What liquids have the ability to freeze quickly?

[lgaa]

quickly cooling substances...

I'm on a project using peltier cells, and i know that there are some cells that can freeze water in 20 seconds... My question is, is there any substance that can freeze as quickly as the peltier cell or just freeze quickly?
I just need a substance or material whit the ability to freeze quickly. : D :rofl:

 

[russ_watters]

Liquid nitrogen will do it.

 

[lgaa]

tnks russ,... but what I look, is a substance for me to be able to freeze it in this time.

 

[russ_watters]

Could you rephrase your question or be a little more specific please. It doesn't make much sense.

 

[MagnetDave]

Your question is extremely general to the point of being unanswerable.

How much water do you want to freeze how fast? This would be a good start.

 

[DaS Energy]

Not sure if it can be called a substance but Co2 flash freezes to minus 40*C , commonly known as Dry-Ice.

I'm on a project using peltier cells, and i know that there are some cells that can freeze water in 20 seconds... My question is, is there any substance that can freeze as quickly as the peltier cell or just freeze quickly?
I just need a substance or material whit the ability to freeze quickly. : D :rofl:

 

[lgaa]

I'm sorry.

This one well, it’s that not to write itself very well in English.

My question is, there exists a substance that freezes rapidly with the decrease of the temperature with the peltier cell, at least in 20 or 30 second, which it lasted cooling the peltier cell?

 

[lgaa]

Quantity to freeze will be an approximate volume of 8cm. Cubic.

Dimensions of 4 x 4 x .5 cm.

 

[Feldoh]

If you had a container of water with a volume of 8cm^3 you could probably cool it pretty fast with liquid nitrogen which is < 77K in temperature. If that's not fast enough perhaps liquid helium would do the trick.

Only problem is that if liquid nitrogen doesn't work fast enough liquid helium is expensive to work with. In terms of cost LN is like the Natural Light of low temp reservoirs where as LH is like a nice bottle of scotch...

 

[MagnetDave]

That much water will be hard to freeze that fast, and it has more to do with the water. Water has a limited thermal conductivity and a large specific heat and specific heat of fusion and you have to absorb quite a bit of energy to get that water frozen, and then you have conduct the energy out of the water very rapidly.

For something like that, my approach would be to get a good heat sink material (a block of aluminum will work nicely) and deep-freeze it in liquid nitrogen (meaning submerge it until it stops boiling) and then put the block of aluminum against your water container. That will pretty much draw the heat out as fast anything practical and should be much faster than a Peltier cell.

 

[AndyNewton]

We need to explore what your question means.
Is this what you are doing?...

You are applying electrical power to a Peltier cell.

The electrical power is causing the Peltier cell to cool.

You have a small flat dish in contact with the cell.

The dish will hold about 8cc of some liquid.

You wish to select a liquid that will freeze rapidly.

You are asking the forum for suggested liquids to use.

What liquid will freeze fastest?

I assume from reading your original question that you have setup the experiment equipment and you have noticed that the cell cools down to below zero degrees very quickly when there is no liquid in the container. With water in the container is takes a much longer time for the water to freeze.

Is all this making sense so far? :-)

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If my understanding of your question is correct then I can suggest a few ideas as below.
If your question is different then do try asking again.
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The process occurring inside the Peltier cell is capable of absorbing heat at some rate fixed rate - some number of joules of heat energy absorbed per second.
The first result of absorbing heat will be a drop in temperature. The rate of change of temperature will depend on the heat capacity of whatever objects are being cooled. If the only object being cooled is the Peltier cell itself then temperature can drop rapidly. If the object being cooled includes a mass of liquid then the rate of change of temperature will depend on the Heat Capacity of the total mass of liquid.
The Specific Heat Capacity of water is about 4.2 joule per gramme per degree Kelvin. Any liquid with a lower Specific Heat Capacity would change temperature more rapidly than water. (If all other factors are equal.)

The second result of absorbing heat is the freezing of the liquid (if the temperature drops low enough). The rate of freezing will depend on the Latent Heat of Fusion of the liquid (If all other factors are equal). Water releases an unusually large quantity of Latent Heat when its is changing from liquid to solid. The Specific Heat of Fusion for water is about 334 joule per gramme.

Your ideal liquid would have a low Specific Heat Capacity, and a freezing point above zero degrees (so it reaches freezing point more rapidly), and a low Specific Heat of Fusion.

Now what might that be? Some sort of wax or oil...? Butter, ghee? Ideas anyone?

 

[lgaa]

thank you all... very good ideas...

And yours Andy,
understood my point,
and I clarify many doubts,

I now hold to get that liquid having a low specific heat capacity, and a freezing point above zero degrees, to get faster freezing .
Now my question is: do you know that substance with these characteristics explain Andy?

 

[AndyNewton]

I now hold to get that liquid having a low specific heat capacity, and a freezing point above zero degrees, to get faster freezing .
Now my question is: do you know that substance with these characteristics explain

There is no obvious choice of liquid that I can think of. You will need to collect together and compare the data on heat capacity, latent heat of fusion, and freezing point for various liquids.
I think the freezing point temperature will be the biggest problem. Most liquids have lower heat capacity and lower latent heat of fusion than water, but few liquids have a suitable freezing point temperature.

Here are some links to get you started. Each link contains a table of common liquids.

http://en.wikipedia.org/wiki/Specific_heat_capacity#Table_of_specific_heat_capacities"

http://en.wikipedia.org/wiki/Latent_heat_of_fusion"

http://www.engineeringtoolbox.com/freezing-points-liquids-d_1261.html"