A MISiCFET based gas sensor system for combustion control in small-scale wood fired boilers

A novel sensor system based on Metal Insulator Silicon Carbide Field Effect Transistor (MISiCFET) gas sensors has been developed, which is cheap and simple enough for finding its use in combustion control applications e.g small-scale wood fired boilers. The system comprises two Pt gate MISiCFET sensors, utilizing the CO adsorption and oxidation kinetics on Pt, and a thermocouple. The sensor system has been tested in a 40 kW household boiler and the sensor signals compared to flue gas 02, CO, and total hydrocarbon concentrations (THC). The results were in good agreement with theory and the sensor system was shown to give a good estimate of the emissions situation as well as its cause (deficiency or too much of excess air) Its performance regarding the control of the combustion process was also tested and showed good results in terms of lower emissions, enabling the construction of a cheap control system.