Tintable Window Predictive Control for Sunlight Penetration Comfort
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Solution Overview
Problem
Electrochromic windows, despite advances in technology, have not realized their full commercial potential due to various issues, including inefficiencies in controlling tint levels for occupant comfort and energy conservation.
Innovation Solution
The implementation of predictive control logic in window controllers that adjusts tint levels based on occupant comfort, energy considerations, and actual irradiance, using modules to determine optimal tint levels and communicate instructions for transitioning tint levels in electrochromic windows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrochromic windows are used to control light transmission, then energy efficiency is improved, but occupant comfort control is insufficient
Solution Approach 1:
The system incorporates sensors that continuously monitor irradiance levels, occupancy presence, and natural light conditions. This feedback is processed by control logic that automatically adjusts the electrochromic window tint levels to optimize both energy efficiency and occupant comfort, resolving the contradiction between energy savings and comfort control.
Solution Approach 2:
The window control system operates autonomously using embedded controllers that self-regulate tint levels based on environmental sensors and occupancy detection. The system performs self-diagnosis and automatic adjustment without requiring manual intervention, thereby improving energy efficiency while maintaining occupant comfort through automated control.
2Loss of energy
If tint levels are darkened to reduce radiant energy, then energy conservation is improved, but natural lighting is reduced
Solution Approach 1:
The system dynamically adjusts tint levels in real-time based on varying environmental conditions such as time of day, season, weather, and occupancy patterns. Rather than using fixed dark states, the electrochromic windows transition through multiple intermediate tint levels to optimize the balance between energy conservation and natural lighting requirements.
Solution Approach 2:
The control system modifies multiple parameters including tint level, transition timing, and duration based on irradiance measurements and occupancy data. By changing these parameters dynamically, the system achieves energy conservation goals while maintaining adequate natural lighting levels through precise control of the electrochromic material's optical properties.
3Measurement precision
If predictive control logic is implemented to account for transition time, then control accuracy is improved, but system complexity increases
Solution Approach 1:
The control system performs preliminary calculations of required tint levels based on predicted future conditions, occupancy schedules, and known transition times of the electrochromic material. By anticipating future states and pre-calculating optimal tint levels, the system achieves high control accuracy while managing complexity through algorithmic prediction rather than reactive adjustment.
4Reliability
If multiple control modules are used to balance comfort and energy, then performance is improved, but device complexity increases
Solution Approach 1:
The system integrates multiple control functions including occupancy detection, irradiance sensing, tint level control, and energy optimization into a single unified control module. By merging these previously separate functions into one integrated system, the patent achieves improved performance through coordinated control while reducing overall device complexity through consolidation of control logic and hardware.
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 effectively manages tint levels to balance occupant comfort and energy efficiency, ensuring that electrochromic windows provide sufficient natural lighting while minimizing energy consumption, meeting or exceeding the performance of reference windows as required by local codes.
Implementation Method 1
Electrochromism is a phenomenon in which a material exhibits a reversible electrochemically-mediated change in an optical property when placed in a different electronic state, typically by being subjected to a voltage change.
Data Source
AI summary
A method of controlling tint of a tintable window to account for occupant comfort in a room of a building. The tintable window is between the interior and exterior of the building. The method predicts a tint level for the tintable window at a future time based on a penetration depth of direct sunlight through the tintable window into the room at the future time and space type in the room. The method also provides instructions over a network to transition tint of the tintable window to the tint level.