Novel Microthermal Sensor for Quantification of Methanol in Water for Direct Methanol Fuel Cells

摘要

A novel, simple sensor principle for determination of the ratio of fluids in a mixture is investigated. Itrnmakes use of the different thermal properties of the components in the mixture like thermalrnconductivity and heat capacity. Through their determination the ratio of components of binary mixturesrncan be measured if the components are known. When applying a heat pulse the temperature rise afterrna given time is used to determine the mixture ratio. Using microfabricated structures the sensor isrncapable of measuring the mixture ratio with an accuracy of approximately 2% in single shotrnexperiments in less than a second. In Direct Methanol Fuel Cells the sensor can be used in a closedrnloop control of the methanol amount in deionized water to ensure the optimum working point.