Radiative cooling device and method of manufacturing the same
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Solution Overview
Problem
Conventional radiative cooling devices are limited to a metallic mirror-like color, which restricts their application and aesthetic appeal, while also facing challenges in achieving efficient cooling without energy consumption.
Innovation Solution
A radiative cooling device with a white radiative cooling layer featuring an uneven pattern and a combination of fine particles and polymers that reflect and scatter visible light, while effectively emitting mid-infrared light, allowing for increased cooling efficiency and various color appearances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metallic mirror-like material is used for radiative cooling, then mid-infrared emissivity is improved, but color variety and aesthetic appeal deteriorate
Solution Approach 1:
The patent combines metallic particles (for mid-infrared emissivity) with polymer matrices and colorants to create composite materials that maintain radiative cooling performance while achieving various colors. The composite structure allows simultaneous optimization of thermal radiation properties and aesthetic appearance.
Solution Approach 2:
The patent applies different materials and structures to different layers or regions of the radiative cooling device. The metallic component is concentrated in specific layers to ensure mid-infrared emissivity, while other layers incorporate colorants and polymers to provide color variety without compromising the overall cooling performance.
2Loss of energy
If a reflective coating is applied to block sunlight, then heat inflow is reduced, but the surface area for mid-infrared radiation is decreased
Solution Approach 1:
The patent divides the radiative cooling device into multiple functional layers: a reflective layer for blocking sunlight and a separate radiative cooling layer with high surface area structure for mid-infrared emission. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The patent introduces surface roughness and three-dimensional structures in the radiative cooling layer to increase the effective surface area for mid-infrared radiation. By transitioning from a flat two-dimensional surface to a three-dimensional textured surface, the device maintains compact form factor while maximizing radiating area.
3Ease of manufacture
If the radiative cooling layer is made smooth and flat, then manufacturing is simplified, but mid-infrared emissivity is reduced
Solution Approach 1:
The patent incorporates porous or textured structures in the radiative cooling layer that can be formed through relatively simple manufacturing processes such as phase separation, foaming, or template-assisted methods. These porous structures increase surface area and enhance mid-infrared emissivity without requiring complex precision manufacturing.
Solution Approach 2:
The patent employs curved or spherical surface features in the radiative cooling layer that can be generated through straightforward techniques like spray coating, dip coating, or self-assembly processes. The curvature increases surface area and improves mid-infrared emission while maintaining manufacturing simplicity.
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 device achieves enhanced cooling performance by maximizing mid-infrared emissivity and visible light reflectance, reducing energy consumption, and offering a range of color options beyond traditional metallic appearances.
Implementation Method 1
When light corresponding to these wavelength ranges is reflected, inflow of heat through sunlight may be blocked
Implementation Method 2
A radiative cooling device with a white radiative cooling layer featuring an uneven pattern and a combination of fine particles and polymers that reflect and scatter visible light
Implementation Method 3
All objects emit heat to the outside in the form of light, and the wavelength band of the emitted light is determined by the surface temperature of the objects
Implementation Method 4
A material having a surface temperature of several tens of degrees C. emits mid-infrared light with a wavelength of several tens of micrometers to the outside
Implementation Method 5
due to increase in the surface area of the radiative cooling layer due to the presence of the uneven pattern, the mid-infrared emissivity of the radiative cooling device may be increased
Data Source
AI summary
A radiative cooling device, and a method of manufacturing the same, includes a reflective layer disposed on a substrate and responsible for reflecting sunlight having wavelengths corresponding to ultraviolet, visible, and near-infrared regions; and a radiative cooling layer disposed on the reflective layer and responsible for absorbing sunlight having a wavelength corresponding to a mid-infrared region and emitting the sunlight as heat, wherein the radiative cooling layer includes a first radiation layer including an uneven pattern; and a second radiation layer disposed on the first radiation layer and having a refractive index different from that of the first radiation layer.