Infrared-Reflective Substrate for Window Heat Shielding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional window glasses and heat shielding films fail to sufficiently reduce room cooling loads and temperature increases due to thermal reradiation effects, as they absorb near-infrared radiation but allow far-infrared reradiation, and often have poor durability with low abrasion resistance.
Innovation Solution
A visible light-transmissive and infrared-reflective substrate is designed with a high solar absorbance visible light-transmissive substrate layer and an infrared-reflective layer having a reflective layer and a protective layer with low normal emissivity, reducing solar transmittance and far-infrared reradiation while maintaining durability through a hard coating layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional heat shielding films or green glass are used to absorb and reflect solar radiation, then solar transmittance is reduced and near-infrared penetration is suppressed, but far-infrared reradiation from the heated glass increases room temperature and cooling load cannot be sufficiently reduced
Solution Approach 1:
The invention divides the infrared spectrum into two separate functional layers: one layer specifically targets near-infrared reflection (wavelengths 700-2500nm) while another layer targets far-infrared reflection (wavelengths 2500-50000nm). This segmentation allows independent optimization of each wavelength range, preventing the reradiation problem by reflecting far-infrared before it can reheat the room.
Solution Approach 2:
The invention uses a composite structure combining multiple functional layers with different infrared reflectivity characteristics. The composite includes a first infrared reflective layer (e.g., metal oxide or nitride) and a second infrared reflective layer (e.g., metal fluorosulfonate compound), creating a multi-functional coating system that simultaneously handles near-infrared and far-infrared radiation differently, solving the reradiation issue.
2Object-affected harmful factors
If metal thin film layers are used to reflect infrared rays, then infrared reflectivity is improved, but visible light transmittance decreases and durability against abrasion deteriorates
Solution Approach 1:
The invention applies different material properties to different functional layers: the first infrared reflective layer uses metal oxides or nitrides optimized for near-infrared reflection with acceptable visible transmittance, while the second layer uses metal fluorosulfonate compounds optimized for far-infrared reflection. Each layer is locally optimized for its specific wavelength range, maintaining overall visible light transmittance while achieving comprehensive infrared protection.
Solution Approach 2:
The invention changes the optical parameters of each layer by selecting materials with different refractive indices, absorption coefficients, and reflectivity characteristics for specific wavelength ranges. By controlling layer thickness and material composition, the patent optimizes the balance between visible light transmittance and infrared reflectivity for each functional layer.
3Object-affected harmful factors
If metal deposition layers are used to reflect near-infrared rays, then solar heat gain is reduced, but abrasion resistance decreases and durability worsens
Solution Approach 1:
The invention creates a composite protective system where the first infrared reflective layer (metal oxide or nitride) provides near-infrared reflection and serves as a durable base layer, while the second infrared reflective layer (metal fluorosulfonate compound) provides far-infrared reflection and enhances overall durability. This composite structure achieves both heat rejection and abrasion resistance that neither layer could achieve alone.
Solution Approach 2:
The second infrared reflective layer serves multiple functions simultaneously: it reflects far-infrared radiation, protects the first infrared reflective layer from abrasion, and enhances the overall durability of the coating system. This multi-functionality resolves the contradiction between achieving infrared reflection and maintaining abrasion resistance.
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 substrate effectively reduces reradiation heat and temperature increases inside rooms by minimizing far-infrared reradiation and enhancing abrasion resistance, providing improved heat shielding and insulation properties.
Implementation Method 1
an infrared-reflective layer laminated on a surface on the room side of the visible light-transmissive substrate layer... a reflective layer configured to reflect infrared rays
Implementation Method 2
the visible light-transmissive substrate layer has a solar absorbance of at least 30%... the glass absorbs electromagnetic waves in the near-infrared region contained in solar radiation
Implementation Method 3
all substances radiate electromagnetic waves containing electromagnetic waves in the far-infrared region at about room temperature, and the amount of radiation of electromagnetic waves in the far-infrared region increases as the temperature increases
Data Source
Figure 1
AI summary
Provided is a visible light-transmissive and infrared-reflective substrate, including: a visible light-transmissive substrate layer disposed so as to serve as a partition between inside and outside of a room; and an infrared-reflective layer laminated on a surface on the room side of the visible light-transmissive substrate layer, wherein the visible light-transmissive substrate layer has a solar absorbance of at least 30%, the infrared-reflective layer includes a reflective layer configured to reflect infrared rays and a protective layer laminated on a surface on the room side of the reflective layer, and normal emissivity of a surface on the protective layer side of the infrared-reflective layer is not more than 0.50.