Phase-Change Thermal Control Material for Passive Emissivity Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing thermal control systems in environments with large temperature fluctuations, such as space, are bulky and require power due to their reliance on mechanically-moving parts or fluid-filled heat pipes, and lack switchable emissivity for efficient temperature regulation.
Innovation Solution
A thermal control material utilizing a multilayer structure with a substrate, a solid-state phase change material, and a reflective layer that passively adjusts emissivity based on temperature changes, leveraging a thermally-actuated metal-insulator phase transition in vanadium dioxide to enhance or reduce thermal radiation as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If mechanically-moving parts or fluid-filled heat pipes are used for thermal control, then temperature regulation capability is improved, but device weight and complexity increase
Solution Approach 1:
The patent replaces mechanically-moving parts and fluid-filled heat pipes with a solid-state phase change material system. The vanadium dioxide material undergoes a metal-insulator phase transition at approximately 68°C, changing its thermal emissivity properties without any mechanical movement or fluid circulation, thereby eliminating the need for bulky mechanical components while maintaining temperature regulation capability
Solution Approach 2:
The patent utilizes the metal-insulator phase transition of vanadium dioxide at approximately 68°C to achieve switchable thermal emissivity. Below the transition temperature, the material exhibits high emissivity for thermal radiation; above the transition temperature, it exhibits low emissivity. This phase transition enables passive temperature regulation without mechanical components or external power
2Temperature
If mechanically-moving parts or fluid-filled heat pipes are used for thermal control, then temperature regulation capability is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent replaces mechanically-moving parts and fluid-filled heat pipes with a solid-state phase change material system. The vanadium dioxide material undergoes a metal-insulator phase transition at approximately 68°C, changing its thermal emissivity properties without any mechanical movement or fluid circulation, thereby eliminating the need for bulky mechanical components while maintaining temperature regulation capability
Solution Approach 2:
The phase change material system is self-regulating and requires no external power or control systems. When the temperature rises above the transition point, the material automatically switches to low-emissivity state to retain heat; when temperature drops below the transition point, it automatically switches to high-emissivity state to radiate heat away, providing autonomous temperature stabilization
3Loss of energy
If fixed emissivity radiators are used, then thermal radiation emission is achieved, but switchable emissivity for efficient temperature regulation is lost
Solution Approach 1:
The patent utilizes the metal-insulator phase transition of vanadium dioxide at approximately 68°C to achieve switchable thermal emissivity. Below the transition temperature, the material exhibits high emissivity for thermal radiation; above the transition temperature, it exhibits low emissivity. This phase transition enables passive temperature regulation without mechanical components or external power
Solution Approach 2:
The patent changes the thermal emissivity parameter of the radiator surface by utilizing the phase transition properties of vanadium dioxide. The material's emissivity dynamically adjusts based on temperature: high emissivity below 68°C for effective radiative cooling, and low emissivity above 68°C to minimize heat loss, enabling efficient temperature regulation across different thermal conditions
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
Provides efficient, lightweight, and power-free thermal regulation by passively adjusting emissivity, maintaining stable temperatures under dynamic thermal loads, suitable for space applications.
Implementation Method 1
a solid state phase change material in contact with the surface
Implementation Method 2
leveraging a thermally-actuated metal-insulator phase transition in vanadium dioxide
Implementation Method 3
passive, steady-state radiative cooling
Implementation Method 4
the absence of convection makes radiative emission the sole cooling mechanism
Implementation Method 5
a reflective thin film material on an opposite side of an optical cavity from the substrate
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
Systems and methods are provided for protecting a temperature sensitive object. A system includes a temperature sensitive object and a thermal control material in thermal communication with the temperature sensitive object. The thermal control material has an emissivity that varies as a function of temperature, and includes a substrate comprising a first surface comprising one of a photonic crystal, a metamaterial, a metasurface, and a multilayer film, a solid state phase change material in contact with the surface, and a reflective thin film material at one of a second surface of the substrate, at a surface of the solid state phase change material, and on an opposite side of an optical cavity from the substrate.