Humidity Sensor Temperature Compensation via Saturation Pressure Ratio
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Solution Overview
Problem
Temperature increases within building automation system wall mount cases can lead to inaccuracies in humidity sensor readings due to elevated internal temperatures, causing errors in measuring relative humidity.
Innovation Solution
A temperature-compensated humidity sensor arrangement that includes an internal humidity sensor and an external temperature sensor, with a processor to calculate and apply a corrective value based on the ratio of saturation pressures at internal and external temperatures, and a time-based filter to align sensor readings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sensors and electronics are integrated in a wall mount case, then multi-variable sensing capability is improved, but internal temperature increases causing humidity sensor measurement errors
Solution Approach 1:
A thermal coupling element (heat sink or heat pipe) is introduced as an intermediary between the electronics and the humidity sensor. This mediator actively manages heat transfer, conducting heat away from the sensor while maintaining thermal equilibrium, thereby decoupling the thermal influence of electronics from the sensitive humidity measurement chamber.
Solution Approach 2:
The system dynamically adjusts operational parameters including sampling timing (synchronized with HVAC cycles), measurement frequency, and thermal compensation algorithms based on detected temperature variations. This allows the sensor system to adapt to changing thermal conditions and maintain accuracy despite temperature fluctuations in the wall mount case.
2Loss of energy
If electrical and thermal design measures are implemented to minimize heat increase, then energy consumption increases, but humidity sensor compensation is still required
Solution Approach 1:
The system incorporates continuous temperature monitoring via integrated temperature sensors and implements real-time feedback through microcontroller-based compensation algorithms. The measured temperature data feeds into saturation pressure calculations and corrective factor applications, creating a closed-loop system that automatically adjusts humidity readings based on actual thermal conditions without requiring additional energy-intensive cooling measures.
Solution Approach 2:
The patent replaces mechanical/physical heat management solutions (such as active cooling systems, thermal isolation chambers, or phased-array heating) with computational methods. Software-based temperature compensation algorithms calculate corrective factors based on measured temperature and apply mathematical transformations to humidity sensor outputs, substituting complex physical thermal management with simpler computational processing.
3Measurement precision
If temperature compensation algorithms are applied, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple functions into integrated components: the wall mount case serves as both structural housing and thermal management element; temperature sensors are integrated directly with the humidity sensor assembly; and the microcontroller handles multiple tasks including temperature compensation, humidity calculation, and data communication. This consolidation reduces overall system complexity while maintaining compensation accuracy.
Solution Approach 2:
The system employs simplified parameter transformation methods, using lookup tables for saturation pressure values and pre-calibrated correction factors based on typical wall mount case thermal characteristics. This approach avoids complex real-time calculations while achieving adequate compensation for standard installation scenarios, reducing computational and algorithmic complexity.
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 configuration effectively compensates for temperature-induced errors, providing accurate relative humidity measurements even in dynamic environments with air flow and electronic heating, reducing inaccuracies and improving sensor reliability.
Implementation Method 1
determining a first saturation pressure for the first sensor and a second saturation pressure for the second sensor. The function comprises a corrective value based on a ratio between the first saturation value and the second saturation value
Implementation Method 2
a second temperature sensor for measuring temperature of the mixture at a point exterior to the chamber
Data Source
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AI summary
A humidity sensor arrangement for providing temperature compensated measurements. A first sensor is configured internal to a housing for the sensor arrangement, and a second sensor is configured external to the housing. The first sensor measures a first relative humidity at a first temperature, and the second sensor measures second temperature external. A processor determines saturation pressures for the first and second sensors and compensates the first sensor by adjusting the relative humidity for the first sensor to be a product of the relative humidity for the first sensor and a ratio of the saturation pressure of the first and second sensors. Further compensation may be produced by applying a time-based filter algorithm to the outputs of the first and second sensors. Temperature sensors can be compensated to determine room temperature and compensated temp can be used for precise humidity compensation.