Indoor Light Balancing via Controllable Window Transmittance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional indoor illumination systems face challenges in maintaining consistent lighting levels across spaces due to high daylight contrasts near windows, leading to increased power consumption as existing solutions either block daylight or require additional artificial lighting.

Innovation Solution

An illumination system featuring a window with controllable transmittance and a light guide system, where the transmittance and light throughput are balanced using a control unit, often with sensor feedback, to distribute daylight evenly throughout a space without significant electrical power usage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If a curtain or electrochromic window is used to block strong daylight, then illumination differences near the window are reduced, but the indoor space becomes too dark requiring additional artificial lighting which increases power consumption

Engineering Contradiction:
Improveillumination uniformityVSAvoidpower consumption
Core Design Contradiction:
Illumination intensityVSUse of energy by moving object

Solution Approach 1:

The patent divides the window into multiple independently controllable segments or zones. Each segment can be adjusted separately to control daylight transmission, allowing bright areas near the window to be dimmed while maintaining illumination in deeper indoor spaces, thereby reducing the need for artificial lighting and lowering power consumption.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent employs dynamically adjustable window treatments or electrochromic glass that can change their light transmission properties in real-time. This dynamic control allows the system to adapt to varying daylight conditions and indoor illumination requirements, optimizing the balance between natural and artificial lighting to minimize energy consumption.

Inventive Principle:
Principle #15Dynamics

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 solution provides improved energy efficiency in indoor lighting by minimizing the need for electrical power while maintaining comfortable illumination levels across deep spaces, adapting to local conditions and requirements.

Implementation Method 1

a light guide system arranged for transferring light from at least one light guide input to at least one light guide output

Methodology Applied
Scientific EffectOptical transmission: Optical Fibre

Data Source

PatentEP2082163B1Indoor light balancing
Publication Date: 2014.12.17 CHROMOGENICS AB
  • EP2082163B1 patent drawingFigure 1~3
  • EP2082163B1 patent drawingFigure 2~4
  • EP2082163B1 patent drawingFigure 5

AI summary

An illumination system (1) is based on a window (21) having controllable transmittance and a light guide system (31) arranged for transferring light from a light guide input (33) to a light guide output (34). The light guide output (34) is located in a same space (50) as the window (21), but at a distance from the window (21). The illumination system (1) comprises means for balancing (40) the transmittance of the window (21) and a throughput of the light guide system (31). Preferably, the window (21) is an outer window, the light guide input (33) is arranged for gathering day light and the light guide output (34) is arranged to illuminate an area (52) within sight from the window (21). Preferably the transmittance of the window (21) and/ or the light throughput of the light guide system (31) are controlled. In further preferred embodiments, sensor (61, 64) based controlling is applied. In another aspect a method for illuminating a space (50) having a window (21) with controllable transmittance is presented.