Gas composition determination in an air conditioned system using a sensor array: characterization of three different TGS sensors

The determination of the atmosphere gas composition in any application by g as sensors implies a very well-known response to all the sensors used to ob tain this information. The aim of our work is to detect forane R134a or car bon dioxide or a mixture of these two gases in dry synthetic air. For these reasons, the first studied sensor was the TGS 832 dedicated to forane R134 a. The two other types of sensors chosen for this work are TGS 800 and TGS 813, dedicated respectively to air contaminants and general combustible gas es. In this paper, we present a systematic characterization of two sensors (TGS 800, TGS 813) and compare their behaviour with the behaviour of the TG S 832. Then, we discuss their similarities and oppositions, using them in a n array to discriminate the gas present in an air conditioned system. The l ook-up table constituted by this study is the necessary base to use a patte rn recognition method in order to conclude on the gas nature. (C) 1999 Else vier Science S.A. All rights reserved.