System and method for supporting SMA material and optimising heat transfer in a SMA heat pump
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Solution Overview
Problem
Current heat pump technologies are thermally inefficient, prone to SMA material buckling, and have poor Coefficient of Performance (CoP) values, which limits their effectiveness and lifespan, especially at low temperatures and high operating conditions.
Innovation Solution
A heat pump system utilizing a Shape-Memory Alloy (SMA), Negative Thermal Expansion (NTE), or elastocaloric material core with a support system to prevent buckling and enhance heat transfer, featuring a series of buckling supports and turbulence generators to optimize fluid flow and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the diameter of the SMA rod is increased to increase buckling length, then the buckling resistance is improved, but the surface area to volume ratio increases resulting in reduced heat transfer rate
Solution Approach 1:
The SMA rod is segmented into multiple sections with support systems positioned at intervals along its length. This segmentation allows the rod to maintain higher buckling resistance through structural support while preserving the high surface area to volume ratio of thinner sections, thus maintaining efficient heat transfer rates.
Solution Approach 2:
A support system acts as an intermediary between the SMA rod and the housing. This intermediary provides mechanical support to prevent buckling without requiring an increase in rod diameter, thereby maintaining the rod's high surface area to volume ratio and efficient heat transfer characteristics.
2Device complexity
If conventional heat pump technologies are used, then the system structure is simple, but the Coefficient of Performance (CoP) is limited and thermal efficiency is poor
Solution Approach 1:
The system changes the fundamental operating parameters by using SMA material phase transition temperatures and mechanical properties instead of conventional refrigerant pressure-temperature relationships. This allows operation at higher CoP values while maintaining a relatively simple system structure through the use of solid-state phase change materials.
Solution Approach 2:
The patent employs composite construction combining SMA material with support systems and housing structures that optimize both mechanical stability and thermal transfer. This composite approach improves thermal efficiency while keeping the overall system structure manageable through integrated design.
3Device complexity
If SMA material is used without support system, then the device complexity is reduced, but the SMA material is prone to buckling leading to system failure
Solution Approach 1:
The support system is pre-installed within the housing before the SMA rod is installed. This preliminary action ensures that the support structure is in place to prevent buckling from the outset, extending system lifespan without requiring complex post-installation adjustments or monitoring systems.
Solution Approach 2:
The support system uses simple, inexpensive structural elements that can be easily manufactured and installed. These support components are designed to be replaceable if needed, providing reliable buckling prevention through simple geometry rather than complex, expensive mechanisms.
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
The solution increases the lifespan of the heat pump system, enhances heat transfer rates, and improves the Coefficient of Performance (CoP), allowing for more efficient energy transfer and reduced manufacturing costs while maintaining high power output.
Implementation Method 1
a Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric material core positioned in a housing and adapted to absorb heat and store thermal energy
Implementation Method 2
a Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric material core
Implementation Method 3
a Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric material core
Implementation Method 4
a support system is configured to engage with the SMA material to prevent the SMA material buckling when a stress is applied
Implementation Method 5
turbulence generators to optimize fluid flow and heat transfer
Implementation Method 6
enhances heat transfer rates, and improves the Coefficient of Performance (CoP), allowing for more efficient energy transfer
Data Source
AI summary
The invention provides heat pump system a Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric material core positioned in a housing and adapted to absorb thermal heat and store energy in response to a first fluid inputted at a first temperature. The housing is configured to receive the fluid at the first temperature via an inlet to cause the SMA or NTE or elastocaloric material core to change state. A device is configured to apply stress on the SMA or NTE or elastocaloric core in the housing to cause the SMA or NTE or elastocaloric core to change state. A support system is configured to engage with the material in the core to prevent the material buckling when the stress is applied wherein the support system comprises a series of buckling supports positioned along at least one length of the SMA or NTE or elastocaloric material core. The support system provides a mechanical buckling support and heat transfer optimisation for fluid flow in a SMA heat pump during compression.