||Design af DMFC-system til mobile applikationer
||Bang-Møller, Christian (Thermal Energy Systems, Department of Mechanical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Vium, Johan Ådne Hardang
||Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
||IRD A/S is the leading company in Denmark within research, development and production of PEM-based direct methanol fuel cells (DMFC) and DMFC-based systems. As a part of a strategy with production of total solutions IRD A/S has a great deal of interest in the development of a portable
DMFC-based power module. As a contribution to the development of such a power module, this master thesis incorporates system design, thermodynamic modelling, component dimensioning/identification and experimental
research of the functionality and methanol emissions, in relations to this power module.
The system design covers the total power module including fuel cell system and electrical system. The fuel cell system consists of a DMFC stack with auxiliary equipment necessary for operation. The electrical system consists of measuring equipment and electronics for control and monitoring, electrical connections for components and possible hybrid operation.
The system layout has emerged from preliminary considerations of system design along with thermodynamic
modelling. The functionality of the fuel cell system has been demonstrated by experimental testing in a constructed experimental set-up. Furthermore advantages and disadvantages with alternative system designs are investigated and discussed. Especially inclusion/exclusion of moisturiser is interesting.
A stationary thermodynamic model outlines the fuel cell system by modelling consumption, production and like in the DMFC stack along with distribution of heat loss and production etc. The results from the model are used for dimensioning of components. Aside from this, the model is verified using collected data from tests in the experimental set-up, which show good consistency in the
tested theatre of operations. This is partly due to model implementation of some of the data from tests with the aim to achieve an adequate model for dimensioning within a model on a limited scale.
In the experimental investigations, focus has mainly been on determining the amount of methanol emissions. These investigations has shown that the emissions released together with CO2 can be reduced from 8 to 2 vol-% methanol with 1 M methanol/water solution by reducing the temperature
of the flow from 70 ºC to 30 ºC. In the thermodynamic model of the power module this corresponds to a reduction in methanol emission from 7.5 wt-% to under 1 wt-% of supplied methanol. Apart from this, experiments have shown the potential for determining the methanol concentration
in the methanol solution using measurements of methanol emissions in the CO2-release.
Creation date: 2009-05-20
Update date: 2009-05-20