# Peltier Cooler



## Rain_Frog (Apr 27, 2004)

Some of you DIY folks recommend using epoxy to bond to acrylic. How strong is it really? Has anybody actually used it to stick to acrylic? (basically, some first hand accounts). Will it be strong enough if you "yank" it off? I've sanded acrylic a ton before, and silicon will still peal right off with your own hand strength.

I've only had experience sticking epoxy to epoxy (when making coats for backgrounds).

I'm planning on cutting a square in acylic and patching it with a square of titanium sheet metal, in which a peltier can attach to the other side. All I need is a leak or a seal failure and then I cause a fire or electrocute the frogs. :shock:


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## defaced (May 23, 2005)

I'm pretty sure all silicone sealants won't stick to certian polymers. My DAP Aquarium Silicone says it won't stick to methylmethacrylate, polycarbonate, polypropylene, polyethylene and polytetrafluoroethylene. I'm almost postitive acrylic is a polycarbonate. 

What about a mechanical link, say like some stainless hardware to hold the ti to the acrylic? Does the peliter work on DC? If you have a drawing of your idea I might be able to help more.



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## Rain_Frog (Apr 27, 2004)

You know, I was thinking about the "sump box" being made of stainless steel, but cutting through metal I have no knowledge of. I don't know if I can get a large enough sump box out of grade 321 stainless, the kind used for beverages. Obviously, the only advantage of using a stainless steel sump is because you can easily bond epoxy or silicone to it. However, I would have to insulate it with styrofoam. 

Another possibility, but less efficient, is creating a heat exchanger box or water bucket. My other, compressor chiller has a water tank where the cooling coils sit in and a titanium heat exchanger comes into contact with it. I did this because aluminum would corrode coming in contact with acidic water. Another idea is to make a "fridge box" around the cold coils to keep things cool.

Possibly, I could hook up a "fridge box" (beer cooler peltier idea) to a peltier so I wouldn't need to worry about bonding epoxy/ silicone to acrylic, but it isn't as efficient. However, at least I could take advantage of the cheaper Ti tubing (not to say that's much cheaper either).

Problem, if water flows out through the sump, through a titanium heat exchanger in the fridge box, how would it reenter the vivarium? I have no problem with the big chiller, as a temp controller powers my Rio pump whenever the water needs to circulate through the water sump, and back to the tank.

Still, epoxy is a great way to go, but its so expensive and taking the time to dry it and cutting wood for a homemade sump is time consuming. It took me several weeks to finish my DIY epoxy background.

Anybody used the Tough as Tile or the bathtub paint (by Liquid nails)? Its a two part epoxy paint that sells for $25 for coating your bathtub.


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## defaced (May 23, 2005)

Right now the image isn't showing, I'm not sure if that will change later. If it's still broken I'll fix it. Anyway, what I'm picturing is an insolated box with a small heat conductive area to which a peliter will be attached for the purpose of cooling water. Is that correct? Where will this water eventually go?

If that is the case, I can see some problems from a theoretical standpoint. A peliter does a great job of cooling, infact too great for use with water. At standard conditions your peliter will quickly turn your chill box into an ice box if you don't have a large enough flow. If for some reason water flow stops, and your peliter keeps working you could end up with a busted chill box because of the water-ice transisiton. 

As you said, SS is a bit of a pain to work with and it's a conductor so you won't be cooling your water as much as you could. Have you considered Gorilla Glue, with the addition of some SS hardware at the corners of your TI plate? Perhaps a plywood box coated in polyuretane wood finish.



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## Rain_Frog (Apr 27, 2004)

> If that is the case, I can see some problems from a theoretical standpoint. A peliter does a great job of cooling, infact too great for use with water. At standard conditions your peliter will quickly turn your chill box into an ice box if you don't have a large enough flow. If for some reason water flow stops, and your peliter keeps working you could end up with a busted chill box because of the water-ice transisiton.


Yes, that is a problem...if you don't have two temp controllers. My other chiller has two temp controllers, one cheap one for beer, and one fish type kind to monitor the tank temp (on the big tank). However, I haven't incorporated the "chill box" yet, instead, I used a rubbermaid container filled with water with the cold coils submersed. Probably though, it is more stable and less strain on the dehumidifier than a chill box surrounding it. However, that a chill box would be certainly less messy than a big tank full of water and probably better for the cooling coils.

I think one problem with this design, unlike my freon based chiller, peltier's hot side will most likely traverse to the cold side, so a standard temp controller will not work (you would cause the device to stop, then start up again, thus having to recool itself after some heat migrates to the chill box). A special temp controller for peltiers is needed (like the one for the iceprobe).

Probably the best idea is to make a carbon copy of an iceprobe. I have drawn out plans to make one, but when I have calculated the cost for all the individual parts, it turns out to be no more expensive than the real thing, and STILL no temp control included in the price. Instead, you would slip a piece of Ti tubing through a bulkhead and seal up the gap between the Ti tubing and bulkhead inside. Inside the titanium tubing itself, could be an aluminum rod that connects to a small aluminum block, attached to the peltier itself. 



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## defaced (May 23, 2005)

I've got a few ideas, but I'll need the basics to run the math. 

Ok, so what are your design paramaters? 

How much water do you need to cool and by how much? 

For what purpose is this water being cooled? 

Where is your ideal location for the chilling device? 

What materials/tools do you have available?



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## Rain_Frog (Apr 27, 2004)

Ok, so what are your design paramaters? 

*snip: How much water do you need to cool and by how much? 
For what purpose is this water being cooled? *

I'm going to start with the firebellied toads. I'm only needing to cool a couple of gallons for my 10 gallon tank, for starters. They are most important to keep cool. They tend to darken and become more nocturnal when temps reach above 75, not easy to maintain in my room. I don't want another frog tank in my crummy, dirty basement.

*snip: What materials/tools do you have available?*
If I find a place for cheap epoxy, and an easy way to cut wood, all I need is a titanium plate, a powerhead, and a peltier/ heatsink/ temp control combo. A cheap acrylic box is what I had in mind, if I put screws in to tighten it (using silicone like an O ring) but the drawback is that acrylic warps. I'm afraid that if it warps, then I'll spring a leak and start a fire or electrocute the frogs... that's why an epoxy box i think is safer because you can bond epoxy or silicone to the metal, that way. There is another option, using an actual glass tank. Perhaps a glass place can drill a hole that large for the peltier plate? (about 3-4") That'd be a good idea.

*Where is your ideal location for the chilling device? *
Two scenarios. The ideal scenario, is a sump. Ten gallons aren't easy to drill, or at least drilling glass. Plus, then I need to remove another frog tank because the bottom shelf must be used for a sump. My mantellas are on the bottom shelf, and a sump underneath, but often the water splashes on the iron stand and for sometime (thank goodness I caught it in time!) rust and paint was getting into the sump water. A sump that narrow in height isn't recommended either for mounting peltier devices.

Then, there's the hang on box idea. My powerhead/ filter should be on all the time, unless it breaks. I guess you might be a little concerned if the powerhead fails, and the chill box overcools, it could burst, but at least I wouldn't need to worry about drilling a 10 gallon (However, the microchiller has a peltier inside of it) A sump is safer.

Perhaps I should hook up a cheap reptile temp controller inside the hang on box, just as a safeguard if the pump fails? (so it will override the other temp controller that monitors the water temp)

Another idea, is to drill directly a large hole into the tank, but not sure if you can do that cheaply. But then there is no need for epoxy/ acrylic, etc. Just be careful that the cold plate is always submerged and sectioned off (perhaps behind some rocks) so the frogs will not come into contact with it. It is probably the most efficient, and is like how the iceprobe itself works.
If this was used for dart frogs/ mantellas, perhaps allowing wet soil to come in contact with the cold plate would be sufficient, like heating cables are for growing seedlings. (perhaps a titanium tube should be placed under the soil as well to spread it out).

At this rate though, it seems that its best just to go searching on Nanoreef.com and ask if anybody has used Iceprobes. You can get some good deals for them and the temp controller.

It either that, or I ask my local glass shop if they can actually drill into my tank (or a glass tank sump) a 3" hole. How much would that cost? I have an old 5 gallon that I hate that I should get rid of anyway some how. Perfect for a sump.

Doug


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## defaced (May 23, 2005)

I'm really thinking either a completely different approach is going to be needed, or a iceprove is going to be it. Without drilling the tank I really can't think of a way to get this to work easily, unless the pump you plan on using is going to be inline, not an inexpensive submersible one. I've thought of replacing the bottom the tank with metal and putting the peltier uner the whole thing, replacing the back with acrylic to make it easier to drill, using your 5g as a sump. The list goes on. 

One thought about your temp control problem though. Because of how a peltier works you _should_ be able to just reduce the voltage it's getting and thus reduce the peltier effect. Now this could be done with a simple potentiometer if the current draw of the pletier is very little, or with a computer fan controller (20 bucks) that uses more advanced techniques to control the voltage. So maybe just getting your peltier to say 36F on the surface then going with a more simple water delivery design will be the ticket.



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## Rain_Frog (Apr 27, 2004)

The other day, Marcos (blort) came up with a good idea, and sent me a drawing in a file attachment. Basically, a wide PVC pipe is capped with titanium and the peltier placed on the other side. The original idea did not have a true way to vent the heat, but you could connect a side pipe to the PVC, and a fan is placed on the top of the main pipe. Therefore, the fan draws air through the side pipe around the hot side of the peltier and out the main, like a chimney. I'm sure you can mount a small heatsink inside the wide tube of PVC. The larger pipe prevents the peltier's heat from potentially damaging it (if the pipe was narrower). And yes, I have seen peltiers offered on ebay WITH the temp controller for less than 20 bucks.

I could buy the peltier/controller, the power supply, and a small bit of titanium as well as a fan for probably less than $60. (the main expense comes from titanium, but with that much titanium, I could make several more small devices for probably less than $40 if i wanted). Epoxy would be used to seal the titanium to the PVC. You could just stick the end of the pvc into a sump.
I find this method very efficient, but what would the level of danger be? 
The main flaw is the level of danger involved. Al it would take would be a small leak/ flaw, or when the device ages and water could rush in from the bottom of the pipe up, electrocute the frogs and start a fire, but perhaps i'm too worried about it?

Perhaps if you get a small, hollow, aluminum/copper pipe and attach it to the titanium, that could work. Therefore, the peltier device itself would be attached to the aluminum pipe/ bar (thus, would be above the water line), in case the device would fail.

One question though, what's the best way to attach the peltier to the metal? Would I need to attach the aluminum bar/ copper to the titanium? I'd assume gravity would be enough to have enough contact.


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## defaced (May 23, 2005)

This is going to sound odd, but without knowing the resistance of the frogs, there's really no way of telling if a failure could be of danger to them. Generally anything below 40v is considered safe to humans, but since frogs most likely have more water in them, they will conduct electricity better, and that number could go down quite a bit. 

What I would do is read up on GFCIs and see if they will work on a 12v DC circut, or just experiment (post your finding, I'm interested in it too, just haven't had the time to search or try). That's the only way to be sure your frogs stay safe. If something happens and a short occurs it will cut power to the peltier. 

As for attaching your peltier, you will need a thermal paste http://www.newegg.com/Product/Product.asp?Item=N82E16835100007 used for computers and some way of solidly holding it to the Ti. Gravity won't be enough, and peltier's aren't heavy at all. The thermal paste will ensure good thermal conductivity to the Ti and your heatsink, which you must have as well or you will fry your peltier. You'll probably also find that you'll need a fan directly mounted to the heatsink to be able to move the heat effectively. Even then I'm not sure it will be enough because with the peltier inside a confined space it will be difficult to get cool air to it and thus it will overheat. 

Making the pipe longer and putting it between two pices of Al or Cu would be a good solution, like you mentioned. Something like this:








Say and 1-2 thick piece on the bottom and a 4-6 inch long piece on the top, both big enough to cover the whole peltier. This has no moving parts and keeps the peltier above the water line. With the larger piece on the top the heat will disipate fine and with a thiner piece on the bottom more heat will be pulled from the water. 

Here's a good deal on some Ti: http://cgi.ebay.com/6Al-4V-Titanium...ryZ61620QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

This isn't bad either, but it's probably overkill and would be difficult to cut without a good metal bandsaw: 

http://cgi.ebay.com/6Al-4V-Titanium...ryZ41963QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
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## booboo (Jan 22, 2005)

Where are you planning on getting your peltier part of it?


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## Rain_Frog (Apr 27, 2004)

You can buy peltiers off of ebay as low as $10, even including the controller, boo.


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## Rain_Frog (Apr 27, 2004)

Defaced (btw, if you don't mind, what is your name?), do you know where I can buy copper or aluminum "cylinders?" All I would need to do, is cap the wide cylinders and attach one side to the titanium plate, and one side to the peltier for maxium transfer. Its best if they are hollow and not solid aluminum/ copper rods as that is heavy and just way too expensive, plus that just makes more work for the peltier device itself.

Or, cut a few circles of aluminum/ copper sheet metal and sandwich inbetween them something, like tin foil? Or, perhaps cut cheap copper or aluminum tubing and bind them all together so the that they are inbetween the top copper plate (which has the peltier) and the bottom plate which has the Ti? Can I use thermal grease to bind the Ti to the titanium? I don't know how to weld.

Woah, the titanium I saw was $32. That is even a better price.

Ok:

On the low end, (minus the pipes and heatsink/fan) the price should be about $45, because I need to pay shipping. The high end, about around $70, but it all depends on what kind of deals I can get for titanium. But, with that much titanium, any additional device would probably be much cheaper.

Powersupply $10-20
peltier + controller $10-20
Titanium $10-30
Heatsink?
Aluminum/ copper pipe?
Thermal Grease?


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## defaced (May 23, 2005)

I don't mind at all, my name's Mike. Ti is titanium. I'm a welding engineering student so I'm used to using the elemental appreviation for most metals. Al is aluminum, Cu is copper and SS for stainless steel. I'm going to use those instead of writing out the names. http://www.onlinemetals.com/Is where you can get Al, Cu is going to be substancially more expensive for only a marginally more thermally conductive material, so Al is you best bet for you "cylinders". Cylinders in the metals are called rounds or round stock, square is the same. 

I think you've got the wrong idea about a peltier and under what conditions they work. Peltier's are under the classification of heat engines in physics. What this means is they produce heat that can be used to do work. A car engine is a heat engine, so is a steam boiler. However, with a peltier, unlike most other heat engines, it also produces extreme cold (-20 to -30 C), which is what we're interested in for this application. Most electrical components work best when they're cold, a pletier is no different. So that hot side (around 160 C depending on the individual peltier) of the peltier is very dangerous if it is allowed to get too hot, it will cause the peltier to fry and stop working. That's why in my drawing the hot side (the top side of the peltier) has a much larger piece of Al attached to it. It is very very very important that heat is moved away from the peltier. That is why if you look at an iceprobe there is a computer heat sink and a fan on one side, the hot side, and just a round piece of metal on the cold side. 

It's more important to keep it cold then it is to keep it warm. 

This is also why you must use thermal paste. Heat conducts best when it's in contact with something (air is a poor conductor of heat) so even though something feels smooth, there are still microscopic imperfections that will keep it from conducting heat effectively. Thermal paste fills in those imperfections and increases the thermal conductivity of the joint. 

Also, a peltier doesn't "work" the way you're thinking it does. Unlike an engine or a motor that will break if you try to work it too hard, a peltier is designed to move so much heat in a period of time. Because of the heat issue described in the last paragraph, working too hard for a peltier is when it gets too hot. So you want alot of metal on the hot side, and just enough on the cold side to be above freezing where it's submerged in the water to keep ice from forming. 

Now in your last reply you were thinking of buying round stock for your peltier. That's fine as long as the round stock covers the whole peltier. Because your peltier is square, your round stock's diameter will have to be the same as the peltier's diagonal measurement. To simplify things, and to keep weight down, I'd suggest getting square stock that's just slightly bigger than your peltier. I just checked eBay and it looks like 50mm and 40mm are pretty common sizes for peltier's. That works out to needing a 2" square for the 50mm and a 1.75" square for the 40mm. Here's a link to online metals square aluminum page. Just select your size and it will pull up price per foot and weight per foot. 
http://www.onlinemetals.com/product_search.cfm?step=2

I was looking at the heat controls for the peltier's on eBay (this one in particular (http://cgi.ebay.com/Peltier-Cooler-...7579322586QQcategoryZ4660QQrdZ1QQcmdZViewItem) and it's not going to work for your application. The temp controler is set to turn the peltier on when the temp probe gets to 40C and turn the peltier off when it cools to 30C. We're interested in 1-4C so that temp controler isn't going to work and the description says it can't be adjusted. Really the only way I can see to control this thing inexpensively is to adjust the voltage supplied to it (might work) or to make your Ti plate a Ti bar (or SS) and change how deep it is in the water. Not exactly high-tech but effective.



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## Rain_Frog (Apr 27, 2004)

Mike, do you have an idea how one could mount a peltier/heatsink combo into a vivarium hood? I'm looking into a window AC, but my bombina tank will STILL raise by 5 degrees from the water pump and the lights. Aluminum falling into the water would be less of a problem (i think) because they don't need a tank as sealed up (allowing for a ton of condensation), but forced ventilation into a tank could probably defeat the purpose of a peltier then.


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## Rain_Frog (Apr 27, 2004)

Here's a cheap idea, but its not as efficient, but probably could work well.

As an idea off the "chill box," what if the design was like those DIY beer coolers that you see? Basically, the peltier device would be ontop an insulated container, like a small Koolmate or something...something where the plastic is safe to use if aquarium water would come into contact with it.

As long as the sump is the appropriate size, the sump water shouldn't "rise" beyond a certain point in which it could come into contact with the peltier...no need for titanium or anything.

However, you might want to drill into the drink cooler in order to allow your Powerhead's hose to go through it. Basically, it would cool the air first, then the water.


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## defaced (May 23, 2005)

You said your FBT tank was above some other tanks right? Heat rises so why not put them on the lowest shelf possible and see what that does? 

If I'm understanding your idea right, then your peltier would have to touch the water directly, and that will fry your power supply. As for cooling the air, the basic elements for water cooling with a peltier will still be there, peltier, two heatsinks, thermal grease, but instead of a water pump you'll have a fan. 

Do you by chance have a fridge near the tank? You could take a long coil of tubing and put it in the fridge and run your tank water though it. That's a pretty easy to cool the water. Even a cooler filled ice will work instead of the fridge. 

Just some random ideas.



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## Rain_Frog (Apr 27, 2004)

> You said your FBT tank was above some other tanks right? Heat rises so why not put them on the lowest shelf possible and see what that does?


It is already on the bottom. While the room may be a cool 70 degrees, the tank will still hover 76 from the pump and lights. Cooling a room down to 65 degrees with an AC is very inefficient, rather uncomfortable for the keeper (who lives in the same room with the frogs) and too cold for the other frogs.




> Do you by chance have a fridge near the tank? You could take a long coil of tubing and put it in the fridge and run your tank water though it. That's a pretty easy to cool the water. Even a cooler filled ice will work instead of the fridge.


Thats virtually the idea I was trying to get across...but something smaller and more compact, like designing my peltier device now off of a portable beer cooler. 



> If I'm understanding your idea right, then your peltier would have to touch the water directly, and that will fry your power supply. As for cooling the air, the basic elements for water cooling with a peltier will still be there, peltier, two heatsinks, thermal grease, but instead of a water pump you'll have a fan.


Nope, the peltier would sit ontop the box's lid....a hole would be cut into the lid for the peltier's cooling element to be exposed to the air inside the box. The sump would consist of an insulated box, perhaps a small Koolmate or something that can hold beverages (therefore, safe for human consumption). This is the exact same principle as the "DIY beer coolers" you'll see on the net all the time. 

http://www.hackaday.com/entry/1234000083048949/

It additionally works the same way the fridge idea works. Therefore, the small amount of air inside the box gets cooled FIRST, then the water. But there is no messy tubing to deal with (which isn't a very good conductor). 

In a sump, it is easy to get a measurable water line, when the pump is running. However, I should shut the pump off to test how much water would fill the sump/ chill box when the pump is turned off, to make sure I never "overfill" the sump.

I have tested a similar, very effective principle once. When i had my epoxy tank up for a while (had to be taken down because it was leaking), i had a sump and overflow for my bombina. It sat right in front of the air conditioning vent. The water temp was always 66 degrees, as long as the AC was blowing over the sump. The tank air never got higher than 70, even with a 55 watt PC light. However, this design will incorporate a temp controller to prevent the sump from freezing or chilling the frogs.

Now, condensation can, and will form on the peltier device. The solution would probably be a small titanium plate siliconed to the hole in the lid of the sump box. The only reason why a plate is used, compared to the peltier beer cooler is because condensation will form and drip into the water. I do not know if anything from a peltier's cold side will be harmful if it drips, and to protect it, titanium plate is a good alternative.

I'll be buying a peltier pretty soon and a small cooler and test it first on a new tinctorius tank i will be setting up.


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## defaced (May 23, 2005)

I don't think I would have visualized that without a picture. As soon as I saw that I knew exactly what you were thinking. That sounds like the best idea of all. It's simple, cost effective, and the frogs are no where near the peltier. The cold side of a peltier is just ceramic which I would imagine wouldn't hurt the frogs. I'd clean it to get rid of anything that's on it of course.



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## Ed (Sep 19, 2004)

You know they already make and sell thermoelectric coolers like the ones by Coleman see http://www.cooler-store.com/thermoelect ... _2_ctg.htm. These are cooled and warmed by peltiers and as the bodies are plastic are easy to tap and install bulkhead fittings allowing for easy water circulation. 

I'm not sure why ten gallon tanks are so hard to drill as I have been drilling them off and on for almost 20 years and they have not been any harder to drill than any other tank. I would drill the tank and put in a piped overflow with the cooler as the sump and then have a aircooled pump as the return (this is the more expensive option). 

Ed


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## Rain_Frog (Apr 27, 2004)

Yes, I have seen those, but they all look pretty large and i don't really need the "food warmer" unless I want to keep some baby crickets or something. Most I've seen are in the $50-70 range, whereas the beer cooler (according to hackaday) is only about $35. (but a few other parts like a powerhead are not included)

I'll reconsider, but the design for the beer cooler is a bit more compact.
Perhaps Ed knows what the ceramic is made out of?

Just one thing...how do I wire the temp controller and adjust it? I don't know much about electronics except how to wire ballasts to CF, etc.

Now. What SIZE peltier do I need? I'm going to start with that new tinctorius vivarium. I want to cool water about 4-6 degrees. There will be around 1-2 gallons in the sump. The water will be piped up down a drip wall to spread it out and act like a nice heatsink.


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## Ed (Sep 19, 2004)

The come in sizes as small as 5 liter (1.32 gallons) (see http://www.cooler-store.com/vector_ther ... 6_prd1.htm for an example). I suspect that the difference between the cooling and the warming function is simply the result of the air circulation via the sides of the peltier as this allow for the warming and cooling. 

I'm not sure what ceramic you are referring to as I didn't see it on the web page. 


Ed


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## Rain_Frog (Apr 27, 2004)

Assuming if we make our own cooler from scratch, the peltier's cold side is ceramic, but I know the device itself is made from bismuth telluride. (is it?) I'm not sure if the ceramic cold side or the other parts of the peltier are 100% safe for coming into contact with vivarium water (corrosion, damage to the device, leaching of trace elements like the bismuth telluride, etc...considering vivarium water is acidic and rather hard).

Well, one could point out that the design anyway has the peltier elevated to cool the small amount of air in the box first above the water, but condensation and ice formation will certainly allow stuff to drip into the water system (so, distilled water from condensation. If this were aluminum for example, distilled water/ RO will corrode it).

Most peltier coolers were designed to where they cool contained beverages, not directly to where anything could drip onto food/ water. 

Problem with the these coleman coolers. They mount the peltiers on the side, not the top like in the diy model by Hackaday. Wouldn't that reduce the water level in my sump? (basically, to nothing)


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## Ed (Sep 19, 2004)

I don't know as I haven't actually had the chance to mess with one yet, my knowledge of them came from an old post from the ICPS listserve. There were too variations on this (if I am remembering corrctly), one a guy used a large one to house highland Nepenthes and and another guy dismounted it from the cooler and mounted it on his Edwardian Case for highland Nepenthes. The reason they did this was because these units have thermostates already included and werer already wired up and this allowed for a little more control of the temperatures as opposed to wiring them in from scratch. (Also you can readily buy converters allowing them to be plugged into the wall). 

With the coolers, even if they are mounted on the side, you could remove the aluminum liner, and line the thing with acrylic which could be attached directly to the plastic liner with acrylic glue and then build a wall to prevent the water from contacting the chiller or use a larger one and just drop a smaller tank into it as a resivoir and plumb through the top. 
With the coolers as these are made to control the temps in an enclosed space there should be something in there to deal with the condenstation from humidity and either prevent it from contacting the chiller or to wick it away. 

There is a guy on caudata who just mounted it vertically inside his tank 
see http://www.caudata.org/forum/messages/7 ... 1123636262

Here is another alternative using a room dehumidifier as the chiller. 

http://www.fnzas.org.nz/fishroom/2-vt6927.html?start=15
Ed


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## Rain_Frog (Apr 27, 2004)

Yes, I read both of those. I made a chiller from a dehumidifier (for the clawed frog tank, 100 gallon), but that is way too large for such a small application in this case. 

I find the way the guy mounts the iceprobe directly into the tank to be very dangerous. All it takes is that to fall into the tank or a frog to jump ontop of the fan...and well...

I'm trying to avoid buying an iceprobe, not worth the cost unless you buy a used one.

You sure weldon will bond to that type of plastic in coolers or shoeboxes? It works great with acrylic, but it won't adhere to every type of plastic though. I'll do a test on a shoebox to see if it melts it (it will melt/weld plastic dixie cups though).


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## Rain_Frog (Apr 27, 2004)

Some of the Ti on ebay is 8% magnesium. Will magnesium degrade the properties of Titanium?


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## defaced (May 23, 2005)

Well that depends on what property on the Ti you're interested in. The magnesium is added for a reason; what reason I'm not sure though. Since you're interested in Ti's thermal conductivity property, it's going to make very little difference. I do know that Ti-6-4 is the most commonly used grade of Ti, and the same grade that's used for implants, so it's definately safe. As for the magnesium alloy, I'm not sure; I'd need more info, specifically what else is in the alloy.



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## Rain_Frog (Apr 27, 2004)

http://cgi.ebay.com/Titanium-Sheet-TI-M ... dZViewItem

Its the same Ti you and I both saw on Ebay. I believe it has been used for air crafts?


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## Rain_Frog (Apr 27, 2004)

http://www.smallparts.com/products/desc ... s/smti.cfm

this is the original place I looked into. It is 99% titanium alloy, and not much more expensive for the thinnest sheet. How strong is .035" Mike?

BTW, did you get my PM?


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## defaced (May 23, 2005)

Yea I got your PM. I must have accidently unchecked the option to have me notified by email if I have a PM because there were a few waiting on me. I'll get back to you on it. Hopefully tonight, if not then tomorrow night. 

.035 is pretty thin. That's about 1/32 of an inch. I'd personally go with something thicker because it's easier to work with, harder to bend. The .065 is just a tiny bit bigger than 1/16", that's what I'd go with. 

The CP Ti you linked to on small parts is fine. It's what's used as a base for Ti alloys. The Ti-Mg alloy on eBay is something special. I can't find any information on it. That's even checking Cambridge's online data base of phase diagrams clicky. How much is Ti-6-4 (6% Aluminum, 4% Vanadium)?



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