Radiative Cooling Interface for Wearable Electronics
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Solution Overview
Problem
Conventional thermal management techniques for wearable electronic devices, such as conduction and convection, are inefficient for compact, high-power devices, leading to heat accumulation and potential discomfort or injury due to inadequate heat dissipation.
Innovation Solution
A radiative cooling material composed of a polymeric matrix and dispersed materials that reflect solar radiation and emit thermal radiation in specific wavelengths, enhancing cooling efficiency through conduction, convection, and radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional thermal management techniques (conduction and convection) are used for wearable electronic devices, then the device structure remains simple, but heat dissipation efficiency is insufficient leading to heat accumulation
Solution Approach 1:
The patent replaces conventional mechanical thermal management systems (heat sinks, fans, thermal conduits) with a radiative cooling coating that utilizes optical and thermal radiation principles. The coating reflects solar radiation and emits thermal radiation in the atmospheric window region (8-13 μm), enabling passive heat dissipation without mechanical components, thus resolving the contradiction between heat dissipation efficiency and device complexity
Solution Approach 2:
The patent changes the optical and thermal parameters of the device surface by applying a specialized coating with specific solar reflectance (>80%) and thermal emissivity (>0.9 in 8-13 μm region). This parameter change enables the surface to actively manage thermal radiation, significantly improving heat dissipation efficiency without adding complex thermal management structures
2Power
If the wearable device is made compact with high power components, then device functionality is improved, but heat accumulation increases affecting performance and user comfort
Solution Approach 1:
The patent converts the harmful effect of high power density (heat generation) into a beneficial outcome by using the heat radiation itself as the cooling mechanism. The radiative cooling coating is designed to emit thermal radiation in the atmospheric window region, allowing the device to dissipate the heat generated by high power components directly to the cold sky, thus converting the heat problem into an effective cooling solution
Solution Approach 2:
The radiative cooling coating acts as an intermediary between the high power components and the environment. It provides a dedicated thermal radiation pathway that mediates heat transfer from the compact high power components to the atmosphere, preventing heat accumulation and maintaining acceptable operating temperatures despite high power density
3Use of energy by moving object
If solar radiation reaches the wearable device, then the device can be charged by solar energy, but the device temperature increases causing discomfort or injury
Solution Approach 1:
The patent segments the solar spectrum and thermal radiation spectrum into distinct handling zones. The coating reflects the harmful solar radiation wavelengths (0.3-2.5 μm) while allowing solar energy conversion components to function. Simultaneously, it emits thermal radiation in the atmospheric window region (8-13 μm), separating the energy absorption and heat dissipation processes to eliminate the contradiction between solar energy utilization and solar heating prevention
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 radiative cooling material effectively reduces heat accumulation in wearable electronic devices by reflecting solar radiation and emitting thermal radiation, improving thermal management and preventing overheating.
Implementation Method 1
The radiative cooling material is operable to facilitate reflection (e.g., scattering or backscattering) of solar radiation in at least some solar spectrum wavelengths
Implementation Method 2
The radiative cooling material is operable to facilitate reflection (e.g., scattering or backscattering) of solar radiation in at least some solar spectrum wavelengths
Implementation Method 3
The radiative cooling material is operable to facilitate emission of thermal radiation in at least some infrared spectrum wavelengths
Implementation Method 4
The radiative cooling material can be arranged to be in thermal contact with the wearable electronic device, which may become hot during operation, to facilitate its cooling, e.g., by conduction, convection, and radiation
Implementation Method 5
The radiative cooling material can be arranged to be in thermal contact with the wearable electronic device, which may become hot during operation, to facilitate its cooling, e.g., by conduction, convection, and radiation
Data Source
AI summary
A wearable electronic device includes a radiative cooling interface for facilitating cooling of a wearable electronic device. The radiative cooling interface is flexible and is made at least partly of a radiative cooling material that includes a polymeric matrix and one or more materials dispersed in the polymeric matrix. The radiative cooling material is operable to facilitate reflection of solar radiation in at least some solar spectrum wavelengths, when the radiative cooling material is exposed to solar radiation. The radiative cooling material is also operable to facilitate emission of thermal radiation in at least some infrared spectrum wavelengths.