Reptile & Amphibian Forums

I'm experimenting with a thermoelectric (Peltier) chip to provide a cool spot in a cage. I'm hoping to hear from others that are thinking along these lines so we can compare notes and maybe come up with something practicle and useful.

This is the Peltier chip and heat sink as it came from Carl’s electronics, and the big piece of aluminum I am using for the cold sink.

This shows the cold sink with a piece of stick on tile used as insulation, this side will be bolted to the wooden shelf.
The chip assembly gets coated with thermal grease. The holes are metric. The cold sink will be under the shelf, the chip goes through a hole cut in the shelf and the heat sink and fan will be above the shelf.

This is view from below, with cold sink bolted in place. The shelf is in a corner of the cage.

This is the shelf installed with the Peltier and fan assembly bolted on. The big hole in the corner of the cage is to vent the heat.

This is the view from the back of the cage.

This shows with the cover screwed in place. You can see the cold sink underneath.

This is my set up with two electronic thermometers, one probe under the cold sink, the other at the other side of the cage.

Showing the thermal gradient expressed after just a few minutes. Good six degrees very easily.

The vent box along the top uses ventilated metal used for soffets, it’s six inches wide. There’s .75 inch area inside for air to vent through a round hole at the left end. I’m using a bathroom vent fan mounted above that air chamber, vents out the back of the cage. The rest of the space provides a place to conceal the wall warts that run the chip, and the small 12 volt fan.

This is the main vent fan

This shows the back, the small chip fan in the corner, the space for the wall warts and the other end has the exhaust fan. The vent in the back is for incoming air.

From the front, obviously. The plastic door track you see at the bottom is just set there, I still haven’t decided what door system to use, rollers or whatever. This was mainly to experiment with the thermal gradient possibilities. So far it is very promising, but I’d have to run it a few weeks before I would actually put something in this thing.

Hope this inspires more experimenting and we come up with something that provides better maintenance for our little snakes!

Thanks for looking, and all the contributions that inspire.

There was a lot of talk about these in the zoo community when they first came available and affordable. Obviously a lot of potential application in the herp world.

Don't know what ever came of it (the talk) but I'm glad to see you're giving it a shot. I would really appreciate it if you kept us posted on your project. Doubt I'll ever need one but I'm still interested in the potential.
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Currently keeping:

6.10 Gonyosoma oxycephala (Javan, mixed colors)

1.1 Philodryas baroni

1.0 Rhodesian Ridgeback

I have been dreaming about something like “cool” tape instead of heat tape for dealing with heat issues. You can see by the picture of the two thermometers, the ambient temps I am regularly dealing with here, 89 degrees, and this is without the glass installed yet. Just having a spot about eight degrees lower available to the snake could mean everything. It’s a start!

I believe that this is a needed application for many of us whose snakes are kept in rooms that get very warm during the hot season. Since Peltier modules have no moving parts (as opposed to A/C), I would imagine they would last alot longer.

What is the power draw on the unit you show there?
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Mark

I started out with a universal wall wart power supply with selectable voltage from 3 to 12 volt @ 300 mA. I can switch the pos and neg with a switch too. That changes the chip from heater to cooler. I was experimenting with it and burnt it up at 12 volts. I need to have more amps, the chip is rated 50 watts and .5 amp to 4 amps. I’m now using a 12 volt 1000 mA (1 amp) wall wart. It’s a work in progress. I don’t want to cool twenty five degrees, just about eight would be good. I’m an absolute noob with electricity, so I may burn through a few more wall warts and various other parts before I have it right. What an I say, it amuses me.

Well I commend your indulgence.

Studies of gila monsters in the wild (wow, what a subject change!) have shown that they alternate between basking near the surface and getting to 90 degrees and then taking refuge deep in burrows where their body temp gets down into the 60s. And for many snakes, that is likely what goes on as well. With the Peltier application, something like this can be achieved. Fun stuff, I say. And for breeding Gila monsters where babies sell for $1200 a pop, well worth the effort.
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Mark

EXCELLENT!!!!!!!

Great thread Upscale.

I've been researching a bit how to install a peltier in a glass frog tank. I wondered how/where to mount it and spread the cooling effect instead of a very small frozen surface... I want to be able to lower the air temp of the tank about 8-10 degrees and it's a a 54 or 60g tank with high humidity which holds heat....

I was origionally considering the cold side with a finned heatsink with fan to blow cool air in the tank and covering the assembly with screen to keep the animals away from it. I like your idea much better though. I may add a small fan next to the cool sink on a timer to blow cool air around the tank for short periods of time still. I dunno yet.

Questions-
How cold is your aluminum heat sink?
What are it's dimensions?
What is that "extension" on yours? The peltier's I've seen are only the element itself which is just a flat piece about 1/8" thick. That "extension" on yours makes mounting a breeze....
Are you going to rig up some type of thermostat for it?

Glad to hear someone is interested in this sort of project. I was a little surprised nobody seemed interested. I can tell you, I think getting the wine cooler and taking it apart and experimenting with that would be the way to go. You will save money at that price. I think you will find the wine cooler does use a finned “cool sink” on the cool side and a fan so the air is circulated around the box. It is designed to pump the heat from the air in the box to the outside, so you have to move a lot of air around. With my design, I just used a bar of aluminum that is (I’m guessing because I didn’t measure it) I think it’s about four inches by eleven and a half and a quarter inch thick. By not having a fan on the cool side, I am just cooling a spot rather than trying to turn the whole cage into a cooler. I am still experimenting, but have got it to provide just a slightly cooler area, like four degrees. I have created a hide by walling up some Aspen bedding to try and see what that would do, and it does provide a nice cooler spot there without cooling too much. I have thought about just mounting the whole wine cooler next to a cage and providing a connecting tube or something too. The nice thing about the wine cooler is it has the control board, which is a million little diodes and capacitors and all that stuff I barely understand. My wine cooler has a light, temp controller and all that, which would be more money to figure some system out.
I got the whole peltier, hot sink, fan and cold side aluminum (not including the bar I attached) from Carl’s Electronics, you can find them online easy. http://www.electronickits.com/
I hope you try some things and share the results in the forum. Good luck!

Here’s a few updated pictures of my TEC cage project. The idea is to provide a cooler area within the cage so the animal is able to thermoregulate (choose between a warm and cool spot in the cage).

Here’s a picture of the cage. The fake rock in the corner hides the heat sink cooling fan. The 12 volt heat dissipation fan is provided from a computer chip cooling assembly.

This shows the fake rock removed to show how the fan assembly is incorporated into the cage. The cooling sink and 12 volt fan are mounted below the shelf. The hot air vents out the back corner of the cage behind the angled section..

This is the aluminum cool sink with the fan assembly mounted, view from below as it is inside the cage under the shelf. The aluminum is four inches by about seven inches, one half inch thick.

This is the heat dissipation “cool pipe” assembly and fan. It has a copper base that sits right on the hot side of the TEC. The cool side sits right on the aluminum block cool sink.

This is the TEC chip looking through the shelf, as it sits on the cool block. It is well insulated from the hot side. Note the thermal paste. The heat dissipation assembly sits on here and is screwed down tight.

This is the occupant of the cage! He deserves a break from the heat every now and then!