Instructables

Is it possibly to take apart a fridges Cooling element for use elsewhere?


I am hoping to make a fog chiller for smoke machines.
From the designs I have seen they have been using ice although this isn't very effiecient for the how I am going to use it.
So would it be possibly to take out the cooling element from a fridge (I have one lying around) and use it to cool other things?

All comments are welcome

Thank You

Oscar

alexhalford4 years ago
In theory, yes; in practice, it's a lot of work.
Fridges (I am assuming you mean a normal sized one, rather than a mini-fridge) cool in effectively the same manner as an air conditioning unit. A pump compresses refrigerant on one 'side' of the systen, and reduces its pressure on the other. As a result of the gas laws (temperature related to pressure etc, the same reason that if you use a can of deodorant, it feels cold afterwards), this leads to a temperature differential.
Science aside, you would have to remove the entire cooling system without releasing the pressurised refrigerant. Older fridges use CFCs, these have been made illegal due to their nasty habit of destroying the ozone layer; as a result, if you do accidentally release the gas (assuming it is an old fridge), you will be committing a crime (they have to be disposed of in a special manner).
In any case, using a fridge for this would be an extraordinary amount of effort.
In lieu of dry ice, have you considered a peltier heat pump? These use the peltier effect to create a temperature differential. If you stack two of them with adequate heatsinking, you could probably achieve about 80-100K below room temperature.
oscarthompson (author)  alexhalford4 years ago
Yes, I knew there was issues about the gases, I found out a while ago on another project.
Anyway, I was going to ask about petlier cooling plates, I didn't know if they would be effiencent enough? I was hoping to attach them to my metal pipe ( for the smoke) with the heat sink paste stuff' or I could use your idea? What would be better?

Thanks for the comment

Oscar
I will start by mentioning that heat pumps can run at about 60 watts, so if you put a couple next to each other, that's a fairly respectable power level.
Another important point about them: peltier units work as well as you make them work. They will generate a temperature gradient (power levels allowing of course) of about seventy degrees (C/K), this means that you need to cool the hot end (with a fan and heatsink or something) of you'll just end up with one warm plate and one very warm plate.
As for efficiency, the cooling device is attached to a fog machine, which is (I assume) plugged into the mains, so efficiency is more of a desire than a need, you'll certainly have enough power to run it.
Attaching them to a pipe may require some machining. The pipe is (I assume) circular, the peltier elements are flat. You'd need an awful lot of paste and some method to keep it in place. Personally, I would fashion a small-ish rectangular box with the peltiers on the base and a circular port on one end for connecting to the fog machine. This would need to be made of metal for thermal conductivity. Remember, lots of metal volume, and most importantly, as much surface area as you can manage.
AHalford.
oscarthompson (author)  alexhalford4 years ago
Thanks for your comment. I'll go with your idea.

How many peltier heat pumps should I use. The wattage being 60w each. I am planning to run them from a computer psu.

Oscar
lemonie4 years ago

Dry ice perhaps?

I don't think this is the right idea.

L
oscarthompson (author)  lemonie4 years ago
Yeah.. There are alot of issues regarding it.. I didn't think dry ice was commercaily available though?

Thanks for the comment

Oscar
Its available, or you can make it from a CO2 bottle, but its not really needed to do this. Ice is cheaper !
oscarthompson (author)  steveastrouk4 years ago
Cool :) Thanks for the comment.

Most places which sell bottled gasses (for welding, for soda machines, for balloons, and so on) should also be able to supply dry ice.
Do you mean a Peltier/thermoelectric cooler ? If so, yes, but you won't get anything LIKE enough cooling to make it worthwhile I'm afraid.

Steve
oscarthompson (author)  steveastrouk4 years ago
Oh.. Are there any alternatives, I can only think fans..

Thanks for the comment
Get a large garbage can, and a long length of aluminium furnace pipe - say 6" diameter. Coil tube in garbage can. Ideally, arrnage the pipe to come out through the wall of the base of the can.
Seal well
Fill can with water. Add quantities of ice.

Inject smoke into top of pipe.

Steve
oscarthompson (author)  steveastrouk4 years ago
Oh Right!
Thank you!