Cascade SMA Heat Pump Design for Maximized Temperature Delta
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Solution Overview
Problem
Current heat pump technologies have limitations in performance, particularly in cold temperatures and are thermally inefficient, with a Coefficient of Performance (CoP) that is not effectively enhanced, leading to suboptimal energy efficiency and environmental impact due to high global warming potential refrigerants and noise issues.
Innovation Solution
A heat pump system utilizing a cascade arrangement of Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) cores that absorb and store energy, allowing for a net cooling or heating effect through phase changes and stress application, increasing the temperature delta (deltaT) and overall system efficiency by operating more like a reverse Stirling cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional heat pump technologies are used, then heating and cooling can be provided, but the Coefficient of Performance (CoP) is limited to 3-4 and energy efficiency is suboptimal
Solution Approach 1:
The heat pump system is divided into multiple independent SMA/NTE cores operating in parallel, each contributing to the overall heat transfer. This segmentation allows the system to achieve higher total thermal output and improved CoP by distributing the thermal workload across multiple phase-changing material units.
Solution Approach 2:
The system utilizes phase transitions of Shape Memory Alloys and Negative Thermal Expansion materials as the primary heat transfer mechanism. These materials absorb and release latent heat during phase changes, enabling higher thermal efficiency and improved CoP compared to conventional compression-based heat pumps.
2Volume of stationary object
If SMA material tubes with filler rods are used to remove dead thermal mass, then volume is occupied, but thermal efficiency is poor and expansion/contraction is non-uniform
Solution Approach 1:
The invention removes the ineffective filler rod configuration from the heat pump system. Instead of using SMA tubes filled with other materials, the system employs pure SMA or NTE cores that undergo uniform phase transitions, eliminating the thermal inefficiencies and non-uniform expansion/contraction problems associated with composite filler structures.
Solution Approach 2:
The system uses homogeneous SMA or NTE material cores without internal filler structures. This homogeneity ensures uniform thermal properties and consistent phase transition behavior throughout the core, improving thermal efficiency and eliminating the problems of non-uniform expansion and contraction.
3Loss of energy
If refrigerants with high global warming potential are used, then heat transfer efficiency is achieved, but environmental impact increases
Solution Approach 1:
The invention replaces conventional refrigerant-based heat transfer with a solid-state phase transition mechanism using SMA and NTE materials. This substitution eliminates the need for harmful refrigerants while maintaining efficient heat transfer through the latent heat absorption and release during material phase changes.
Solution Approach 2:
The system uses phase transitions of solid SMA and NTE materials as the heat transfer medium, replacing gaseous refrigerants. This approach achieves effective heat transfer through solid-state phase changes, eliminating environmental concerns associated with high global warming potential refrigerants.
4Productivity
If fans and pumps are used in heat pump systems, then heat and fluid circulation are achieved, but noise signature becomes intrusive
Solution Approach 1:
The SMA and NTE cores provide self-driven fluid circulation through their inherent expansion and contraction during phase transitions. This eliminates the need for external fans and pumps, achieving heat circulation without the noise associated with mechanical driving components.
Solution Approach 2:
The invention replaces mechanical fans and pumps with a passive thermally-driven circulation system. The phase transitions of SMA and NTE materials create natural convection currents and pressure differentials that drive fluid flow, eliminating noise-generating mechanical components while maintaining effective heat circulation.
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 system achieves a substantially higher temperature delta and increased thermal output, enhancing the Coefficient of Performance (CoP) and exergetic efficiency, reducing energy consumption and environmental impact while providing a more efficient heating and cooling solution.
Implementation Method 1
a first Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric core positioned in a housing and adapted to absorb heat and/or store energy in response to a first fluid inputted at a first temperature
Implementation Method 2
adapted to absorb heat and/or store energy
Implementation Method 3
a device is configured to apply stress on the first SMA or NTE core in the housing to cause the SMA or NTE core to undergo a phase change and exothermically release heat/energy
Implementation Method 4
exothermically release heat/energy
Implementation Method 5
energy/heat from the heated SMA or NTE core is transferred in to the fluid
Implementation Method 6
A second fluid at a second temperature (or the continuation of the first fluid at the first temperature in certain cases) is then inputted to the core, and energy/heat from the heated SMA or NTE core is transferred in to the fluid
Implementation Method 7
a second Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE)/elastocaloric core positioned in a cascade arrangement with the first core and configured to change state in response to the fluid temperature exiting the first core
Data Source
AI summary
The invention provides a heat pump system and method comprising a first Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) elastocaloric core positioned in a housing and adapted to absorb heat and store energy in response to a first fluid inputted at a first temperature. The housing is configured to receive the first fluid at a first temperature via an inlet to cause the first SMA or NTE elastocaloric core to change state. A device is configured to apply stress on the first SMA or NTE core in the housing to cause the SMA or NTE elastocaloric core to change state, releasing heat/energy and causing the SMA/NTE to heat up. A second fluid at a higher temperature is inputted and then subsequently heated further as a result of heat transfer. A second Shape-Memory Alloy (SMA) or Negative Thermal Expansion (NTE) or elastocaloric core is positioned in a cascade arrangement with the first core, but exhibiting a higher activation temperature. The higher temperature fluid leaving core 1 is inputted into core 2, resulting in a larger net temperature lift than could be achieved with a single core. In the alternative, in a cooling system, to achieve a lower temperature drop, the second core in the cascade can exhibit a lower activation temperatures than the first core. The cycle focus is on the endothermic stress release component where the SMA/NTE/elastocaloric core absorbs energy from the fluid. The first core results in a fluid stream drop and that then enters the second core with lower activation temperatures, resulting in a further drop of the output fluid during the cooling half of the cycle.