Wedge-Based Heat Switch Using Phase Transition Material
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Solution Overview
Problem
Existing heat switches face limitations in rapidly switching between thermally conductive and insulating states due to the presence of a solid thermal path, high mass of housing, and slow response times, especially in extreme temperature environments.
Innovation Solution
A wedge-based heat switch utilizing an energy storage element and temperature-activated phase transition material to axially and radially move wedge segments, creating or breaking thermal contact between surfaces, allowing for rapid switching between conductive and insulating states without a solid thermal path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid thermal path is maintained between hot and cold sides in both conductive and insulating states, then thermal contact is ensured, but the heat switching effect is diminished
Solution Approach 1:
The device segments the thermal path by using discrete wedge elements that can be independently positioned to either make or break thermal contact. The wedge is divided into functional zones: a leading edge for initial contact, a body for thermal conduction, and a trailing edge for separation, allowing controlled interruption of the thermal path while maintaining reliability when engaged.
Solution Approach 2:
The invention transitions from a one-dimensional linear motion approach to a two-dimensional wedge geometry that combines axial movement with radial expansion. This dimensional change allows the wedge to simultaneously engage multiple thermal interfaces and create a distributed thermal path, improving both contact reliability and switching effectiveness.
2Stability of the object's composition
If the mass of the housing is large in comparison to the spring, then structural stability is improved, but spring energy available to generate contact pressure is diminished
Solution Approach 1:
The device employs dynamic elements including a spring-loaded wedge mechanism that can rapidly transition between states. The spring provides stored energy for actuation, while the wedge's geometric design allows it to leverage this energy efficiently. The system balances structural stability with dynamic responsiveness, enabling rapid thermal switching without requiring excessive mass.
Solution Approach 2:
The invention changes key parameters including the spring constant, wedge angle, and mass distribution to optimize the balance between structural stability and energy utilization. By adjusting these parameters, the system achieves sufficient structural support while maximizing the spring's ability to generate contact pressure for effective thermal switching.
3Ease of manufacture
If common materials are used for bimetallic strips, then material availability is improved, but deflection is only millionths of an inch per degree temperature change requiring very large size or extreme temperature differences
Solution Approach 1:
The device utilizes phase transition materials that undergo significant dimensional changes at specific temperature thresholds. Unlike conventional bimetallic strips that rely on gradual thermal expansion, the phase transition material provides abrupt, large-magnitude dimensional changes that enable rapid and significant wedge displacement, achieving fast response times without requiring extreme temperature differences or large device sizes.
4Productivity
If wedge segments are moved axially to expand or contract radially, then thermal contact is made or broken, but device complexity increases
Solution Approach 1:
The invention merges multiple functions into the wedge element itself: it serves as both the actuator and the thermal conduction path, eliminates the need for separate thermal interfaces by integrating contact surfaces directly on the wedge, and combines mechanical actuation with thermal management functions. This consolidation reduces overall device complexity while maintaining effective thermal switching capability.
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 rapid and efficient thermal management by creating high contact pressure and maximizing heat transfer while minimizing mass and volume, suitable for applications requiring quick switching between conductive and insulating states.
Implementation Method 1
Shape memory heat switches are based on shape memory materials that undergo a solid-state phase change from martensitic to austenitic crystal structure at a prescribed temperature that commonly yields growth or shrinkage of the material by approximately 3-6%
Implementation Method 2
Differential thermal expansion devices leverage the differences in the coefficient of thermal expansion of two different materials to make and/or break thermal contact between components at a prescribed activation temperature
Data Source
AI summary
A wedge-based heat switch includes a plurality of wedge segments on a shaft, an energy storage element (e.g., a spring or pressurized cavity) configured to store (and release) energy via compression or expansion of the element along the shaft and a temperature activated phase transition material. A temperature stimulus activates the phase transition material to release the stored energy and move the wedge segments axially along the shaft to expand or contract the plurality of wedge segments. The wedge-based heat switch may be configured as a unidirectional switch, either conductive-to-insulating or insulating-to-conductive, or a bi-directional switch. The specific design of the wedge-based heat switch is informed by such factors as unidirectional or bi-directional, required preloading of a surface, conductance ratio between conducting and insulating states, temperature stimulus, switching speed and form factor.