Window Shade Fabric Brightness Factor Selection
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Solution Overview
Problem
Current window shade selection methods do not adequately consider the relative brightness of fabrics under solar lit conditions, which affects personal comfort and energy efficiency, particularly with the increasing use of high visual light transmission glass that leads to increased solar radiant components and glare issues.
Innovation Solution
A system and method to determine a brightness factor for window shade fabrics by incorporating openness factor, visible light reflectance, and visible light transmission, allowing for the comparison and selection of fabrics based on desired interior lighting characteristics and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high visual light transmission glass is used to allow more natural daylight into the building, then daylighting and view are improved, but glare and solar radiant component increase
Solution Approach 1:
The patent applies parameter changes by introducing a brightness factor that incorporates multiple parameters including openness factor, visible light reflectance, visible light transmission, and solar radiant component. By changing the selection criteria from simple light transmission to a composite brightness factor, the system resolves the contradiction by enabling designers to select fabrics that optimize daylighting while controlling glare through balanced parameter consideration.
Solution Approach 2:
The brightness factor serves as an intermediary parameter that mediates between the conflicting requirements of high daylight transmission and glare control. It integrates multiple fabric properties into a single comprehensive metric that reflects both beneficial (daylighting) and harmful (glare, solar radiant) effects, allowing for balanced fabric selection.
2Loss of energy
If high visual light transmission glass is used to reduce artificial lighting and A/C energy usage, then energy efficiency is improved, but HVAC systems are not sufficiently adjusted for the substantial gain in VLt
Solution Approach 1:
The patent introduces feedback mechanisms by providing designers with comprehensive brightness factor data that includes solar radiant component and other critical parameters. This feedback information enables informed fabric selection that anticipates thermal and lighting conditions, allowing HVAC systems to be properly sized and adjusted for the actual performance of the glazing-fabric combination rather than relying on incomplete historical data.
3Object-affected harmful factors
If lighting designers focus on controlling brightness ratios in the field of view to reduce glare, then visual comfort is improved, but the relative brightness of fabrics under solar lit conditions is not adequately considered
Solution Approach 1:
The patent resolves this information loss by fundamentally changing the parameter set used to evaluate fabrics. Instead of relying on incomplete traditional metrics, it introduces the brightness factor that incorporates openness factor, visible light reflectance, visible light transmission, and solar radiant component. This comprehensive parameter approach ensures that fabric brightness under solar lit conditions is accurately captured and considered in the design process.
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
Enables the optimization of daylighting, reduction of artificial lighting needs, and minimization of glare conditions by selecting the appropriate window shade fabric, enhancing visual comfort and energy efficiency while accounting for changes in glazing and environmental conditions.
Implementation Method 1
The brightness factor incorporates the openness factor of the fabric, visible light reflectance of the fabric and visible light transmission of the fabric
Implementation Method 2
The brightness factor incorporates the openness factor of the fabric, visible light reflectance of the fabric and visible light transmission of the fabric
Data Source
AI summary
A system and method for determining a brightness factor associated with a window shade fabric is disclosed. The brightness factor incorporates the openness factor of the fabric, visible light reflectance of the fabric and visible light transmission of the fabric. The brightness factor helps to determine the optimum window shade fabric for a particular room, building or other location. The brightness factor information may be used to select the correct fabric based on desired interior function, light level, the relative surface brightness, and/or any other desired interior characteristic. The fabric selection may affect the building envelope by, for example, facilitating the optimization of daylighting, reduction of artificial electric lighting needs, and minimization of glare conditions.