From: Dossy (dossy@panoptic.com)
Date: Tue Dec 11 2001 - 20:42:02 MST
Here's a simple explanation of what I was thinking about, at:
http://www.space.com/businesstechnology/technology/body_power_011128-1.html
Urine-based fuel cell: Yes, you can turn pee into power and not just
by turning a turbine after a few beers. First subject urea to
enzymatic hydrolysis to make carbon dioxide and ammonia, and then
oxidize the ammonia to nitrogen and water. But the center notes that
"one problem with the system is the need for alkaline conditions
that may require transport of sodium hydroxide, a hazardous
compound. Also, to achieve power generation in the range of 0.5 -
1W, a system to concentrate the breakdown products of urea, such as
reverse osmosis, will be necessary." But for astronauts and soldiers
on the run, "one attractive feature of this fuel cell concept is the
production of water as a by-product of the system."
I'm wondering if anyone knows of any working prototypes.
-- Dossy
On 2001.12.11, hal@finney.org <hal@finney.org> wrote:
> Dossy writes:
> > The question is, if I peed into my urine-powered clock before
> > I went to bed every night, would it provide enough power so that
> > it would keep good time when I woke up 8 hours later?
>
> Actually the liquid just supplies a conductive electrolyte and is
> not the source of the energy. A salt solution will work as well.
> See http://rabi.phys.virginia.edu/HTW/flashlights.html:
>
> How can you run a clock off of a potato?
>
> The classic technique is to insert two dissimilar metal strips into
> the potato in order to build a simple battery. You can then run an
> electronic clock with the power provided by that battery. But the
> energy in that battery is coming from chemical reactions of the metals
> and not really from the potato.
>
> Also http://www.newscientist.com/lastword/answers/349gadgets.jsp?tp=gadgets1:
>
> The energy powering the potato clock does not come from the potato,
> but simply from the electrochemical properties of two different metals
> being placed into a salt solution. As the questioner correctly notes,
> cola also works, as does any simple salt solution--try it with table
> salt. The potato acts as a compact, slow-to-dry, salt bridge.
>
> The metal electrodes are slowly dissolved (or at least one of them is)
> as part of the electrochemical reaction. The power comes from the fact
> that the different metals have different electrode potentials. It is
> not coming from the electrolyte.
>
> Hal
--
Dossy Shiobara mail: dossy@panoptic.com
Panoptic Computer Network web: http://www.panoptic.com/
"He realized the fastest way to change is to laugh at your own
folly -- then you can let go and quickly move on." (p. 70)
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