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DIY Peltier "ICA" Chiller


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Have you tried a computer power supply yet? I know of a place locally that has 12V power supplies. Actually, they have a little of everything electronic. I might pay you for a copy of your acrylic pieces so I can try my own.

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Perpetual98

I haven't tried a computer supply yet. I'll go upstairs to our "dead PC" room and see what I can pillage.

 

 

Ok, pillaged a power supply. Now I need to remember which wires to jumper to turn it on. Here's what it says, so you guys can tell me what you think makes the most sense:

 

AC Input: 115V / 5A

DC Output: 5V / 18A, 12V / 3A

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green and grey turn it on. I'm 99% positive. I can check for you though if you're not sure (I have a power supply in my closet).

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Perpetual98

Thanks halfpint. This is a goofy Dell power supply and it doesn't even have a green on it. (I thought it was either green or blue that turn it on)

 

It ended up being grey and black on this one.

 

FWIW, the 12V on the PC power supply seems to work better than the 5V leads.

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I just thought of another idea. Why not get a car battery charger and use it! It can pump 12 volts at as much as 20 amps! That would definately chill your peltier.

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let me shed a little light here before you make the same mistake that I did, I built this stupid thing last month.

 

I used a 250W 50mm peltier from ebay. For heat sink, I use a aluminum/copper with 4 heat pipes in it. Design wise, check out the picture below.

 

Power supply is the biggest problem here. I have a lot of computer power supply lying around so I guess tried them out won't hurt, without doing any calculations at first, BIG mistake. first I used a 150W, 8A@12V, big spark and smells right after I turn it on. ouch, but no problem, couple more PS to go. Second I used a 200W micro ATX, 10A@12V, turned on fine, everything seems fine....not. When I tried to move the wire around, they are soooo hot that it seems like they are starting to melt, turned it off right away. So third and last, I used a 250W 10A@12V, everything runs fine, nothing melting, nothing smelling, all good, but when I check the voltage drop across the line, it was only left with 8.96V. So this lesson teaches you, find a good power supply for your peltier, do the math first before you plug it in, it draws current like there's no tomorrow. I am both ME and EE, I should have known better, that's different story.

 

back to my testing data, I use a 5G bucket. 3G of water in it, used a 60gph pump to pump water into the little device. room temp at 77-78F, water temp started at 83F, no heating load to the water when experiment starts. the device dropped 1F every 15min almost linearly. as the temp gets lower, for each 1F drop, it took nothing more then 20min, temp stopped at around 69F. when I woke up the next morning, the temp is at 68F, as I mentioned above, room temp is around 77-78F, so that's around 8-9F drop below the ambient temp without any heating load in the water. waltage is around 90W. the heat sink is very good for doing it's job, because of the heat pipe design, totally recommand it.

 

below are couple pics, the device is 3.5"W x 4"L x 0.75"H, any more questions, please let me know. Enjoy!

post-4199-1152860689_thumb.jpgpost-4199-1152860707_thumb.jpgpost-4199-1152860717_thumb.jpg

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Long time lurker here at Nano Reef, but I felt it was time to finally register so I could share my story with everyone.

 

Perpetual, I tried doing something very similar to your design and used a computer power supply. I had some TECs that I bought from ebay, figuring that they woudl be cheap and all. The ebay auction I won them from said that they were the most powerful TECs available, so I picked up 2 of them.

 

I hooked up my power supply and it seemed to work pretty well. I set it up and started to test it in the water. It was doing a great job of cooling my tank. I was happy and very proud of myself, being a dIyer.

 

I came home a few hours later, and smelled a burning smell. My computer power supply was burning and a small FIRE!!! It caught the bench I was testing it on fire and also some power tools and even burned all the way to the wall outlet. The fire inspector said that the fire started in my power supply. Luckily I doused it with a fire extinguisher.

 

I dont know what happened, but I know that I was stupid for trying to save money by DIY'ing this project.

 

I am no engineer, but I thought I could save some money by trying this DIY. I regret ever trying this mod, and hope someone can learn from my mistakes.

 

In this hobby, its not good to be cheap. I am lucky i was there in time to put out the fire, before my entire garage caught fire. My wife didnt talk to me for a few hours and called me some names that I cannot repeat in public.

 

She threatened to take away my reef.

 

So the moral of teh story to everyone. BE CAREFUL. Saving a few dollars is not worth risking your life and limb over.

 

Even worst is that my insurance (state farm) wont cover the damage. It looks like i may be out a few thousand dollars (for the electrical damage to my wall and other burn damage)

 

Let this be a lesson to everyone. If you want to try this, make sure you know what you are doing.

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Perpetual98

Good info guys! Thanks! So what I've gathered is that a PC power supply might not be the best idea, or perhaps with a controller it would be ok because it wouldn't be running all the time. I'll do all of my "testing" at work so I have several hours to observe it.

 

Regardless, I'll probably use the Sola/Hevi-Duty SDP-2-12-100T power supply that I played with yesterday. I think it offers some overload protection. Here's the page on the SDP line:

 

http://www.solaheviduty.com/products/powersupplies/sdp.htm

 

diy_man, I've had my wife not talk to me for days before, so a few hours from your wife wasn't too bad. :)

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The power supplies cought on fire because they were not rated at high enough amps. The Peltier will pull as many amps as it needs which are a lot. If the power supply is only rated at 10 amps and the Peltier is pulling 15 amps the power supply will over heat and catch on fire. The way to keep this from happening is by building a inexpensive current regulator. The circuit consists of a LM317 a few capacators and a Potometer and resistor. Here is a link to one Current regulator

 

This will limit the amount of volts and amps the peltier can pull. Thus you can use any power supply you want. The more amps the better though if you want any kind of cooling from the Peltier.

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Perpetual98

Here's the deal with electronics. You can show me schematics all day and it might as well be in Sandscrit. I'd be more than willing to build up a current regulator if someone showed me what parts to buy and how to hook it up. Heck, even a highly technical MSPaint drawing would help. :)

 

Eric

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Once I finally find a LM317 I will build the regulator and take pictures. I don't want to order only one due to shipping costs. The LM317 only cost about $3.00 but shipping is like $8.00. All the capactors and resistors and pot. I can find at radio shack.

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Perpetual98

Go to national.com and see if you can get free samples. I do that all the time when I want to tinker. Let me know what the part number is that you find and I'll order some up too.

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Here is what I ordered today. LM338 I ended up getting an LM338 instead of LM317 due to Amp limitations of the lm317. The LM317 only supported up to 1.5amps and the LM338 suported up to 5 AMPS which is about what I want to supply and is all my powersupply will provide anyways. I ordered 5 of them for $16.00 S/H using the free samples link. Very cool thanks Perpetual98. I should receive them middle of next week and I will start experimentations.

 

Brad

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I don't remember if it was mentioned here or in another thread, but you can find self-regulating power supplies that automatically limit the # of amps that they will produce. Note though that it was also mentioned that you need a current limiting, not a current protected transformer/power supply. The self protecting ones apparently shut themselves off at the current ratting, and that would be useless.

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I'll throw in my experience w/ TEC chillers. I have an ICA Chiller on my 24g DX Cube. I am using an old PC power supply to power it and have been for almost a year.

 

Cooling the "Hot" side is VERY important. So is "warming" the cool side (water flow). I have a fan speed control on the fan for the "Hot" side. If I have it running full speed the wires for the TEC stay cool. If I turn the fan speed down the wires will get VERY hot. So without measuring the amperage draw I would say that the "hotter" the hot side gets the more amps the TEC will draw. Keeping the "Hot" side as cool as possible increases the cooling on the "Cool" side but also reduces the current draw of the TEC. If you are relying on nothing more than a heatsink for keeping the "Hot" side cool you're asking for trouble.

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Perpetual98

I just got my ThermalTake heatsinks in yesterday, and I'm hoping that they're better than the one I have now. I also need to find my P4 heatsink. I don't think I would have tossed it.

 

FWIW, I ran the TEC for about 9 hours yesterday at work and the Sola power supply barely got warmer than room temperature. I have one of those mini-fridges that has a TEC in it and that has a 12V 4A power supply and that thing gets HOT when I run the mini fridge. Part of me wants to rip that fridge apart, but I do use it occasionally.

 

I also ordered another TEC yesterday that looks a little beefier than my current one. I'm STILL working on figuring out the controller. I just don't want to break down and order a Ranco. :)

 

Eric

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Ummm... i think I found a little problem with your regulator. The max current output from that device, according to national is 1500mA. For a device that wants to run at like 4+ amps, the cooling effect will be almost nothing! While I was trying my little theroy (below) I ran .03A through the peltier and I couldn't even feel a diference on the cold side. Unregulated it was pulling like 4.8A and getting dang cold real quick. I could be wrong however, ans I have not seen the schematics for your regulation circuit. Here's what I came up with:

 

(copied from the other DIY chiller thread)

 

True enough, a power supply like that is going to be $$$. On the other hand though if you can find one putting out like 13.5 volts, with a self limmiting amp output at like 5-6 amps, then that shouldn't be too much. You just have to be carefull though, because if it's not self limmiting, then the unit will try and draw full amprage (say 8-9 amps) out of your 2.5a wall wort that you stole from your answering machine. The result of that will be a VERY hot transformer/cord, and posibly a fire.

 

Your other option is to build a current limiting circuit to go inline between a cheap power supply (ATX computer supply) and your load (cooler/fan). I'm still workin on that one...

 

alright, correct me if i'm wrong, but couldn't the current limiter be nothing more than a large resistor? Say you have a power supply rated for 12vdc at 5a. Hooking the chiller directly to this would result in a massive amprage draw. However, if you were to place a resistor inline with the chiller, the amount of current alowed to flow could be limited. In this case we have 12v, and our ideal current draw is 4.8a. Using Ohms law, (R=V/I) R=12vdc/4.8a, so R=2.5ohms.

 

Gheto diagram:

chillerlimiter.jpg

The fan is going to draw like .12amps, so that would leave 4.68a for the chiller module. That should be more than enough to cool things down, you only need one power supply, and the power supply never sees more than 4.8a, which is below its 5a rating. This is all just theroy at this point though, and seeing as to how it's 1:45am this could be a very messed up theroy.

 

I tried the above with a 12v supply rated at one amp and used the only resistor I had around which happened to be a 360ohm 1/4watt. Sure enough I was reading .03a through the circuit. (I=V/R I=12v/360ohm, so I=.0333) The only problem I discovered is that the little resistor did heat up a lot!!! I think it's because it's only a 1/4w. If I got one rated for mabey 3/4w or 1w, then it wouldn't be so bad... I can't remember if that's right though... I may have to correct that in the morning when I'm thinking straight.

 

 

Well, enough for now, I need to get some sleep, and I still haven't fugured out the important part where we get the cold part in safe contact with the water...

Edited by Xytrix01
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ok, i searched a bit more, and it looks like a LM338 would be a better choice for this app as it can supply 5A constant and 7A peak.

 

http://www.national.com/pf/LM/LM338.html

 

EDIT:

 

Nevermind, I somehow missed this post entierly... :huh:

 

Here is what I ordered today. LM338 I ended up getting an LM338 instead of LM317 due to Amp limitations of the lm317. The LM317 only supported up to 1.5amps and the LM338 suported up to 5 AMPS which is about what I want to supply and is all my powersupply will provide anyways. I ordered 5 of them for $16.00 S/H using the free samples link. Very cool thanks Perpetual98. I should receive them middle of next week and I will start experimentations.

 

Brad

Edited by Xytrix01
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  • 2 weeks later...
Perpetual98

Ok kids. I got a different peltier off of ebay. The original ones that I had looked wimpy and compared to the new Melcor (I think that's the one) that I got, it was wimpy. I've made ice with the new one with the same power supply. I'm going to run it for a while and see how warm the power supply gets. The new peltier just cooks the two other heatsinks that I was using before. They get too hot to touch. I used a P4 heatsink/fan that I had laying around at home, but unfortunately, that doesn't fit onto the acrylic block that I built. I'm waiting for some drills and taps to come in today so I can tap a couple of NPT holes into the block so that I can screw some fittings into it.

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Perpetual98

Ok, here's some teaser pictures. I need to get some fittings today at lunch so I can plumb it up and see if the darn thing works. I put the smaller heatsink onto it because that's what I designed it for. I have a 10G tank in my office at work and I'll see what, if any, temperature reduction I get. My office is rather warm. At this moment, the tank is 79.5 and my office is 81. Yikes, I need A/C in here.

 

Ignore my crappy acrylic job. It's just a prototype, I'd do different stuff next time. Sandwiching acrylic with Weld-On 16 creates lots of bubbles, but it should work. I'll be using a Mini-Jet 404 to pump the water...

post-6074-1153930378_thumb.jpg

post-6074-1153930387_thumb.jpg

post-6074-1153930394_thumb.jpg

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Perpetual98

Ok so far, not so good. I can't get it to stop leaking. I had an acrylic accident this morning when I was tapping one of the holes. Didn't think it was that big of a deal, but I guess it was. I guess I'll have to find another waterblock or come up with something else.

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Perpetual98

Well, before I stuck any more time and money into this thing, I decided to rig this leaky one so that I can see if it actually does anything on the 10G tank. I have it propped over the tank so that any leaky water just goes back into the tank. Room temp 81, water temp 80.1. I'll give it a couple hours before I go home to see what it does.

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