Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Step on the gas -- New fuel cell design adds control, reduces complexity

18.01.2007
When Princeton University engineers want to increase the power output of their new fuel cell, they just give it a little more gas – hydrogen gas, to be exact.

This simple control mechanism, which varies the flow of hydrogen fuel to control the power generated, was previously thought impossible and is a potentially major development in fuel cell technology.

The secret of their success is a system in which the fuel input itself changes the size of the reaction chamber, and therefore the amount of power produced. The breakthrough design also adds to the understanding of water management in fuel cells – one of the major obstacles to large-scale deployment of the technology in automobiles.

"It's almost so simple that it shouldn't work, but it does," said Jay Benziger, a Princeton professor of chemical engineering. Benziger developed the technique with Claire Woo, who graduated from Princeton in 2006 and is now pursuing a Ph.D. at the University of California, Berkeley. They will publish their findings in the February issue of the journal Chemical Engineering Science.

The first applications of their design are likely to be in small machines such as lawn mowers, the researchers said. The machines would be easy to use, incorporating a design similar to the familiar acceleration systems of cars that use a pedal to increase the flow of fuel and the power output. More important, Benziger said, the use of fuel cells in lawn care equipment would cut down on a major source of greenhouse gases, especially as emissions from these machines are not currently regulated.

At the most basic level, all fuel cells work by combining hydrogen with oxygen in a reaction that generates electricity, water and heat. In the Princeton system, some of the water produced as a by-product collects in a layer at the bottom of the reaction chamber, while the rest drains to an external tank. By varying the height of the water level in the chamber, Benziger and Woo are able to enlarge or shrink the reaction chamber.

For example, an increased flow of hydrogen into the chamber pushes more water out of the system, lowering the water level and increasing the space available for the reaction to take place. Similarly, a decreased flow of hydrogen causes the pressure inside the chamber to drop, drawing some of the water from the tank back into the system and shrinking the reaction chamber.

The water at the bottom of the chamber also serves to maintain the needed humidity for the fuel cell reaction to take place. This patented "auto-humidifying" design demonstrates an innovative use for the water produced during the reaction, which causes problems in most fuel cell designs.

Conventional fuel cells feature a complicated network of serpentine channels to combine the gases, maintain the appropriate humidity levels and eliminate water from the system. Often, droplets of water clog the narrow channels, leading to inefficient and irregular power production. The Princeton system mixes the gases via diffusion in a simple reaction chamber and relies on gravity to drain the water produced.

Benziger and Woo's reaction chamber is effectively sealed by the water at the bottom of the tank. By preventing fuel from leaving the system, this design ensures that the gases remain in the reaction chamber until they combine. Most traditional fuel cells repeatedly run hydrogen and oxygen through an open reaction chamber, converting only about 30 to 40 percent of the fuel at each pass. Since the Princeton system is closed, 100 percent of the fuel can be used with no need for a large and expensive fuel recycling system.

Hilary Parker | EurekAlert!
Further information:
http://www.princeton.edu

More articles from Power and Electrical Engineering:

nachricht How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt

nachricht Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP

All articles from Power and Electrical Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.

Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...

Im Focus: Climate satellite: Tracking methane with robust laser technology

Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.

Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...

Im Focus: How protons move through a fuel cell

Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.

As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...

Im Focus: A unique data centre for cosmological simulations

Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.

With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine

Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>