ELMINA: Elektronische Mikronasen für überwachungs- und Regelaufgaben in Gebäuden und Produktionsanlagen: Abschlussbericht des HGF-Strategieprojektes

Abstract

Aim. The ELMINA project aimed at the development of a new generation of electronic noses - designed as compact modules on the basis of highly integrated micro systems, combining high analytical performance and reliabilitywith low energy consumption, inexpensive price and little spatial requirements. These modules are meant to demonstrate the feasibility of intelligent functions for monitoring and controlling industrial production or the household, without causing any substantial additional costs, spatial requirements or energy consumption. Considering the complexity of buildings or production facilities, the development of a network of ENs is required as it shows the greatest potential for multi-location monitoring, for instance for locating the emission sources, watching the spreading and predicting the dissemination of gases or odours. Benefit. Continuous monitoring and control with electronic noses (EN) provides the basis for numerous intelligent processes and products, allowing self-regulated and economic energy and material consumption, inherent environmental protection, higher safety in buildings and last but not least process control for greater stability and higher quality in industrial fabrication. Automation and enhanced functionality further leads to a higher user-friendliness. In addition to the innovative potential for devices or facilities that already employ gas analysis, a wide range of novel gas analytical applications are now becoming feasible thanks to the substantial progress in gas analytical power, in reducing the space requirements, lowering the power consumption and shrinking the expenditure, obtained with the novel electronic nose modules. Realization. Two measurement principles have been implemented individually and in combination: the gas sensitive conductivity of semi-conducting metal oxides and the gas dependence of the velocity of surface acoustic waves on appropriate polymer materials. Based on the two instruments developed at the Institute of Instrumental Analysis, - the Karlsruhe Micronose KAMINA with its unique metal oxide gradient microarray and the SAW Aroma and Gas Analysis System SAGAS that works with acoustic surface waves - a new EN generation has been developed which is much smaller and more compact and which has a higher gas analytical performance and a lower power consumption than the EN generation before. Moreover, a combi-version of the two EN types (SAMONA) has been designed that merges the two partly complementary techniques into one EN instrument of even further enhanced analytical power. Reconstruction and down sizing of the micro structures, new chemical equipment of the microsensor systems, improved manufacturing technique, novel packaging, more compact operating electronics with improved circuitry, a largely extended multivariate data analysis for online application and a new sampling arrangement have contributed to the great performance leap for EN modules. For multi-location monitoring with a net of ENs, an intelligent network software has been developed, capable of collecting, visualizing and storing the data online and furthermore capable of determining the spatiotemporal spreading of the gases or odours. Exemplary Applications. Development was focused on three representative areas of application: Indoor air monitoring (air quality control and fire alarm) with the KAMINA, natural gas analysis and monitoring storehouses for chemicals - potential application fields of both sensor systems and especially of the combi system SAMONA. KAMINA-System Advances. A novel KAMINA chip was designed, bearing 16 sensor segments and 2 temperature sensors on an area of 3*3.5 mm 2 only. With an operating temperature of 300°C, heating capacity could be reduced to < 1 W. The use of Al 2 O 3 as new substrate material means lower thermal conduction and thus enables higher temperature differentiation between the individual sensor segments compared to the previously used substrate material Si/SiO