thermo-acoustic Energy Conversion that helps to simulate in fine details the performance of the device. Three ceramic subs...
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Journal of Energy Resources Technology-transactions of The Asme, 2021
Waste heat recovery from power plants and industries requires a new type of electricity generator and related technological developments. The current research work is aimed at the design of a multi-kilowatt thermoacoustic electric generator, which can be employed as the bottoming cycle of a gas-turbine power plant or for industrial waste heat recovery. The proposed device converts thermal energy into acoustic power and subsequently uses a piezoelectric alternator to convert acoustic power into electricity. The challenge in designing such a device is that it has to be acoustically balanced. The performance of the device is greatly affected by numerous parameters such as frequency of the traveling acoustic wave, heat exchanger parameters, regenerator dimensions, acoustic feedback loop, etc. The proposed device is a lab-scale demonstration targeted to produce few kilowatts of electric power from a 20 kWth heat source. DeltaEC software is used to achieve the acoustically balanced configuration of the device. The DeltaEC model outcomes are used to arrive at the optimized design of the device and its components. The analytical method, the optimized geometrical dimensions of thermoacoustic components, and the minimum required conditions of heat source input are presented in this paper. 1
Development and performance evaluation of a single stage travelling-wave thermo-acoustic generator
2019 Open Innovations (OI), 2019
Thermo-acoustic systems are being considered as a potential solution for electricity generation. This work describes the construction of a single stage travelling-wave thermo-acoustic generator. Secondly, an experimental investigation into the effect of the heat source on the potential of the device for electricity generation is performed. The magnitude of the sound generated by the engine, the onset time and the magnitude of electricity generated by the linear alternator have been considered as performance indicators for the device developed. This paper provides clarity on the potential for thermo-acoustic system for sound-to-electricity conversion. Clear trends showing the effect of inputs parameters on device performance have been disclosed. The minimum/maximum amount of heat that has produced a sound was 339/634 o C corresponding to sound of 114.0/114.13 dB and a voltage of 278/319 mV. Although the efficiency of the sound-to-electricity conversion was low, this work proves the viability of thermo-acoustic as the alternative solution for electricity generation.
Numerical investigation of a looped-tube traveling-wave thermoacoustic generator with a bypass pipe
Energy Procedia
A new configuration ("a looped-tube with a bypass pipe") was recently proposed for low temperature travelling wave thermoacoustic engines and a prototype using atmospheric air as the working gas achieved an onset temperature difference as low as 65 °C. However, no further research has been reported about this new configuration to reveal its advantages and disadvantages. This paper aims to analyse this type of engine through a comprehensive numerical research. An engine of this type having dimensions similar to the reported prototype was firstly modelled. The calculated results were then qualitatively compared with the reported experimental data, showing a good agreement. The working principle of the engine was demonstrated and analysed. The research results show that an engine with such a bypass configuration essentially operates on the same thermodynamic principle as other travelling wave thermoacoustic engines, differing only in the design of the acoustic resonator. Both extremely short regenerators and a near-travelling wave resonator minimise the engine's acoustic losses, and thus significantly reduce its onset temperature difference. However, such short regenerators likely cause severe heat conduction losses, especially if the engine is applied to heat sources with higher temperatures. Furthermore, the acoustic power flowing back to the engine core is relatively low, while a large stream of acoustic power has to propagate within its resonator to maintain an acoustic resonance, potentially leading to low power density. The model was then applied to design an engine with a much longer regenerator and higher mean pressure to increase its power density. A thermoacoustic cooler was also added to the engine to utilise its acoustic power, allowing the evaluation of thermal efficiency. The pros and cons of the engine configuration are then discussed.
Design Optimization of a Multi-kW Thermoacoustic Electric Generator Using DeltaEC Model
2021
Waste heat recovery from power plants and industries requires a new type of electricity generators and related technological developments. The current research work is aimed at the design of a multi-kilowatt thermoacoustic electric generator, which can be employed as the bottoming cycle of a gas-turbine power plant or for industrial waste heat recovery. The proposed device converts thermal energy into acoustic power and subsequently uses a piezoelectric alternator to convert acoustic power into electricity. The challenge in designing such a device is that it has to be acoustically balanced and the performance of the device is greatly affected by numerous parameters such as frequency of the traveling acoustic wave, heat exchanger parameters, regenerator dimensions, acoustic feedback loop, etc. The proposed device is a lab-scale demonstration targeted to produce a few kilowatts of electric power from a 20 kWth heat source. To achieve the acoustically balanced configuration of the device, DeltaEC software is used. The DeltaEC model outcomes are used to arrive at the optimized design of the device and its components. The analytical method, the optimized geometrical dimensions of thermoacoustic components and the minimum required conditions of heat source input are presented in this paper.
A Sustainable Solution for Electricity Generation using Thermoacoustic Technology
2017 International Conference on the Industrial and Commercial Use of Energy (ICUE), 2017
This work explores the use of thermo-acoustic system as alternative technology for electricity generation. This technology is proposed as a potential replacement for low-cost electrical power generation because of its simplicity and lack of moving parts. Thermo-acoustic generators provides clean electrical energy to power small appliances. The energy conversion from heat into sound wave is done within thermo-acoustic engine. The latter is coupled to a linear alternator for electricity generation. The study investigates the influence of the geometrical configuration of the device on the whole functionality of the generator. The paper studies the technology through experimental trails performed using a simple arrangement to simulate the generator. The experiment is conducted in phases; the first phase identifies the best geometrical configuration of the thermo-acoustic engine by measuring the sound pressure level and the temperatures. The second phase consist of measuring the electricity generated using a Loudspeaker. The results obtained show the potential for this sustainable solution for electricity generation.