Variable Transmittance Window Thermal Control via Dynamic Light Adjustment

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Solution Overview

Problem

Variable transmission windows in vehicles face challenges with thermal energy accumulation, leading to elevated temperatures due to limited thermal convection in multi-pane window assemblies, causing discomfort and potential overheating.

Innovation Solution

A control system that monitors temperature and associated conditions using sensors and current draw to adjust the transmittance of electro-optic elements, increasing light transmittance to dissipate thermal energy and prevent excessive temperature buildup, comprising a window control unit with local and master control circuitry, user input mechanisms, and sensors to manage temperature dynamically.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If multi-pane window assemblies are used to provide insulation and structural integrity, then thermal insulation and strength are improved, but thermal convection is limited causing thermal energy accumulation and elevated temperatures

Engineering Contradiction:
Improvetemperature controlVSAvoidthermal energy accumulation
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting the transmittance of electro-optic elements in response to temperature conditions. When temperature exceeds a threshold, the system changes the optical parameters of the window to increase transmittance, allowing thermal energy to escape. This resolves the contradiction by making the window's thermal properties dynamic rather than static, enabling both insulation when needed and heat dissipation when temperatures become excessive.

Inventive Principle:
Principle #35Parameter changes

2Temperature

If transmittance is increased to dissipate thermal energy, then temperature control is improved, but light transmittance and privacy control are reduced

Engineering Contradiction:
Improvetemperature dissipationVSAvoidlight transmittance
Core Design Contradiction:
TemperatureVSIllumination intensity

Solution Approach 1:

The patent implements dynamics by creating a temperature-responsive control system that automatically adjusts the transmittance of electro-optic elements based on real-time temperature monitoring. The system transitions the window between different transmittance states dynamically - maintaining high transmittance for privacy and heat rejection when cool, and increasing light transmittance when heating is required to dissipate thermal energy. This dynamic behavior resolves the contradiction by making the window adaptive to thermal conditions rather than fixed.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If electro-optic elements are used to control transmittance, then transmittance control is improved, but thermal energy dissipation capability is limited due to the multi-pane structure

Engineering Contradiction:
Improvetransmittance controlVSAvoidthermal convection
Core Design Contradiction:
Ease of operationVSLoss of energy

Solution Approach 1:

The patent applies feedback by implementing a temperature monitoring system that continuously measures thermal conditions and uses this information to control the transmittance of electro-optic elements. When temperature sensors detect excessive heat accumulation, the feedback loop triggers increased transmittance to allow thermal energy to escape through the window assembly. This feedback mechanism resolves the contradiction by enabling the electro-optic elements to actively participate in thermal energy dissipation based on real-time thermal conditions.

Inventive Principle:
Principle #23Feedback

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

Effectively controls the temperature of variable transmission windows by adjusting transmittance, preventing overheating and ensuring comfortable operating conditions, while allowing user control over light levels.

Implementation Method 1

an electro-optic element (22) positioned between a first window pane (18a) and a second window pane (18b)

Methodology Applied
Scientific EffectElectro-optic effect: Electro-Optic Effects

Implementation Method 2

thermal convection in multi-pane window assemblies, causing discomfort and potential overheating

Methodology Applied
Scientific EffectThermal convection: Convection

Data Source

PatentEP3475109B1Thermal control of variable transmittance windows
Publication Date: 2021.04.14 GENTEX CORP
  • EP3475109B1 patent drawingFigure 1
  • EP3475109B1 patent drawingFigure 2
  • EP3475109B1 patent drawingFigure 3

AI summary

An electrical control system for controlling a variable transmittance window is disclosed. The system comprises a driver circuit in communication with an electro-optic element. A controller is in communication with the driver circuit. The controller is configured to identify a temperature condition of the electro-optic element and adjust an output voltage supplied to the electro-optic element in response to the temperature condition.