Thermo-acoustic Engine with Electronic Wave Control

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Solution Overview

Problem

Existing heat-to-electricity conversion devices face inefficiencies due to either low efficiency without moving parts or complexity with moving parts, and combining thermo-acoustics with piezoelectrics results in significant losses from convective steady flows in toroidal feedback designs.

Innovation Solution

A thermo-acoustic engine is redesigned with a straight co-linear arrangement, utilizing electronic components for acoustical resonance instead of mechanical inertance and compliance tubes, featuring an elongated tubular body with multiple regenerators and heat exchangers, and transducers to amplify and superimpose acoustic waves for efficient energy conversion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If conventional heat-to-electricity conversion devices are used, then no moving parts are required, but efficiency is low

Engineering Contradiction:

Improveconversion efficiencyVSAvoiddevice structure

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The patent replaces mechanical resonance structures (toroidal chambers, inertance tubes, compliance tubes) with an electronic control system that generates and modulates acoustic waves. The electronic controller generates electrical signals that drive piezoelectric transducers to create acoustic waves at desired frequencies and phases, eliminating the need for complex mechanical resonance tuning while achieving high conversion efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the operating parameters by using variable frequency acoustic waves instead of fixed resonant frequencies. The electronic controller can dynamically adjust the frequency and phase of acoustic waves to optimize heat-to-electricity conversion efficiency under different operating conditions, overcoming the limitation of fixed mechanical resonance systems.

Inventive Principle:

Principle #35Parameter changes

2Loss of energy

If devices with moving parts are used, then efficiency is higher, but design and manufacturing complexity increases

Engineering Contradiction:

Improveconversion efficiencyVSAvoidmanufacturing complexity

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The patent substitutes mechanical moving parts with stationary components controlled by electronic signals. The piezoelectric transducers remain stationary while the electronic controller dynamically adjusts acoustic wave parameters, eliminating mechanical wear and simplifying manufacturing while maintaining high efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses multiple piezoelectric transducers that can be identically manufactured and then electronically coordinated to work together. This allows for standardized, repeatable manufacturing of transducer units that can be assembled in various configurations without requiring custom mechanical coupling mechanisms.

Inventive Principle:

Principle #26Copying

3Power

If toroidal feedback designs are used, then resonant high amplitude traveling acoustic waves are achieved, but significant losses occur due to convective steady flows

Engineering Contradiction:

Improveacoustic wave amplitudeVSAvoidconvective flow losses

Core Design Contradiction:

PowerVSLoss of energy

Solution Approach 1:

The patent replaces the toroidal mechanical feedback structure with electronic feedback control. Acoustic waves are generated by piezoelectric transducers driven by electronic signals, and the electronic controller adjusts wave parameters to achieve high amplitude traveling waves without creating the convective steady flows that cause losses in toroidal designs.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses periodic acoustic waves generated by piezoelectric transducers to drive heat-to-electricity conversion. The electronic controller generates sinusoidal or pulsed signals that create periodic compression and expansion cycles in the working fluid, achieving high power output without the continuous convective flows inherent in toroidal systems.

Inventive Principle:

Principle #19Periodic action

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 achieves high efficiency with no moving parts, reduces manufacturing complexity and costs, and allows for wide manufacturing tolerances, enabling compact, reliable, and versatile heat-to-electricity conversion and refrigeration applications.

Implementation Method 1

Others have attempted to combine thermo-acoustics with piezoelectrics to create a high efficiency device

Methodology Applied

Scientific EffectThermoacoustic effect: Thermoacoustic Effect

Implementation Method 2

Others have attempted to combine thermo-acoustics with piezoelectrics to create a high efficiency device

Methodology Applied

Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentUS10309376B1Alpha-stream convertor

Publication Date: 2019.06.04 UNITED STATES GOVERNMENT ADMINISTRATOR OF NASA

AI summary

A thermo-acoustic engine and/or cooler is provided and includes an elongated tubular body, multiple regenerators disposed within the body, multiple heat exchangers disposed within the body, where at least one heat exchanger is disposed adjacent to each of the multiple regenerators, multiple transducers axially disposed at each end of the body, and an acoustic wave source generating acoustic waves. At least one of the acoustic waves is amplified by one of the regenerators and at least another acoustic wave is amplified by a second one of regenerators.