Smart Window Air-Layer Tuning for NIR Reflection and Visibility
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Solution Overview
Problem
Existing smart windows struggle with controlling solar radiation transmittance and reflectance, leading to energy inefficiencies and visibility issues, with prior technologies being passive and limited in functionality.
Innovation Solution
A smart window design with multiple transparent layers, including a variable air layer, allows for active control of near-infrared radiation by varying the thickness of the air layer, maintaining visible light transmittance while switching between transmissive and reflective modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the transmittance of solar radiant energy is adjusted, then energy efficiency is improved, but visibility varies
Solution Approach 1:
The patent segments the solar spectrum into different wavelength bands (visible light and near-infrared radiation) and applies different control mechanisms to each band. The smart window structure selectively transmits visible light while controlling near-infrared radiation, allowing independent optimization of visibility and energy efficiency.
Solution Approach 2:
The patent applies local quality by creating regions with different optical properties within the smart window structure. Certain layers or coatings are designed to have specific transmittance characteristics for particular wavelength ranges, enabling selective control of different portions of the solar spectrum at different locations within the window structure.
2Adaptability or versatility
If passive temperature-dependent switching is used, then transmissive and reflective modes are achieved, but active electrical control is unavailable
Solution Approach 1:
The patent transitions from static, passive temperature-dependent switching to dynamic, active electrical control. The smart window incorporates electrical signaling capability that allows real-time, on-demand switching between transmissive and reflective modes regardless of temperature conditions, providing flexible and responsive control.
Solution Approach 2:
The patent replaces the passive thermal-mechanical switching mechanism with an active electrical control system. Instead of relying on temperature-induced material property changes, the system uses electrical signals to actively control the switching between modes, enabling precise and timely response to control commands.
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 effectively manages solar radiation energy flow, reducing heating and cooling loads while maintaining constant visibility, enhancing energy efficiency in buildings and vehicles.
Implementation Method 1
as the thickness of the air layer is changed, the near-infrared wavelength of the incident sunlight may be transmissive or reflective
Implementation Method 2
The smart window may switch between the reflective mode and the transmissive mode in a near-infrared rays and may selectively block a solar radiation energy
Data Source
Figure 1~2A
Figure 2B~2C
Figure 3A
AI summary
A smart window is switchable between a transmissive mode and a reflective mode, and includes first, second, third and fourth layers sequentially stacked. The air layer is disposed between the second and third layers. The first, second, third and fourth layers and the air layer are transparent in visible and near-infrared wavelengths of incident sunlight. A thickness of the air layer is variable.