Self-Calibrating Daylighting Controller with Adaptive Setpoint
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing daylighting systems face challenges in maintaining energy savings, responding to changing room conditions, and sensor placement restrictions, particularly in dynamic environments like offices and classrooms, where user-adjustable light levels and seasonal changes affect light sensor calibration and accuracy.
Innovation Solution
The system dynamically recalibrates the light sensor by capturing a new daylighting setpoint each time the light level is adjusted by the user, integrating user feedback to compensate for changing conditions such as glare, lamp color, and surface reflectance, and allows for intuitive operation with minimal maintenance, enabling daylighting at all user settings and reducing sensor placement complexities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a fixed setpoint is used with ceiling-mounted light sensors, then sensor placement is simplified and protection is improved, but the system cannot respond to changing room conditions and user needs
Solution Approach 1:
The system dynamically adjusts the daylighting setpoint based on user preferences and changing conditions. Instead of using a fixed setpoint, the controller continuously adapts the target light level to match user needs and environmental changes, allowing the ceiling-mounted sensor to effectively control daylighting in dynamic environments.
Solution Approach 2:
The system incorporates user feedback through preference inputs and occupancy detection. The controller uses this feedback to adjust the daylighting setpoint and control strategy, enabling the ceiling-mounted sensor system to respond to changing room conditions and user needs while maintaining the simplicity of ceiling installation.
2Measurement precision
If work surface sensor placement is used, then accurate local light level measurement is achieved, but the sensor is inaccessible to users and requires maintenance intervention for recalibration
Solution Approach 1:
The system performs self-calibration by using user light level preferences as reference points. When users adjust lighting to their preferred levels, the system automatically learns and adapts to the optimal daylighting setpoint for that location, eliminating the need for manual maintenance recalibration while maintaining measurement accuracy.
Solution Approach 2:
The ceiling-mounted light sensor serves multiple functions: it measures ambient light levels for daylighting control, provides occupancy detection capability, and enables user preference learning. This multi-functionality compensates for the indirect measurement approach, allowing a single accessible location to handle various control needs without requiring maintenance intervention.
3Measurement precision
If daylighting control is suspended during user adjustments, then accurate setpoint capture is enabled, but energy savings are temporarily reduced during adjustment periods
Solution Approach 1:
The system suspends daylighting control only temporarily during user adjustment periods to capture accurate setpoint information. This partial suspension is necessary to learn user preferences and adapt to changing conditions. The brief interruption is outweighed by the long-term energy savings achieved through accurate adaptation to user needs and environmental changes.
Data Source
AI summary
A method and means for creating a daylight harvesting controller with a self calibrating light sensor and an adaptive setpoint that maintains a user determined light level is disclosed herein. The system includes a light sensor for monitoring the ambient light level of a designated control zone and a means to receive and interpret light level adjustment commands created by a user or user surrogate. The system includes means to limit the setpoint to a maximum value, suspend daylighting activity when lights are being adjusted or are turned off, and to delay setpoint capture and the start or resumption of daylighting until an adjustment cycle is completed and the zone light sources have reached a nominally steady state.