Thermoacoustic Engine for more cheap energy than the Rhombic Stirling to go off grid ?

In this video I show you the beginning of the investigation into which Stirling engine concept could become the successor to the Rhombic Stirling.

This is a repost of the video after I had to change some pictures.

The Stirling engines I have built so far are too complex for energy self-sufficiency and therefore too expensive and maintenance-intensive.

I would now like to extensively investigate which engine concept would be best for my next project to produce diy energy to support our Solar installation in times of low sunshine and go off grid completely!

Thermoacoustic engines have a simple configuration, a high reliability, low manufacturing costs and need little maintenance.
The only moving part is the electricity generator.

The Thermoacoustic engine is still a relatively new invention which has not been researched much and offers a lot of potential for improvement.

There are several different configurations like the TASHE and the TA-SLiCE which relay on the principles of traveling and standing sound waves.

Apart from the electric generator, they have no moving parts, providing reliability, low manufacturing costs and reduced maintenance.
They consist of passive acoustic ducts and cavities which contain a gas suitable to support an acoustic wave.

The core of the engine contains a hot heat exchanger, a cold heat exchanger and a regenerator between the both to impose a temperature difference on the working gas.
The working fluid undergoes a thermodynamic cycle similar to that of the Stirling.

The Thermoacoustic engine has no moving parts but unfortunately it is impossible to generate electricity of the engine without mechanical movement.
This removes the biggest advantage of the thermoacoustic engine, the absence of wear and mechanical friction.
The type of energy-generating systems used for the conversion of acoustic energy into electrical energy is therefore of great importance and has a strong influence on endurance property,performance and efficiency.

Thermoacoustic generators are scaleable from watts to kilowatts.
Simple annular configurations with air at atmosperic pressure and low cost loudspeaker transducers provide up to 25 watts of power.
More sophisticated technology with higher temperatures, helium at higher pressures and better mechanical resonators have thermoacoustic efficiencies up to 30 % and power levels of 25 - 1000 watts.
The most powerful Thermoacoustic engines use a circular arrangement with multiple cores in series each with its own power extraction unit.
They reach overall efficiencies up to 20 % and a maximum power output of 4.5 KW.

The key topic to improve the performance of the Thermoacoustic engine is the optimization of the conversion of acoustic power into electrical power as many losses are incurred here.

Thermoacoutic engines can be developed and optimized using numerical models together with computational fluid dynamics.
The design of the acoustic field is quite complex especially if you are not familiar with oscillating systems.
The general linear theoretical assumptions on which the operation of the Thermoacoustic engine is based are quite complex and not very intuitive.

The Thermoacoustic engine offers many simplifications and advantages.
On the other hand, the very specific theoretical design does not correspond to my experience.
I am very undecided but find many aspects very interesting and add the Thermoacoustic engine to the list for my next project!

What do you think about the Thermoacoustic Engine, please let me know and write it in the comments!

Thank you very much for your attention.

Thank you so much for the artwork from my wonderful daughters Anna and Greta!

Sources:

[1] Yu Z, Jaworski AJ, Backhaus S. Design of a low-cost thermoacoustic electric generator and its experimental verification 10th ASME

[2] Kang H, Cheng P, Yu Z, Zheng H A two-stage traveling-wave thermoacoustic electric generator with loudspeakers as alternators Appl Energy 2015

[3] Sun DM, Wang K, Zhang XJ, Guo YN, Xu Y, Qui LM A traveling-wave thermoacoustic electric generator with a variable electric R-C load Appl Energy 2013

[4] Sun DM, Wang K, Zhang XJ, Xu Y, Zou J, Wu K Operating characteristics and performance improvements of a 500W traveling-wave thermoacoustic electric generator Appl Energy 2015

[5] Wu Z, Yu G, Zhang L, Dai W, Luo E Development of a 3kW double-acting thermoacoustic Stirling electric generator Appl Energy 2014

[6] Bi T, Wu Z, Zhang L, Yu G, Luo E, Dai W Development of a 5kW traveling-wave thermoacoustic electric generator Appl Energy 2015

[7] R.S. Reid, W.C. Ward, G.W. Swift Cyclic thermodynamics with open flow Phys. Rev. Lett. 80 1998

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