Thermoacoustic Machine Electric Feedback for Compact Energy Conversion
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Solution Overview
Problem
Existing thermoacoustic machines face challenges in achieving high non-dimensional impedance with small elements, such as pistons and membranes, while minimizing mass movement and mechanical complexity, which limits their compactness and efficiency.
Innovation Solution
A thermoacoustic machine design featuring a porous matrix between heat exchangers with an electrical feedback circuit to convert acoustic energy into electrical energy, eliminating the need for membranes or jet pumps and simplifying manufacturing by using linear architectures with small dimensions and reduced viscous losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If membranes or jet pumps are used to prevent mass movement in loop machines, then reliability is improved, but device complexity increases and manufacturing becomes more difficult
Solution Approach 1:
The patent extracts and eliminates the membrane component from the system by transitioning to a linear architecture where mass movement is inherently prevented by the system configuration rather than requiring additional preventive components
Solution Approach 2:
The patent replaces the mechanical membrane-based mass movement prevention system with an electrical feedback control system that uses electrical signals to control acoustic energy conversion, eliminating complex mechanical components
2Volume of moving object
If high non-dimensional impedance is achieved with small elements, then compactness is improved, but viscous losses increase and efficiency decreases
Solution Approach 1:
The patent introduces an electrical feedback loop that monitors and controls the acoustic energy conversion process, allowing optimization of operating parameters to minimize viscous losses while maintaining high impedance conditions with compact elements
Solution Approach 2:
The patent changes the operational parameters through electrical control, adjusting acoustic energy conversion in real-time to maintain optimal performance with small elements, reducing viscous losses through precise parameter management rather than relying on larger dimensions
3Device complexity
If linear architecture is used instead of loop architecture, then device complexity is reduced and manufacturing is simplified, but ability to control mass movement becomes challenging
Solution Approach 1:
The patent replaces mechanical mass movement control mechanisms with an electrical feedback control system that uses electrical signals to regulate acoustic energy conversion, maintaining reliability while simplifying the mechanical architecture
Solution Approach 2:
The linear architecture with electrical feedback enables the system to self-regulate acoustic energy conversion and inherently prevent mass movement through its configuration, eliminating the need for additional control components
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design enables efficient energy conversion with reduced space requirements, lower operating acoustic flow rates, and lower pressure losses, achieving high yields and compactness without the need for complex mechanical systems.
Implementation Method 1
thermoacoustic machine, that is to say thermal machines such as wave generators... using within a fluid, contained in a closed enclosure... thermodynamic cycles of the Stirling or Ericsson type allowing thermoacoustic energy conversion
Implementation Method 2
In a thermoacoustic machine the sound wave imposes an oscillation on the working fluid around an average position... the oscillation around the average position is simultaneously accompanied by phases of compression/expansion of the fluid
Implementation Method 3
The implementation of reversible thermodynamic cycles of the Stirling or Ericsson type requires very intimate contact between the fluid and the solid during its movement between the two heat sources located within the solid matrix... This solid matrix is more or less dense and allows good propagation of acoustic waves since the dimensions of the pores or parallel channels which compose it are much lower than the wavelength of the acoustic field considered
Implementation Method 4
This thermoacoustic cell is composed of a solid and porous matrix interposed between a first so-called 'hot' heat exchanger at temperature Tc and a second so-called 'cold' heat exchanger at temperature Tf
Implementation Method 5
at least one first energy conversion system arranged in the immediate vicinity of the output of the at least one cell relative to the direction of propagation of the acoustic energy and intended to transform the acoustic energy at the output of the at least one cell into energy electrical
Data Source
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AI summary
The present invention relates to a thermoacoustic machine which includes: at least one thermoacoustic cell (1) located in a dimensionless high-impedance area made up of a porous matrix (4) inserted between a first heat exchanger (2) operating at a first temperature T1 and a second heat exchanger (3) operating at a second temperature T2 that is different from the first temperature T1, and which enables a Stirling or Ericsson thermodynamic cycle to be carried out by carrying out a motor or heat pump cycle, at least one first energy-conversion system (10) arranged immediately next to the output of the thermoacoustic cell (1) relative to the direction of propagation of the acoustic energy and intended for transforming the acoustic energy produced at the output of the thermoacoustic cell (1) into electric power and, optionally, an additional means (50) used for starting the machine. According to the invention, the machine preferably also includes at least one second energy-conversion system (20) having an output (21) connected to the input of said thermoacoustic cell (1) relative to the direction of propagation of the acoustic energy, and an input (25); and an electric feedback circuit (30) intended for transferring all or part of the electric power produced at the output of the first conversion system (10) towards the input (25) of the second conversion system (20), the respective geometry and/or mechanical characteristics of said conversion systems (10, 20) and the thermoacoustic cell (1) being such that the phase difference between the acoustic pressure and the acoustic vibration of the fluid creates a progressive sound field inside the thermoacoustic cell.