Active temperature control of quartz resonant dew point sensors based on dual surface cooling

The combination of the Peltier cooler and quartz crystal resonator (QCR) is critical for temperature-controlled, quartz resonant dew point sensors. As the environmental parameters continuous to change, the cooling effects on the QCR surface will cause unstable vibration changes for dew point sensing applications. In order to achieve continuous and accurate dew point measurements in a dynamically changing atmosphere, this paper presents a new scheme based on the dual surface cooling by connecting two Peltier coolers to both sides of the QCR using elastic thermal materials. The heat transfer performance and vibration characteristics of the QCR are simulated and analyzed, respectively. Simulation results show optimal parameters of the elastic thermal pad have the dimension of the ring structure with inner diameter of 5.2 mm and outer diameter of 8.6 mm. The prototype sensor is subjected to a dew point measurement test in the external environment with fluctuating conditions and results show the relative error of less than 0.06 degrees C at a cooling rate of 0.02 degrees C/s, which are as good as the commercial products. Furthermore, these data have been theoretically verified to measure the dew point in dynamically changing environments. (C) 2017 Elsevier B.V. All rights reserved.