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Megaflow battery arbitrage

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BigBad

Mon Apr 28 2014, 04:34PM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600

I've been looking at the Harvard flow battery:

The parameters of interest are the cost of the storage chemicals being about $27 per kWh of capacity and the apparent longevity, they ran it 100 cycles with no loss of capacity or obvious changes; and they were getting about 99% electrochemical efficiency.

Thing is, although they didn't test it that long, projecting it to a life of (say) 1000 cycles, that's about $0.027/kWh, whereas the difference in economy 7 night rate in the UK to the normal rate is about 7p.

So potentially you don't even need any solar panels, just charge the battery up at night and run your house off it during the day.

Theoretically, if you have an old-style meter you could increase the capacity and run your meter backwards during the day, making a net profit! (I don't think the regulations work quite like that though in the UK, but there are similarish CHP provisions).

It looks like the information necessary to do this is in the paper.

It seems potentially to pay for itself remarkably quickly.

It would be fiddly to do though, there's only been one research scale cell built so far.

Sulaiman

Mon Apr 28 2014, 06:27PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

I do not fancy Bromine dissolved in Hydrogen Bromide anywhere near any living thing
I can't see how it could ever be called 'Green'

BigBad

Mon Apr 28 2014, 08:06PM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600

Reading the wikipedia page didn't fill me with horror.

Just how toxic are we talking; like chemical weapon toxic? It's supposed to be less toxic than chlorine.

Sulaiman

Mon Apr 28 2014, 11:13PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

e.g.

,d.d2k

Bromine appears on Wikipedia "List of highly toxic gases"

with a short term exposure limit of 0.2 ppm

Bromine is also used as an insecticide
and is toxic in run-off water to aquatic life

Definitely NOT a 'Green' substance

BigBad

Mon Apr 28 2014, 11:36PM

Registered Member #2529 Joined: Thu Dec 10 2009, 02:43AM
Location:
Posts: 600

Green compared to what? Fukushima?

0.1 ppm is quite low, but that's a 15 minutes limit.

It's not like chlorine CDC:

that stuff will mess up your lungs, eyes, everything.

Here's the CDC on bromine:

It seems to be more of an issue if you drink it; it's closer to iodine.

edit: oh wait hydrobromic acid indeed sounds pretty nasty

2Spoons

Tue Apr 29 2014, 03:10AM

Registered Member #2939 Joined: Fri Jun 25 2010, 04:25AM
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Posts: 615

There seem to be a number of redox battery chemistries - I quite liked the vanadium one, as it used vanadium in sulphuric acid on both sides of the membrane (II-III redox on one side and IV-V on the other side), which means cross-contamination by diffusion is not a problem.

Patrick

Tue Apr 29 2014, 05:45AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Use it on the battlefield, then when your done, throw it at the enemy. It's their problem then.

Sulaiman

Tue Apr 29 2014, 05:23PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

" Use it on the battlefield, then when your done, throw it at the enemy. It's their problem then. "

Is this the same Patrick that wants finance for 'environmental research' helicopters ?

Patrick

Tue Apr 29 2014, 05:46PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

i was being facetious....
it surprises me so little has been said on the recent use of chlorine to commit murder in Syria by Asad.
The media (definitely in America, apparently elsewhere too. ) seem to treat this as no big deal.

or do those of you in other nations see it in your media?

in any case H + Br compounds sound like a legal disaster waiting to happen, since lawyers hover like vultures of LiPo battery fires as it is now. And dont get methanol near it, if the device breaks open. but maybe theyll find another quinone pair, that works well without being poisonous.

EDIT: its interesting that they got around the need for precious metals, thats a problem with PEM fuel cells too.

Sulaiman

Tue Apr 29 2014, 06:31PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

AFAIK the bomb(s) were 'barrel bombs',
explosive but not toxic.
(watch a little Al-Jezeera, RT, CCTV etc. as well as your local propaganda)

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