Luminaire Temperature Sensing With Compensation for Occupant-Level Accuracy
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Solution Overview
Problem
Existing HVAC systems face challenges in accurately measuring room temperature, particularly at occupant level, due to issues with wall-mounted sensors, thermal stratification, and interference from heat sources like LEDs, leading to inaccurate and costly infrared sensors.
Innovation Solution
A system using a temperature sensor associated with a luminaire that compensates for heat generated by the luminaire by analyzing temperature changes during status transitions, applying a temperature correction model to adjust readings, and optionally using adjacent sensors for calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If temperature sensors are mounted on ceiling structures or luminaires, then installation ease and cost are improved, but measurement accuracy deteriorates due to thermal stratification and heat conduction from power dissipaters
Solution Approach 1:
The system performs preliminary calibration by measuring temperature during luminaire off-periods and on-periods to establish a baseline relationship between luminaire operation and temperature sensor readings. This preliminary action enables the system to predict and compensate for thermal effects during normal operation without requiring complex hardware modifications.
Solution Approach 2:
The system continuously monitors temperature sensor readings and compares them against calibrated baseline values to detect deviations caused by luminaire heating. This feedback mechanism triggers automatic compensation calculations that adjust the temperature measurement in real-time, maintaining accuracy despite the ceiling-mounted sensor location.
2Adaptability or versatility
If infrared temperature sensors are used to remotely obtain sensor readings, then installation flexibility is improved, but cost and accuracy deteriorate
Solution Approach 1:
Instead of using expensive infrared sensors to directly measure temperature, the system uses a simple contact temperature sensor to measure the thermal state of the luminaire housing. This copied measurement approach, combined with calibration data, provides accurate temperature information without the cost and complexity of infrared technology.
3Measurement precision
If wall-mounted temperature sensors are used, then measurement accuracy for general room temperature is improved, but installation complexity and cost increase
Solution Approach 1:
The system combines the temperature sensing function with the existing luminaire structure, merging two separate functions (lighting and temperature measurement) into a single integrated unit. This eliminates the need for separate wall-mounted temperature sensors and their associated installation complexity while maintaining the ability to measure occupant-level temperature.
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 accurate occupant-level temperature detection with affordable and easy-to-install sensors, correcting for luminaire heating and thermal stratification, improving temperature measurement accuracy.
Implementation Method 1
temperature sensors are affected by thermal conduction and radiation from power dissipaters such as LEDs, drivers, and signal processors
Implementation Method 2
temperature sensors are affected by thermal conduction and radiation from power dissipaters such as LEDs, drivers, and signal processors
Implementation Method 3
temperature sensors located at or near a ceiling would be affected by thermal stratification of the air in the space
Data Source
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AI summary
A method (300) for determining temperature in a region (220/230) of an environment (200) by compensating for heat-up of a temperature sensor caused by ambient air and/or electronic heating, using a system (100) comprising: (i) a structure (110); (ii) a controller (130); and (iii) a temperature sensor (120), the method comprising: obtaining (320) first temperature measurements while the structure is in a first operating mode; changing (330) the first operating mode of the structure to a second operating mode; obtaining (340) second temperature measurements while the structure is in the second operating mode; determining (350) a temperature correction comprising an effect of the second operating mode on the temperature sensor; obtaining (360) a new temperature measurement during operation of the structure in the second operating mode; and adjusting (370), using the temperature correction, the new temperature measurement to generate a compensated temperature measurement.