Hypothetical cold box

[ChrisFL]

So many of you are familiar with my cold tank monstrosity that uses a compressor/refrigerator:

http://www.slippertalk.com/forum/showthread.php?t=25452

So I work with cry cooling and heat removal a lot during isotopic analyses. I know a lot of people have wondered whether peltier cooling is possible. Most people I know that have tried it haven't been very successful. I have the parts and an idea that would allow me to try to make a system that would integrate directly into 10 gallon vert conversions like this:

http://www.junglebox.net/product/300.html

Do you think people would be interested in buying a kit that would allow you to take a ten gallon vert and grow cold growing minis in it?

 

[Ozpaph]

You can only try. It will largely depend on cost and what sort of 'warranty' you offer.

 

[keithrs]

I think a bigger tank should be in order..... If it works reliably in a 40 gal. You may have something.

 

[NYEric]

it could sell, depends on the price, however if it works it would fill up w/ plants very quickly at only 10 gallons.

 

[keithrs]

When I was thinking of using peltiers to cool my terrarium I was going to use a water block with the peltier cooling the water block. From there I was going to use a small water pump to pump alcohol to a CPU radiator with a 120 mm fan to blow the cool air in. I was looking at a water block that could hold 2 400 w peltiers. I was also thinking of reversing polarity to heat.

 

[Rick]

I may not be totally up on the terminology.

Are peltiers those thermoelectric heat pumps for computers?

If so I used an air driven system of those once and had a few problems namely that 1) it was really expensive (like $600 for both the appropriate sized cooling unit and power supply), and 2) it would also act as a dehumidifier by condesing out all the moisture from the fogger or wet pad.

It was always a constant dripping mess too.

So I also thought about a way to cool water that I could pump to a "swamp cooler" or wet pad type of arrangement. (I think what Keithrs is coming up with)

It turned out that a German aquarium equipment manufacturer makes a small tank chiller that fit the bill for about $150 if I remember correctly. I believe it uses peltiers on a stainless or titanium water block. I think its rated for up to 20 gallons (???). My indoor box is roughly 3' X 3' X1' deep.

I put a 3 gallon sump in the box, using a small submersible pump (that actually came with the chiller) to send the water to the chilling unit, and then the water goes up to the homemade wet pad/fan box. The wet pad is located above the sump and gravity feeds the water back to the sump.

It works OK.

It's been a while since I did all this, so I may be totally loused up on the prices.

 

[keithrs]

I may not be totally up on the terminology.

Are peltiers those thermoelectric heat pumps for computers?

If so I used an air driven system of those once and had a few problems namely that 1) it was really expensive (like $600 for both the appropriate sized cooling unit and power supply), and 2) it would also act as a dehumidifier by condesing out all the moisture from the fogger or wet pad.

It was always a constant dripping mess too.

So I also thought about a way to cool water that I could pump to a "swamp cooler" or wet pad type of arrangement. (I think what Keithrs is coming up with)

It turned out that a German aquarium equipment manufacturer makes a small tank chiller that fit the bill for about $150 if I remember correctly. I believe it uses peltiers on a stainless or titanium water block. I think its rated for up to 20 gallons (???). My indoor box is roughly 3' X 3' X1' deep.

I put a 3 gallon sump in the box, using a small submersible pump (that actually came with the chiller) to send the water to the chilling unit, and then the water goes up to the homemade wet pad/fan box. The wet pad is located above the sump and gravity feeds the water back to the sump.

It works OK.

It's been a while since I did all this, so I may be totally loused up on the prices.

Rick, They are thermoelectric devices(heat pumps if you so wish) that can cool, heat, or make there own energy if hot and cold are applied to opposite sides.

There fairly inexpensive to the range of $10-30 bucks or so. It's common to use aluminum or copper for cooling plates as they transfer thremoenergy better than SS or Ti. You can rob a power supply from a junk computer that most of us have laying around.(Just make sure your responsible and recycle the rest of the computer)

I have two tanks (60? and 70 gal.) that I plan to use as display cases for some minis. I'm afraid Peltiers wont have the cooling power. So, I've pulled an a/c unit out of an old office trailer that my work junked. I plan on using it to chill some sorta coolant and then circulate that to the two tanks that will have a fan that's thermostatically controlled.

Sounds good in theory....:evil:

 

[Rick]

http://www.aquaeurousa.com/Chillers.htm

The unit I got was from Aqua Euro, and it was the 1/13 hp unit.

Actually its about $350 and not $150.

 

[goods]

Rick do you have pictures of your set up? I think I'm following what you're saying, but it would be interesting to see the whole setup.

Keith, take a look at this thread: http://www.cpukforum.com/forum/index.php?showtopic=28146&st=0

Sorry for the highjack Chris!

 

[keithrs]

http://www.aquaeurousa.com/Chillers.htm

The unit I got was from Aqua Euro, and it was the 1/13 hp unit.

Actually its about $350 and not $150.

I have looked into those types of chillers.... I believe they where made for the salt water aquarium market which is why they use SS or Ti for the cooling element.

 

[keithrs]

Rick do you have pictures of your set up? I think I'm following what you're saying, but it would be interesting to see the whole setup.

Keith, take a look at this thread: http://www.cpukforum.com/forum/index.php?showtopic=28146&st=0

Sorry for the highjack Chris!

Goods, Thanks for the link!

 

[keithrs]

There's a link Ya'll may find interesting.....

Peltier elements to cool terrariums

 

[newbud]

Great discussion guys. Quick question along this line. I pulled my computer fan out of old computer and the power supply but I can't find the two pins on the 24 pin plug that switch the (computer) fan on. Do you happen to know which one it is. I went to asus but they weren't any help with the switch schematic. I guess I need to find the power supply manuf. and see if they have a schematic. If you know a short cut I'd appreciate it. Thanks

 

[Paphman910]

Great discussion guys. Quick question along this line. I pulled my computer fan out of old computer and the power supply but I can't find the two pins on the 24 pin plug that switch the (computer) fan on. Do you happen to know which one it is. I went to asus but they weren't any help with the switch schematic. I guess I need to find the power supply manuf. and see if they have a schematic. If you know a short cut I'd appreciate it. Thanks

Why don't you get an old cellphone adapter jack that is 6 to 12 V DC!

Paphman910

 

[ChrisFL]

Liquid cooling system for a peltier gets the system colder than -5 F. The water in the heat removal loop stays 92.2 F.

 

[ChrisFL]

Equilibrium cold side temperature of a liquid cooled Peltier device.

 

[keithrs]

Great discussion guys. Quick question along this line. I pulled my computer fan out of old computer and the power supply but I can't find the two pins on the 24 pin plug that switch the (computer) fan on. Do you happen to know which one it is. I went to asus but they weren't any help with the switch schematic. I guess I need to find the power supply manuf. and see if they have a schematic. If you know a short cut I'd appreciate it. Thanks

You can use any 12v+ and any ground pin off the supply.....The power supply can't switch the fan off and on.... The mother board does that. Most people have the fan running 24/7.

Is there something special your trying to do?

 

[likespaphs]

does it do anything to humidity?

 

[Rick]

I finally got around to taking a picture of my setup.

Reservoir sump is blue tank on the bottom. Feeding through the chiller (outside of box) to wet pad/fan inside the box. Water from the wet pad gravity spills back into the sump below it.

The wet pad is made from a pvc electrical box, cut up to hold a humidifier pad for an air conditioner. Mini household box fan pulls air through the wet pad.

 

[keithrs]

I finally got around to taking a picture of my setup.

Reservoir sump is blue tank on the bottom. Feeding through the chiller (outside of box) to wet pad/fan inside the box. Water from the wet pad gravity spills back into the sump below it.

The wet pad is made from a pvc electrical box, cut up to hold a humidifier pad for an air conditioner. Mini household box fan pulls air through the wet pad.

That's interesting.....

I never really thought about using a wet pad!