Thermal Management System Using Phase Change Material Cells
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Solution Overview
Problem
Current thermal management systems for avionics face challenges in efficiently dissipating peak thermal loads and storing heat during loss of air cooling, leading to reduced reliability and life expectancy of electronic components.
Innovation Solution
A thermally conductive enclosure with a metallic cell wall structure and phase change material within a plurality of cells, where the cell width is less than 5 millimeters and cell wall thickness ranges from 0.25 to 1 millimeter, enhances heat transfer and storage by using a heat pipe or vapor chamber for efficient thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If larger heat sinks with higher thermal mass are used to store heat, then heat storage capacity is improved, but device volume and weight increase
Solution Approach 1:
The patent utilizes phase change materials (PCM) that undergo phase transitions (solid-liquid) at specific temperatures to store and release thermal energy. The PCM is contained within an enclosure that has thermally conductive walls, allowing efficient heat transfer between the avionics and the phase change material. This approach provides high heat storage capacity in a compact volume by leveraging the latent heat of fusion during phase change, rather than relying solely on sensible heat storage in large thermal mass heat sinks.
2Temperature
If conventional heat dissipation strategies are used, then steady state cooling is improved, but peak thermal load management and transient damping are insufficient
Solution Approach 1:
The phase change material provides transient thermal management by absorbing excess heat during peak thermal loads through phase transition (melting), and releasing stored heat during cooling periods. This dampens thermal transients and protects avionics from temperature excursions, improving reliability during both steady-state and transient conditions.
Solution Approach 2:
The phase change material is pre-positioned in thermal contact with the avionics housing, ready to immediately absorb peak thermal loads before they can damage sensitive electronics. The PCM undergoes phase transition in advance of potential thermal damage, providing a buffer against temperature excursions.
3Loss of energy
If air cooling is lost, then active cooling capability is improved, but heat storage time is insufficient without additional thermal mass
Solution Approach 1:
The phase change material stores thermal energy in the form of latent heat during phase transition, providing extended heat storage duration without requiring large amounts of thermal mass. When air cooling is lost, the PCM continues to absorb and store heat through phase change, extending the operational duration before thermal damage occurs, without the need for oversized heat sinks.
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 reduces thermal resistance, enabling faster cooling and efficient heat storage, maintaining component performance and reliability even without air cooling, by minimizing temperature gradients and enhancing thermal conductivity.
Implementation Method 1
a phase change material disposed within the cells and in thermal communication with the cell walls
Implementation Method 2
a metallic cell wall structure disposed within the cavity defining a plurality of cells and in thermal communication with the enclosure
Data Source
AI summary
A system is disclosed. The system includes a thermally conductive enclosure bounding an interior cavity, a metallic cell wall structure disposed within the cavity, in thermal communication with the enclosure, and defining a plurality of cells, and a phase change material disposed within the cells and in thermal communication with the cell walls. The plurality of cells have a cell width less than about 5 millimeters, and the cell wall thickness of the cell wall structure is in a range from about 0.25 millimeter to about 1 millimeter.