Thermal Tuning Glazing Using Cholesteric Liquid Crystal
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Solution Overview
Problem
Traditional windows lack dynamic control over solar radiation, leading to inefficient energy usage in both hot and cold weather, as they either block heat and light equally or require electrical power for temperature-dependent light transmission, resulting in increased energy consumption and installation costs.
Innovation Solution
A thermal tuning glazing structure utilizing a cholesteric liquid crystal panel with a temperature-dependent reflection band that shifts between 200 nm and 1 μm, allowing for selective reflection or transmission of sunlight without electrical power, maintaining a see-through view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-E coating is applied to reduce solar heat gain coefficient, then heat gain in summer is reduced, but beneficial heat gain from sun radiation in winter is also reduced
Solution Approach 1:
The patent applies a cholesteric liquid crystal layer that dynamically changes its optical properties in response to temperature variations. At different temperatures, the liquid crystal adjusts its pitch to selectively reflect or transmit specific wavelengths of solar radiation, enabling the window to adapt to seasonal changes without electrical power.
Solution Approach 2:
The invention utilizes temperature-dependent changes in the cholesteric liquid crystal's pitch parameter to modulate its reflection band. As temperature changes, the pitch changes, causing the reflection band to shift and thereby controlling the transmission of solar radiation across different seasons and times of day.
2Adaptability or versatility
If electrical switchable liquid crystal devices are used to control light transmission, then dynamic control of solar radiation is achieved, but electrical wiring cost and complexity increase
Solution Approach 1:
The cholesteric liquid crystal layer serves itself by automatically responding to temperature changes without requiring external electrical control. The material's intrinsic thermotropic properties enable it to adjust its pitch and optical characteristics in response to the ambient temperature, eliminating the need for electrical wiring and control systems.
Solution Approach 2:
The invention replaces the electrical control mechanism with a thermal response mechanism. Instead of using electric fields to control liquid crystal orientation, the system uses temperature-induced changes in the cholesteric pitch to achieve the same light transmission control function.
3Adaptability or versatility
If dichroic dye guest-host device is used to control light transmission, then electronic tuning of light transmission is achieved, but temperature of the thin film becomes very high and dye degrades
Solution Approach 1:
The invention exploits the thermotropic phase transition behavior of cholesteric liquid crystals. As temperature changes, the liquid crystal undergoes phase transitions that alter its pitch and optical properties, enabling dynamic control of light transmission without the high temperatures and degradation issues associated with dichroic dye devices.
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 structure effectively reduces energy consumption by dynamically controlling electromagnetic radiation, optimizing energy savings in both hot and cold conditions while allowing for illumination and visibility without electrical power, thus minimizing heating and cooling loads.
Implementation Method 1
a first cholesteric liquid crystal (CLC) panel, the first CLC panel comprising a first CLC material, the first CLC material being in a first planar texture at least at one temperature, and having a reflection band, wherein the first planar texture has a pitch that changes when temperature varies
Implementation Method 2
selectively reflecting electromagnetic radiation
Data Source
AI summary
Disclosed are thermal tuning glazing structures for selectively reflecting electromagnetic radiation for use in dynamically controlling electromagnetic radiation flow in various applications such as intelligent energy saving windows. The thermal tuning glazing structure comprises one or more cholesteric liquid crystal (CLC) panels, each CLC panel comprising a CLC material, the CLC material being in a planar texture at least at one temperature, having a pitch that changes with temperature, and having a broad reflection band.