Fuel Cell description from web site of Global Thermoelectric. There is a SI thread symbol GLE on TSE
The web site for the company is www.globalte.com
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A fuel cell is an electrochemical device that takes a fuel such as hydrogen and combines it with oxygen to produce electric power, heat and water. The fuel is not burned, but is chemically combined with the oxygen in the air. Since there is no combustion, the cell does not generate harmful emissions.
A fuel cell consists of three main parts. It has an anode, cathode and an electrolyte. The anode and the cathode are porous to allow the gases to pass through them. Between the two is an electrolyte, which allows the oxygen and hydrogen to combine, generating electricity and producing heat and water as byproducts. Figure 1 shows these main constituent elements.
There are several different types of fuel cells that are being investigated today. The proton exchange membrane ("PEM") cell operates at a low temperature (around 80 degrees C) and uses a specialized plastic membrane as an electrolyte. This type of cell requires pure hydrogen as fuel. The hydrogen may be supplied directly from tanks, or it may be produced from other indirect sources such as natural gas or propane by passing the fuel through an external device known as a reformer. Reformers are generally bulky and expensive. The PEM cell has very little tolerance for contaminants such as carbon monoxide or sulphur compounds.
Global Thermoelectric is developing a solid oxide fuel cell ("SOFC"). This type of cell operates at a temperature of more than 800 degrees C. The anode, cathode and electrolyte are made from ceramic materials to withstand the heat. The SOFC does not need an external reformer to make hydrogen. Instead, due to the high operating temperature, hydrogen is produced directly inside the cell using a catalytic process to break the fuel down.
When the cell is running, it produces a high quality heat as well as electricity. Using this heat outside of the cell stack allows the overall efficiency of the unit to be optimized. Applications such as heating residential water supplies and providing warmth for industrial buildings are among the options being studied.
In order to produce significant amounts of power, solid oxide fuel cell elements are assembled into a stack, analogous to a multi-layered sandwich. Cell membrane assemblies, each including an anode, electrolyte, and cathode are stacked with metal interconnecting plates between them. The metal plates, made of a special heat resistant alloy, are grooved to allow flow of the hydrogen and oxygen to the membranes. A ten cell stack is shown in the cutaway photograph to the right. The various horizontal layers of membranes and interconnect plates can be seen.
Solid oxide fuel cells will serve as the basis for power supply products to be developed by the Corporation. Global believes that the high efficiency and power output provided by this type of cell can be used in large potential markets such as telecommunication systems, oil & gas sites, residential & commercial utility applications as well as future hybrid electric vehicles.
Only a few organizations in the world have developed significant expertise in the design and construction of solid oxide fuel cells. Global has successfully negotiated an agreement with one of them. In the summer of 1997, the Corporation signed an Agreement with Forschungzentrum Jülich, one of Germany's largest research institutes, to transfer the technology and knowhow to Global. Their SOFC technology is among the most advanced in the world.
Global has also signed a contract with the Alberta Research Council ("ARC") of Edmonton to do initial investigation into the various options that might be practical for volume production of SOFC's. This directed research will focus on ceramic fabrication and evaluation techniques that are already being successfully used in other industries.
The first milestone in Global's fuel cell program was the assembly, testing and operating of a planar SOFC stack at the Corporation's fuel cell laboratory facility in Calgary. This objective was achieved on March 4, 1998. During the test process the planar solid oxide fuel cell stack produced electricity at a power level approaching ½ watt per square centimetre of membrane area, well exceeding expectations. The cell is shown here during operation within the furnace. To the best of Global's knowledge this is the first time that a planar solid oxide fuel cell stack has ever been assembled and operated in Canada. Although there is a considerable amount of work to be done to develop a commercially viable product, the Corporation is encouraged by the results thus far.
Early in calendar 1999, the Corporation hopes to have its first "made in Canada" prototype 1,000 watt planar SOFC stack ready for testing utilizing internal natural gas reforming as well as a complete Energy management System. In manufacturing this stack, the Corporation will use pre-production processes rather than the laboratory scale methods used for prior units. Achievement of this objective will demonstrate that commercially viable techniques can be applied to the volume manufacturing of SOFC stacks.
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