Predictive Tint Control for Electrochromic Windows in Buildings
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Solution Overview
Problem
Electrochromic devices, particularly electrochromic windows, have not realized their full commercial potential due to various issues such as inefficiencies in controlling tint levels for occupant comfort and energy conservation, despite advances in electrochromic technology.
Innovation Solution
The implementation of predictive control logic for electrochromic windows that adjusts tint levels based on occupant comfort, energy considerations, and actual irradiance conditions, using modules that account for penetration depth of sunlight, space type, and energy savings requirements, with a system comprising a processor, pulse width modulator, and sensors to dynamically control tint levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If electrochromic windows are used to control tint levels, then energy savings and occupant comfort can be improved, but inefficiencies in controlling tint levels reduce the realization of full commercial potential
Solution Approach 1:
The patent implements a control system that uses sensors to detect actual irradiance conditions and provides feedback to the controller, which then adjusts the tint level of electrochromic windows accordingly. This closed-loop feedback mechanism ensures optimal energy savings by dynamically responding to changing environmental conditions, thereby resolving the inefficiency that prevents full commercial potential realization.
Solution Approach 2:
The control system predicts future irradiance conditions and preemptively adjusts tint levels before peak sunlight exposure occurs. This preliminary action allows the system to prepare for upcoming high-irradiance periods, maximizing energy savings by reducing heat gain before it occurs, rather than reactively responding after the fact.
2Object-affected harmful factors
If tint levels are adjusted to reduce glare for occupant comfort, then occupant comfort is improved, but the control efficiency and energy savings may be compromised
Solution Approach 1:
The patent implements zone-based control that allows different tint levels in different areas of the building based on local conditions. The system can apply stronger tinting in zones where glare is detected while maintaining lighter tinting in zones where natural light is desired, thereby achieving glare reduction without unnecessarily compromising overall control efficiency or energy savings.
Solution Approach 2:
The control system dynamically adjusts tint levels based on real-time sensor data regarding glare conditions, occupancy patterns, and irradiance levels. This dynamic adjustment allows the system to optimize the balance between glare reduction and energy efficiency continuously, rather than using static pre-programmed settings, thereby maintaining high control efficiency while improving occupant comfort.
3Loss of energy
If predictive control logic is implemented to account for penetration depth and space type, then occupant comfort and energy savings are improved, but device complexity increases
Solution Approach 1:
The patent divides the building into multiple zones with different space type classifications (e.g., occupied zones, transitional zones, core zones). Each zone has its own control parameters and penetration depth calculations tailored to its specific characteristics. This segmentation allows the complex predictive control logic to be broken down into manageable zone-specific modules, improving energy savings through targeted control while making the overall system complexity more manageable through modular design.
4Measurement precision
If multiple sensors and modules are used to monitor irradiance and control tint levels, then measurement precision and control accuracy are improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple sensing functions into integrated sensor modules that can measure various parameters (irradiance, temperature, occupancy) simultaneously. By merging these functions into unified sensor units rather than using separate components, the system achieves high measurement precision for irradiance while reducing overall device complexity and component count, thereby lowering system cost without sacrificing accuracy.
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 enables effective control of tint levels in electrochromic windows to enhance occupant comfort by reducing glare and allowing natural lighting while ensuring energy savings that meet or exceed those of reference windows, thereby improving the energy efficiency of buildings.
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. The optical property is typically one or more of color, transmittance, absorbance, and reflectance.
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 lighting received 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.