Innovative Solar-Energy-Driven Power Converter Efficient Operation of Thermoacoustic Engines (original) (raw)

Review on the conversion of thermoacoustic power into electricity

The Journal of the Acoustical Society of America, 2018

Thermoacoustic engines convert heat energy into high amplitude acoustic waves and subsequently into electric power. This article provides a review of the four main methods to convert the (thermo)acoustic power into electricity. First, loudspeakers and linear alternators are discussed in a section on electromagnetic devices. This is followed by sections on piezoelectric transducers, magnetohydrodynamic generators, and bidirectional turbines. Each segment provides a literature review of the given technology for the field of thermoacoustics, focusing on possible configurations, operating characteristics, output performance, and analytical and numerical methods to study the devices. This information is used as an input to discuss the performance and feasibility of each method, and to identify challenges that should be overcome for a more successful implementation in thermoacoustic engines. The work is concluded by a comparison of the four technologies, concentrating on the possible area...

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.

Computational study on thermoacoustic heat engine for proposing a new method renewable technique

APPLIED PHYSICS OF CONDENSED MATTER (APCOM 2019), 2019

Thermoacoustic Heat Engine is a renewable technology in the energy conversion field. This system is a suitable technology for catching the waste heat where it provides about 400 °C to 600 °C to fulfil the valuable work. The aim of this study is to determine the appropriate parameters in thermoacoustic heat engine for standing wave and analyse the highest performance of acoustic power. Delta EC software is used to do the code for simulating the thermoacoustic heat engine where it focus on four parameters which are frequency, pressure, temperature and heat exchanger length in order to know the better value used for design a thermoacoustic system. As result, the acoustic power with 2 mm of Hot Heat Exchanger (HHX) and 20 mm of Cold Heat Exchanger(CHX) length which gets from the graph of simulation in Delta EC is higher than research before which is 9.4 W. Thus, it is proving that Delta EC software is possible in order to get the optimum value in design thermoacoustic heat engine for standing wave.

A solar-powered traveling-wave thermoacoustic electricity generator

Solar Energy, 2012

Traveling-wave thermoacoustic electricity generator is a new external-combustion type device capable of converting heat such as solar energy into electric power. In this paper, a 1 kW solar-powered traveling-wave thermoacoustic electricity generation system is designed and fabricated. The system consists of a traveling-wave thermoacoustic electricity generator, a solar dish collector and a heat receiver. In the preliminary tests, using electric cartridge heaters to simulate the solar energy, a maximum electric power of 481 W and a maximum thermal-to-electric efficiency of 15.0% were achieved with 3.5 MPa pressurized helium and 74 Hz working frequency. Then, after integrating the traveling-wave thermoacoustic electricity generator with the solar dish collector and the heat receiver, the solar-powered experiments were performed. In the experiments, a maximum electric power of about 200 W was obtained. However, due to the solar dish collector problems, the heating temperature of the receiver was much lower than expected. Optimizations of the collector and the heat receiver are under way.

Design Considerations for Thermoacoustic Engines for Low Onset Temperature and Efficient Operation

Thermoacoustic heat engines (TAHE) convert heat into mechanical work in the form of an acoustic wave. TAHE are further advantageous if they exploit waste heat and/or solar energy. For the acoustic wave to be generated, the heat must be added to TAHE at a temperature higher than a certain value, known as the onset temperature. In order to expand the use of thermoacoustic engines to more sources of waste heat and/or renewable energy, an optimization process is required to minimize the onset temperature while not severely compromising the first and second law efficiencies. Such optimization needs to address the effects of several TAHE's parameters on the onset temperature and efficiencies.

Design and Fabrication of Two Stage Thermoacoustic Engine to Reduce the Onset Temperature

About 60% of primary energy is treated as waste heat but the temperature of this heat is low (200-300 0 C). Thermoacoustic engine convert heat energy into high amplitude sound waves, which is used to drive thermoacoustic refrigerator or pulse tube cryocoolers by replacing the mechanical piston such as compressors. The potential of thermoacoustic engine is high but because of heat loss the actual efficiency is not so high. The onset temperature difference, defined as the minimum temperature difference across the sides of the stack at which the dynamic pressure is generated. Lowering the critical onset temperature is a challenging task. The authors designed a multistage thermoacoustic engine which oscillates with relatively low critical onset temperature TH/TR. The influence of the position of honeycomb ceramics is also investigated in this study. Introduction There are energy crises around the world so there has been a demand to use more efficient energy. And making use of waste heat is one way to reduce the energy crises. Currently a heat of 100 0 C or less which is wasted each year in Japan is about 22.3 Peta Calorie ≒ 9.34×10 16 J. This amount is greater than the amount of geothermal energy produced in the year 2010 which was 2.3×1016 J [1]. It is possible to use this heat effectively which can be very important in the future. Devices in which heat-sound interactions play an important role are known as thermoacoustic systems [2]. Generally, as described by Swift [3] and Ceperley [4], etc., thermoacoustic engines are classified into the standing wave engine and travelling wave engine by leading phase φ. In the standing wave engine, gas parcels with φ = 90 0 convert heat to acoustic energy through irreversible thermal contacts between the working gas and the walls of the regenerator. Such engines have been constructed for coolers [5]. Standing wave type with the advantage to oscillate at smaller TH/TR, while travelling wave type has higher energy conversion efficiency [5]. Amplification ratio of the acoustic work as shown in the figure 1, can be expressed as

A thermoacoustic-Stirling heat engine: Detailed study

Journal of The Acoustical Society of America, 2000

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.

Proceedings of the 3rd International Workshop on Thermoacoustics

2015

Thermoacoustic refrigeration systems: recent developments TS02 Paweł Owczarek Details and experimental results of a stand-alone container cooled by a solar driven multi-stage traveling wave thermoacoustic system TS04 Chris Lawn Optimization of the loop in a travelling-wave thermo-acoustic engine TS05 Maurice-Xavier Francois The VALTA project: full scale conversion of CHP engine flue gas heat into electricity 12:20 13:20 Lunch Grand café 13:20 14:40 Session 2a Erlenmeyer AE05 Douglas Wilcox Development of a compact thermoacoustic-Stirling electric generator AE02 Jeffrey Lin High-fidelity simulations of a standing-wave thermoacousticpiezoelectric engine AE04 Bakhtier Farouk Signal conditioning of carbon nanotube loudspeaker AE01 Ken Kaneuchi Evaluation of bi-directional turbines using the two-sensor method 14:40 14:50 Coffee The Gallery 14:50 16:10 Session 3a Erlenmeyer AE03 Johan Brussen Modeling and controlling the generator of a thermoacoustic Stirling engine AE06 Maurice-Xavier Francois Space thermoacoustic radio-isotopic power system: SpaceTRIPS TS15 Hiroaki Hyodo Dynamics of forced synchronization in thermoacoustic system 16:10 16:20 Coffee The Gallery 16:20 17:20 Session 4a Erlenmeyer TC01 Marialuisa Napolitano The role of stack non acoustic parameters on thermodynamic performance of standing wave devices TC02 Esmatullah Maiwand Sharify CFD study of oscillatory flow around parallel plates in a traveling-wave thermoacoustic engine

DESIGN OF A STANDING-WAVE THERMOACOUSTIC ENGINE

The project entitled 'Stove for Cooking, Refrigeration and Electricity' has the ambitious objective of making a 150 W electricity generator based on thermoacoustic principles that is driven by the heat of a wood-burning stove. With a linear alternator involving the only moving part, it is intended that the device should eventually be produced at very low cost for widespread deployment in under-developed countries. The first concept to be explored on the grounds of simplicity was the so-called 'standing-wave' design in which only a small fraction of the acoustic pressure is in-phase with the acoustic velocity. The engine consisted of a closed linear duct containing a high-temperature heat exchanger connected to the heat source and a low-temperature heat exchanger rejecting heat to the surroundings, with a 'stack' of narrow channels between them, and a linear alternator at the low-temperature end of the duct. The high-temperature heat exchanger concept was one of radiative transfer from a ceramic bulb in the fire to a number of metal plates spanning the duct, and thence into the self-excited acoustic waves. The conservation equations of thermoacoustics were solved together with equations describing the radiative heat exchange, in order to determine the overall performance of this concept in terms of the acoustic power that would be incident on a matched alternator at the chosen frequency. Sensitivity studies were undertaken to examine the influence of the mean pressure and of the composition of gas in the duct, and of the length and diameter of the passages in the stack. Ultimately it was decided that the alternator could not be matched to the high acoustic pressures involved (>100 mbar) and attention was switched to a 'travelling-wave' device.