[extropy-chat] 'Cool' fuel cells

Mike Lorrey mlorrey at yahoo.com
Sun Aug 1 03:39:56 UTC 2004

--- Jeff Davis <jrd1415 at yahoo.com> wrote:> 
> Keeping in mind that one thin film SOFC is just a
> fraction of the size of a human hair with an output of
> 0.8 to 0.9 Volts, a stack of 100 to 120 of these fuel
> cells would generate about 100 volts. When connected
> to a homeowner's natural gas line, the stack would
> provide the needed electrical energy to run the
> household at an efficiency of approximately 65
> percent. This would be a twofold increase over power
> plants today, as they operate at 30 to 35 percent
> efficiency.

Wall voltage of 110/120 VAC is what is called RMS voltage, meaning the
120 volt rating is the root mean square value, or about 72% of peak
voltage (since it's a sine wave). Generating 120 volts DC is fine, but
you need to turn it into alternating current to do work with many home
appliances (AC is also more efficient, since it's just electrons moving
back and forth rather than taking a long trip). Power inverters can be
built which are 97% efficient or better.

> SOFCs, in general, operate at 900 to 1,000 degrees
> Celsius, a very high temperature that requires exotic
> structural materials and significant thermal
> insulation. However, the thin film solid oxide fuel
> cell has an operating temperature of 450 to 500
> degrees Celsius, one half that of current SOFCs. This
> lower temperature is largely a result of the
> drastically decreased thickness of the
> electrolyte-working region of these thin film SOFCs
> and negates the need for exotic structural materials
> and extensive insulation. The lower temperature also
> eliminates the need for catalysts (known as reformers)
> for the fuel cell. All of these features indicate a
> reduced cost for the thin film SOFC and positive
> future impact on the fuel cell market. 

Since fuel cells seem to be so good at producing heat, why don't people
use a liquid cooling system to extract more energy from the waste heat?
Cogeneration would up that already good efficiency even higher.

Mike Lorrey
Chairman, Free Town Land Development
"Necessity is the plea for every infringement of human freedom.
It is the argument of tyrants; it is the creed of slaves."
                                         -William Pitt (1759-1806) 
Blog: http://www.xanga.com/home.aspx?user=Sadomikeyism

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