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Refrigeration for electrolytic cells?

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LAN_403

Polar

Sat Apr 21 2007, 04:36AM

Registered Member #660 Joined: Fri Apr 20 2007, 07:36PM
Location:
Posts: 8

Hello folks, i'm a new member to the board. One thing that i am very interested in is a fairly efficient refrigeration system in the range of -10 to zero deg. C. I doubt such units exsist for a decent price, and even if they did, i doubt they would be optimized for my purpose.

Things that would be nice would be a hydrogen and oxygen outlet (they will essentially be combined, which sounds risky, but there should be only a few mL of mixture if the ID of the removal hose is small enough), as well as wire inputs. I have used salt water ice baths, but they tend to warm up too quickly. the ideal would be an salt water ice bath with Magnesium Chloride inside of the refrigeration unit, with the cell inside.

I have no expierence in refrigeration. I'm wondering if i should make or buy a unit, approximate costs of both, and what working fluid and parts to use if i do decide to make one.

Also, for the hydrogen/oxy tube, i can not decide if some palladium black would be good for a combustion catalyst. it would probably splash some of the electrolyte from my cell into the Magnesium Chloride bath, but after that, it should burn at the rate it is produced.

Any ideas, comments or saftey precautions would help a bunch also!

Thank you!

Sulaiman

Sat Apr 21 2007, 07:02AM

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

If you're not a refrigeration expert
then I guess the best option would be a commercial refrigerator/freezer.

Check with family/friends if anyone is about to buy a new freezer/fridge
and offer to get rid of the old one

Polar

Sat Apr 21 2007, 07:25AM

Registered Member #660 Joined: Fri Apr 20 2007, 07:36PM
Location:
Posts: 8

I guess i did not accurately describe what i meant- my cell is only about 1/4 of a liter. i would like a small refrigeration unit to save some power, instead of running a vary large unit for a tiny cell :)

Speaking of family and friends, my dad used to work on refrigerators a while back. His sense of smelling has been weakened by the sulfur dioxide they used back than. He may be able to help- but i'm not sure exactly how much work he did on them.

Steve Conner

Sat Apr 21 2007, 09:43AM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

You might be able to get some cheap Peltier coolers off eBay.

Polar

Sat Apr 21 2007, 11:07AM

Registered Member #660 Joined: Fri Apr 20 2007, 07:36PM
Location:
Posts: 8

Great idea! I always thought these were expensive, and that is the reason i had never bought one. If i could get a square metal box, i could probably get 10 of these units, that would leave me with 5 for all of the sides of the box, and five more to regenerate some of the energy used to create the heat. It does not have to be that large, and i believe that it should get cool enough! That is about 456 watts, which is quite a bit of juice. My PSU can only handle 1000 watts, but i use that for electrolysis, because it is current and voltage regulated.

For "cool" part of the regenerative side, i'm not sure which type of heat sink to use. I could use an air one, or maybe heat pipes? I'm not sure what the reverse efficiency is, but it does not look that great. It sounds like a lot of extra trouble, but if it could save me a bit on my electric bill, that would be nice!

The only thing this would require me to do is change the size of my cell, which would not be hard to do, and may actually help quite a bit. My other cell was too large- my anode was a piece of platinum wire, cathode is 1 foot of 10 gauge silver wire, and the platinum fits inside of the coil. I burned the platinum wire in half because the first cell was too big.

It is pretty early right now, but i'll draw up something that shows what i'm thinking about. I'm probably not making much sense right now :(

Bjørn

Sat Apr 21 2007, 11:42AM

Registered Member #27 Joined: Fri Feb 03 2006, 02:20AM
Location: Hyperborea
Posts: 2058

If I understood your design correctly you can't use any temperature differneces to generate electricity without a huge drop in efficiency so you will always be at a loss if you try. You need to draw a diagram so we can see exactly what you are thinking.

You also need to calculate the heat transfer before you buy the peltiers, adding peltiers randomly may even be worse than a passive heatsink. For the peltiers to work properly you need a very efficient heatsink on the hot side. The colder the hots side is, the higher the efficiency.

DrZoidberg

Sat Apr 21 2007, 04:23PM

Registered Member #350 Joined: Mon Mar 27 2006, 05:14PM
Location:
Posts: 106

peltier elements are inefficient. It's better to use a normal refrigerator and maybe add some more heat insulation e.g. styrofoam.

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