Thermally driven elastocaloric system
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Solution Overview
Problem
Existing thermally driven elastocaloric systems rely on electrical power or combustible fuel to generate thermal potentials in shape memory alloys, lacking a method to transfer thermal energy between SMAs to achieve these potentials.
Innovation Solution
A thermally driven elastocaloric system comprising two shape memory alloy members connected by a mechanism that transfers compressive or tensile forces between them, utilizing a working fluid to transfer heat and generate thermal potentials without external power sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical power or combustible fuel is used to generate thermal potentials in shape memory alloys, then thermal potentials can be reliably generated, but the system complexity and external power requirements increase
Solution Approach 1:
The system uses the shape memory alloy's own thermal energy storage and phase change properties to generate the thermal potentials needed for operation. The SMA members absorb and release thermal energy through their martensite-austenite phase transitions, eliminating the need for external electrical power or fuel sources to generate heating and cooling potentials.
Solution Approach 2:
A thermal energy transfer medium (such as a working fluid or direct thermal contact) serves as an intermediary to transfer thermal energy between the shape memory alloy members. This mediator enables the thermal coupling that allows one SMA member to drive the phase transition of another, replacing the need for external power conversion systems.
2Reliability
If external power sources are used to mechanically drive shape memory alloys, then thermal potentials can be generated, but energy efficiency decreases due to conversion losses
Solution Approach 1:
The system replaces mechanical drive systems (actuators, motors) with a direct thermal energy transfer mechanism. Instead of converting electrical or chemical energy to mechanical work and then to thermal potential, the system directly transfers thermal energy between SMA members, eliminating intermediate conversion steps and associated energy losses.
Solution Approach 2:
The system utilizes the phase transition properties of shape memory alloys (martensite-austenite transformations) to directly convert thermal energy between different forms. When one SMA member undergoes phase transition, it releases or absorbs thermal energy that directly drives the phase transition of the other SMA member, creating an efficient energy transfer pathway without mechanical conversion losses.
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
Enables the generation of heating and cooling potentials in SMAs solely through thermal energy transfer, eliminating reliance on electrical power or fuel, suitable for applications like HVAC systems and refrigeration.
Implementation Method 1
a first shape memory alloy (SMA) member... a second shape memory alloy (SMA) member... configured to transfer a force between the first SMA member and the second SMA member
Implementation Method 2
A shape memory alloy (SMA) is a material that can change crystallographic structure (e.g., in a reversible manner between martensite and austenite) when force is applied to the SMA or when heat in transferred to or from the SMA
Implementation Method 3
Elastocaloric cooling or heating is a solid-state based technology, which utilizes materials known as shape memory alloys
Implementation Method 4
When placed in tension, the SMA absorbs thermal energy and generates a cooling potential (e.g., as an endothermic reaction)
Implementation Method 5
when placed in compression, the SMA generates a heating potential (e.g., as an exothermic reaction)
Data Source
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AI summary
A thermally driven elastocaloric system 100 and a method for generating at least one of a heating potential 400 and a cooling potential 500 are provided. The thermally driven elastocaloric system 100 includes a first shape memory alloy (SMA) member 110, a second shape memory alloy (SMA) member 120, and a connection mechanism 130 configured between the distal end 111 of the first SMA member 110 and the distal end 122 of the second SMA member 120. The connection mechanism 130 is configured to transfer a force 300, 600 between the first SMA member 110 and the second SMA member 120. The transfer of a compressive force 300 to an SMA member 110, 120 may generate a heating potential 400 in the SMA member 110, 120, and the transfer of a tensile force 600 to an SMA member 110, 120 may generate a cooling potential 500 in the SMA member 110, 120. Whether a compressive force 300 or a tensile force 600 is transferred may be dependent on whether heat 200 is transferred to or from a SMA member 110, 120.