Is OFC suitable for outdoor use? Can you demonstrate interesting fuel cell technology with live measurements at science fairs? YES, YOU CAN!
At the end of June 2024, we participated in the URBAN ZERO festival in Duisburg Ruhrort. As you can guess from the flyer, this show was an open event. Not only did the sun shine, but so did our test-proven OFC (Figure 1):
From left to right:
- Homemade electronic current load: This battery-powered load has been used for all previous OFC tests.
- DHE driver and voltmeter: This homemade standard current source powers the optional DHE reference electrode in the OFC MEA to determine the anode potential. An off-the-shelf voltmeter measures the anode potential based on a DHE reference electrode.
- OFC is equipped with optional DHE.
- Pressure regulator: The OFC hydrogen supply uses a HYDROSTICK. The pressure from the original outlet valve provided by the HORIZON fuel cell is reduced to about 100 mbar.
- Infrared camera: A small, low-budget IR camera measures the temperature of the open cathode of the OFC, which works with a smartphone (something everyone has today, to avoid extra costs).
- Power bank and USB hub: An external power bank powers the IR camera and smartphone, allowing temperature measurement for hours if the capacity of the power bank is sufficient.
As you can see, no external infrastructure is required to explore the world of fuel cells. And a fun environment (Figure 2) makes research even more fun, so let's get the science party going (Figure 3).
Figure 2: The entrance to Duisport – one of the sites of the URBAN Zero science festival
Figure 3: Burghard, one of the members of the OFC team, dismisses the OFC so that the scientific team can move.
It was the first time that the temperature of OFC cells was continuously monitored using an IR camera. The OFC gets very hot when drawing high currents, heating from 23°C (ambient temperature) to about 38°C (Figure 4 right). But why is there a cold spot on the flow field plate before balancing (Figure 4 left)? This is due to the warm light of the blue sky reflecting off the gold-plated flowing field plates. A piece of masking tape removed that reflection. Be careful with your IR camera to avoid misleading results by checking areas before measuring.
Typical electrical current working diagrams were reproduced during the exhibition. However, the wind has affected the performance of OFC in high current regime. While operating under a load of about 4 A, a sudden burst increased the cell voltage from about 100 mV to 300 mV. Therefore, to demonstrate the effect of forced convection on an open cathode to improve performance compared to natural conversion was not possible.
Nevertheless, it was proved that OFC is ready to produce good scientific results anywhere. And remember, a pleasant environment enhances the fun of research.
Below you can see IR-thermal images of OFC. On the left (yellow image) you see the OFC before the test exposed to the empty flow field. On the right (red picture) you see the OFC after drawing high frequencies for some time.