
The Fuel Cell For Home - jcr
http://www.fraunhofer.de/en/press/research-news/2014/june/the-fuel-cell-for-home.html
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jcr
The following links in the submitted article as text, but are not given as
clickable links. They give more details about the field testing being done.

[http://www.callux.net/home.English.html](http://www.callux.net/home.English.html)

[http://enefield.eu/](http://enefield.eu/)

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marvin
Does anyone know what makes this more compelling than static power generation
over the electric grid? Gas-fired power plants are pretty efficient. Is this
significantly better?

~~~
maxerickson
The big win is having the waste heat available at the house.

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otterley
What if you live in a warm climate?

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brc
People in warm climates still have hot showers and need to dry their clothes
on rainy days or at night. Or maybe they want to heat up their pool to use all
year round. There's always a use for waste heat.

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Zigurd
The article seems to claim direct conversion from methane. That sounds
unlikely. If they are not direct methane fuel cells, how do these systems
create hydrogen?

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EEGuy
Zigurd, I doubt the "direct" 'gas to electricity' claim in this press release.

Near the bottom the press release admits the conversion /isn't/ actually
"direct", stating:

    
    
      If the fuel cell heater is connected to the gas network, 
      a reformer initially converts the natural gas into a 
      hydrogen-rich gas.
    

Ah-ha: A "reformer": That would be a 'steam reformer[1]'. Quoting [1], here's
what a 'steam reformer' does:

    
    
      At high temperatures (700 – 1100 °C) and in the presence
      of a metal-based catalyst (nickel), steam reacts with 
      methane to yield carbon monoxide and hydrogen. These two 
      reactions are reversible in nature.
    
        CH4 + H2O ⇌ CO + 3 H2
    

So there it is, the 'hydrogen-rich gas' is syngas [3], one mole carbon
monoxide plus 3 moles hydrogen.

The syngas can either be burned directly (producing CO2 and heat of course),
or continuing per [1], separated from the H2, then combined with more water:

    
    
      Additional hydrogen can be recovered by a lower-
      temperature gas-shift reaction with the carbon monoxide 
      produced. The reaction is summarized by:
    
        CO + H2O ⇌ CO2 + H2
    

But the article uses just one word, 'afterburner' which tells me they're
burning away the carbon monoxide:

    
    
      The researchers were particularly responsible for the 
      construction of the prototype, the design of the overall 
      system, the design of the ceramic components and the 
      development of the reformer and the afterburner.
    

Not clear is whether the CO goes /through/ the ceramic SOFC or is separated so
it can /bypass/ the SOFC then get remixed with some H2 at the 'afterburner'.
No mention of a 'separator', so perhaps the CO does go straight through the
SOFC along with the H2 without ruining the SOFC.

In any case, we see this CHP plant with its SOFC requires water in, makes
carbon monoxide in the process, which it 'afterburn[s]', certainly putting out
CO2 [the Carbon from the methane can't just disappear, would you have that as
carbon monoxide or carbon dioxide?], and needs some heat to run the steam
reformer. There goes some of your thermal efficiency!

[2] has a bit more on home CHP.

So long story short, there's no free lunch here:

* It can't hit 100% thermal efficiency

* It releases CO2

* Its intermediate stage passes H2 through, and CO either through or around the SOFC, then burns off the CO to CO2

* It needs water as well as natural gas to work

Presuming the Bloom Boxes also use SOFCs and methane, the operating chemistry
would be the similar at the inputs and outputs: Natural Gas and Water in;
Heat, CO2 and Electricity out.

There may be an advance in materials science if the SOFC accepts syngas ( CO +
3 H2 ) directly without bypass of the CO and without cell degradation from the
CO, but the press release says nothing specific about, or suggestive of that.

edits for dialog form, clarity, corrections, 'afterburner' clean up the CO in
the syngas to CO2, no water out, oh it says press release right at the top, no
wonder it reads like one

========

[1]
[https://en.wikipedia.org/wiki/Steam_reforming](https://en.wikipedia.org/wiki/Steam_reforming)

[2]
[https://en.wikipedia.org/wiki/Home_fuel_cell](https://en.wikipedia.org/wiki/Home_fuel_cell)

[3]
[https://en.wikipedia.org/wiki/Syngas](https://en.wikipedia.org/wiki/Syngas)

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thedays
How is this fuel cell different to some of the other products out there? e.g.
[http://bluegen.info/](http://bluegen.info/)
[http://www.flowenergy.uk.com/the-flow-boiler/meet-
flow](http://www.flowenergy.uk.com/the-flow-boiler/meet-flow)

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gnoway
This is a solid oxide fuel cell, right? What makes this one better than the
bloom energy devices?

Speaking of which, what happened to the bloom boxes? Are the big customers
still customers?

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jmelloy
I've been keeping a casual eye on them -- they seem to be selling to big
customers, but at $750k apiece. They're also the size of a bike shed, and
generate 100 kW.

This is the size of a stack of CDs, and generates 1 kW. (Which is enough for
lights, tv, etc, but generally not the stove.)

