Cooln'it

[kickn]

Okay - My new 15v/40A PSU is being devliered this week. With upwards of 600W of cooling potential needed I'm thinking I have to start sorting the cooling situation.

Just wondering if anyone had any low-cost ideas for this?

I was thinking about anything from watercoolers to cheap fridges and thought that maybe a fridge - with silicon tubing running through it - might work okay. I know you have to watch the materials - is stainless okay? I'm assuming it would last the longest with the electrolite.

So - guru's - any thoughts?

[kickn]

After a couple of hours of conteplation I think i got it

In the same station I have water running through a reverse osmosis system for purification - much of this water (70%) is waste - if I also take this water and pass it through a heat exchanger then that should provide enough cooling to help things out - I'm sure I could make a heat exchanger (say with a stainless or aluminium core - any ideas?) fairly easily.

Any thoughts?

[sswee]

An old automotive heater core or trans oil coolers depending on size needed. Most are alum. now. Just an idea.

[M_D]

I think either of those ideas could work if implemented well enough.

Titanium is best for the heat exchanger, as aluminum and stainless steel will last a little while but get eaten up sooner or latter and spring leaks. I sure there are some variables, but .032" sheet aluminum about disappears after 4-5 months of contact in electrolyte. You wouldn't have much, if any, warning until the aluminum or stainless just literally fell apart. Under pressure with a pump, that could cause some problems.

A silicone or rubber material won't conduct the heat well, so it would not be the ultimate choice either, although with enough area it could help some.

There are small refrigeration units with titanium heat exchangers available; Caswell's had one listed. I don’t remember what the capacity is though.

One thing that helps is to have a larger tank, it takes longer to raise the temperature then. But if you use the full 40 amps at 15 volts, you could raise the temperature about 4-6 degrees an hour in a 60 gallon tank.

[kickn]

Unfortunately my tank right now isn't as big as that (being a very large plastic container) so I'm thinking that I'll have a problem on my hands.

Right now I'm doing 10A all day long and the temp isn't climbing more then a few deg. throughout the day. I'm planning on using abut 20 to 25A for a full set of parts.

A small heat exchanger would have to be the ticket I think. I was thinking of making on out of stainless and thought that 316 would last a bit longer then a few months. If its not going to then I'm not sure what the best option is.

My current thought was a larger stainless tube with copper tubing wrapped around it. Inside the stainless tube I would use a series of paddles or something to help aggitage the electrolite and make sure as much of it contacted the wall as possible. Again though if stainless isn't going to last then thats not much of an option.

Plastic is kinda out - unless I looked for a small chiller and ran the plastic tube through it - that might cause enough of a temp difference and suface area contact to work.

[sswee]

I found a CRC.pdf (chemical resistance chart) at Little Giant Pump site that is useful. It shows alum. & 316 stainless rated at C in sulfuric under 10%. A being excellent and D being not recommended.

[acidrain]

My settup:
40gal ano tank with a 10A power supply.
10gal cooling/heating tank sitting next to it, full of water.
~200gph plain ol' pond pump rated for salt water (plastic impeller, ceramic shaft) is placed inside the ano tank.
20ft of vinyl hose running from the pump in the ano tank, through a coil of hose sitting in the heating/cooling tank and back into the ano tank.
The heating/cooling tank is a metal tank with a valve at the bottom for easy draining. Built into this tank is a 3500 watt water heater element and thermostat. The thermostat is set at 90F.
Wired in-line with the ano circulating pump is another thermostat placed against the side of the ano tank. This is set at 68F.
This entire settup is built into an insulated plywood box with a closing insulated lid. This maintains my starting temperature nicely.
I usually don't have much temperature climb, but occationally I have to cool the tank, so...
I shut off the power to the heating element, drain off the heated water, and replace it with cold tap water.
I'm sure this type of settup could work for you too. Just substitute the heated water with chilled water.
I have had no ill effects with the vinyl hose, or pond pump ($15 on ebay)Hope that helps.

[kickn]

Funny you posted that acidrain!

I had just come to the conclusion that running pvc tubing into the bucket of water sits under the water outlet of water purifier would be the best option

I can get 30m of hose very cheap. I was thinking though - is it best to put spacers around the hose? To keep water on all sides or does it really matter?

I was just going to use a 'Y' valve or something to redirect the flow into the coil if the temp starts increasing. Later I'll automate this with a proper valve.

I've got a heater in the actual tank so thats not a problem there.

Thanks everying for replying to my silly posts! :P