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Test Method and Equivalent Circuit Modeling of a PEM Fuel Cell in a Passive State

A novel test protocol is proposed for fuel cells that are in a nonfunctioning or passive state. Standard fuel-cell test methods are reviewed, along with the equivalent circuit models (ECMs) used to represent functioning or active fuel cells. Standard active tests focus on single cells, while the passive test is shown to be applicable to testing multiple cells. The passive test measures electrical characteristics of the fuel cell in the absence of electrochemical reactions. A simple ECM is developed to describe the cell behavior under the passive test conditions. Circuit model parameters of many series-connected cells can be acquired using the results of a single stack test. Proton exchange membrane fuel cells (PEMFCs) from three manufacturers were tested, ranging in system power from 12-500 W. Test results for each PEMFC exhibited similar behavior that is well predicted by the ECM. A strong similarity between a passive fuel cell and a double layer capacitor is discussed.

Delivering Sustainable Infrastructure that Supports the Urban Built Environment

Sustainable living will require megacity-level infrastructural support designs and paradigms.

Design and implementation of a community based sustainable development action research method

Local community groups have been forming around taking action on the issues of Peak Oil and Climate Change. People perceive a risk to their security and are alarmed by the lack of action at the government level. Sustainability of local communities, their infrastructure and social assets is a field that should gain as much attention from the engineering professions as green technology. This paper reports the development of the TransitionScape methodology and implementation in a weekend workshop in a rural town in New Zealand. The methodology was designed from first principles of action research and group psychology. The objective of the workshop was to transition the community from a point of fear and concern to a state of action by initiating community-generated projects that mitigate the risk of external un-sustainability. The workshop was a success, with numerous projects resulting from the one weekend. We recommend that Transition Engineering practitioners could deliver this workshop at a reasonable cost to communities around the world.