Research on Water Vapor Release and Adsorption Mechanism to Improve the Measurement of Dew Point Humidity Sensor

Abstract

To improve the measurement accuracy of the dew point humidity sensor (sensor), starting from the problem of water vapor release and adsorption during the temperature change and based on tunable diode laser absorption spectroscopy (TDLAS), the experimental environment is designed and built with an embedded water content tester (tester), low temperature dew point generator (dew point generator), MBW humidity standard device (standard device), variable temperature freezer refrigerator (variable temperature box) and other equipment. The water vapor release effect of the sensor when the ambient temperature rises and the water vapor adsorption effect when the ambient temperature decreases are verified, and the degree of water vapor release and adsorption effects under different temperature changes, different water vapor concentrations, and different flow rates are quantitatively measured. The results show that the greater the temperature change is, the greater the release and adsorption of water vapor; the greater the concentration of water vapor is under the same temperature change, the greater the release and adsorption of water vapor; and the greater the gas flow is, the less obvious the release and adsorption of water vapor. The water vapor release and adsorption under different water vapor concentrations, different starting temperature points, and different temperature changes in the gas path are calculated. Subsequently, a reference table of sensor variable temperature compensation coefficients is given, which provides a new way to further improve the accuracy of sensor measurement.