Design Of Sensors For Measuring Water Content In Building Envelope And Data Processing

The improvement of thermal insulation performance is one of the important ways to building energy conversation.The change of water content in the building envelope has a crucial effect on testing of the insulation performance. So how to test water content in the building is very important.In this paper, the structure of uniplanar scattering-field capacitive sensor is used according to testing depth and testing feature. On the basis of the study on the theory about the optimization method of the size and structure for the uniplanar scattering-field capacitive sensors ,a series of sensors with different detecting depth for testing water content in the building are designed by simulations and experiments.The improved charge/discharge capacitance measuring circuit is used in these sensors.A lot of experiments are done with the newly designed sensors in order to realize the tomography of the water content distribution of the building envelope. The construction wall is divided into some layers in the direction of depth during the experiments, and the relationship between water content and the output of two probes are drawn by means of numerical analysis. By means of combination measurement, the water content in each layer can be obtained. Results show that the distribution of the water can be calculated from the equations.The software system is developed with Visual C++.Many functions are realized in this sofeware including software digital filtering, water content arithmetic programming,the management of the detecting result,et al.A Real-time System for water content testing is realized.