How to make an instant Water Cooler

[Ahmed]

Hello

 

I want to make an instant water cooler (electric) with inlet water temperature of about 35-50 C and output temperature of roughly 8 - 18 C.

 

I have the equipment and facility available to do the experiment. It would be great if someone can help me in this regard.

 

Looking forward for possible solutions.

 

Thanks

Ahmed

[insane_alien]

instant eh? afraid that would require something below absolute zero. infinitely below.

 

you can however get one thats pretty quick. using a peltier device and a large aircooled(probably with fas) heat sink would probably do the job for you. depending on room temperature the peltier device could be unnecessary though it would significantly decrease the size of the exchanger.

 

also, what sort of flowrate do you need? is it even a flow system?

[CaptainPanic]

Peltier is an easy way to cool (and heat) things electrically.

 

It creates a cold and a hot surface. So, you need to get rid of the heat somehow.

 

Also, if you're planning to make drinking water, make sure your materials are food grade.

[Snail13579]

ooo liquid nitrogen, make it so every so often liquid nitro is added into the water and BOOM u got cold water, or perhaps frozen water

[insane_alien]

Snail, not only is that an incredibly inefficient way of cooling something(it won't work the way you think it will) all it will result in is liquid nitrogen getting flung everywhere.

 

think throwing water on a chip pan fire but the temperature range has been shifted somewhat.

 

very little water will actually get to the point of freezing except the droplets that get thrown off by flash boiling liquid nitrogen.

[DrP]

Snail, not only is that an incredibly inefficient way of cooling something(it won't work the way you think it will) all it will result in is liquid nitrogen getting flung everywhere.

 

think throwing water on a chip pan fire but the temperature range has been shifted somewhat.

 

very little water will actually get to the point of freezing except the droplets that get thrown off by flash boiling liquid nitrogen.

 

What if you bubbled the N2 through the water from the bottom at a reasonably steady rate (with stirring so the water wouldn't freeze up the pipe of course).. I reckon you could make a Slush Puppy in this way. (?) Heston Blumanthal makes ice cream with liquid N2. Even so.... I agree it would be inefficient. Someone asked me for ideas for an ice maker once - I also suggested a high powered Peltier or quick release of a pressurised CO2 capsual through a small nossel (bit like a snow maker).

[insane_alien]

i doubt it.

 

there are far better ways of doing it. and seeing as we don't know the application, a non contact heat exchanger is probably a better idea than a contact one.

[Snail13579]

i've seen in myth busters for the fastest way to cool a beer, i think it was by using the fire extinguishers.

[CaptainPanic]

Ahmed (the topic starter) actually specified the outlet temperature. I seriously doubt that you have any control over the temperature of your water when you use a fire extinguisher, or even when you bubble liquid/evaporating nitrogen through water.

 

I've worked on a setup which was able to cool water from 18 deg to -4 (it contained a lot of salts) in about 2 seconds. That's by using a standard liquid/liquid heat exchanger... try to beat that with a fire extinguisher. I haven't seen the mythbusters episode, but they probably wanted to keep the beer in its can while cooling it.

 

A non-contact heat exchanger (meaning that the water and the cooling agent are not in direct contact) is definitely the way to go if you want to have something serious. (If you just want a single cool experiment, then solid CO2 or liquid N2 is probably fun if you do it safely).

 

So, option #1 is the peltier. It does not leak, does not contain any weird gas, and consumes only electricity.

Option #2 is the non-contact heat exchanger. An example is your fridge. If you were to bring the water into direct contact with the cooling elements inside the fridge, then by adjusting the flow of the water you can adjust the temperature.

[iNow]

I like the option above for it's speed, but a simpler process is available if you can give up some time.

 

Why not something like they use when brewing home beer to cool the wort? You get a small diameter copper pipe (like 1/4"), coil it up relatively tight, place the coil in a rather large barrel of ice water, then flow your liquid through the copper pipe. As it passes around each the bends in the pipe (which is suspended in a very cold ice bath) it gives off it's heat. By the time it's gone from start to finish, it's cooled markedly.

 

Then, to get the temperature correct, you just shorten or lengthen the pipe.

 

 

EDIT: Nevermind. I just saw how cold the OP wants the output to be. Please disregard.

[insane_alien]

iNow, varying the flowrate is a much better option than varying the length of pipe. you can't vary the length of pipe on the fly to cope with fluctuations in input temperature can you?

[iNow]

Indeed. It would be easier to vary flow rate as well (as opposed to wasting so many materials always shortening your pipe)... also, once it's shortened, it can't be easily made longer again. Good call, IA.

[DrP]

OK, slap me if this is stupid, but couldn't you have the water in under pressure and then have it exiting at pressure through a small nossle. As the water exits the nossel it will cool due to adiabatic expansion. You could adjust the pressure of the water to get the temperature right - higher pressure = faster expansion and thus cooler water. (?)

 

I'm sure you could do some maths to work out what the pressures should be and the nossel sizes (or you cold just play arround with it and see what happens by trial and error).

[insane_alien]

as water is a liquid, it is fairly incompressible. the temperature difference will be minimal.

 

also, if it is exiting with a lot higher pressure it will tend to disperse into a spray, this will result in the liquid ending up at room temperature as it will have a high heat transfer area.

[DrP]

as water is a liquid, it is fairly incompressible. the temperature difference will be minimal.

 

I'm not so sure it wont work if you force it through the right nossel.

 

also, if it is exiting with a lot higher pressure it will tend to disperse into a spray, this will result in the liquid ending up at room temperature as it will have a high heat transfer area.

 

He only wants it below 18C - I'm starting to think this could work, but I can't find anything practical about the AD expansion of water at the moment, just info about certain type of nossels. Will search harder when I'm not supposed to be working. Anyway, the spray could be quickly collected into a container so it is back to a full body of water again within a couple of feet from the nossel.

 

(:embarass:Cringes as he realises he has spelt nozzel wrong about 5 times already )

[insane_alien]

it doesn't matter, if it has turned into droplets it will be at room temperature. we do not know what room temperature is. it could very well be above the required temperature.

[CaptainPanic]

I think that when you compress water, and force it through a nozzle, you will actually end up heating it up. The compressor will heat up the water, and although the minimal expansion when it exits the nozzle might cool it down a bit the net effect I think is heating it up.

 

The following formula comes from a book on homogenizers. These are used in biotechnology to break up cells (kill em!) in order to release for example proteins that are locked up inside a cell.

 

[math] \Delta{T} = \frac{\Delta{P}}{\rho{C_{P}}}[/math]

 

The only effect that can cause any cooling after you spray water through a nozzle is when you evaporate a part of the water. (Of course, when you have small droplets, evaporating becomes easier... but you should realize that you need a constant flow of fresh (dry) air and you will lose a part of your water).

 

I think iNow made the best post here so far. Why reinvent the wheel? A beer tap is exactly what you want: it can cool water (beer = mostly water) in a matter of seconds. It is food-grade.

[DrP]

Yea - you are right guy's, thanks. The ways you mentioned were best. Snow makers do work in a similar way to what I suggested, but they use compressed gas expansion next to the nozzel to freeze the vater vapour spray into small ice crystals. I was just thinking allowed.

[chemeng]

why does the popcorn swells, which is the chemical that makes it to swell on heating?

[iNow]

why does the popcorn swells, which is the chemical that makes it to swell on heating?

 

Hi chemeng,

 

It's not really a chemical which makes the popcorn kernel pop, it's just water. When the water heats, it creates pressure. However, since your question is a little off topic for this thread, I'll give you the link below so you can read more for yourself. Enjoy.

 

 

 

http://www.nasa.gov/audience/forkids/home/popcorn.html

 

Only popcorn kernels can pop, and the secret is water. Each kernel contains a small amount of water stored in a circle of soft starch inside the hard outer casing. When heated to around 450? F, the moisture turns to steam, creating pressure within. As the pressure builds, the casing eventually gives way, and the kernel explodes and pops, allowing the water to escape as steam and turning the kernel inside out.

[insane_alien]

It's not really a chemical which makes the popcorn kernel pop, it's just water.

 

explain to me how water is not a chemical?

 

and what has this to do with the cooling of said chemical?

[iNow]

explain to me how water is not a chemical?

 

and what has this to do with the cooling of said chemical?

 

I just knew I was going to be nailed for that. I should know better.

To your second question, you'll notice that I reminded the person asking that it was "off-topic" in my own post.

 

 

 

You know... it's not a chemical because it's not "chemically." Stupid poor word choices early in the morning.

[insane_alien]

it is chemically.

 

just because its a common chemical doesn't discount it from the group. a chemical is just something made of atoms, be it an atom on its own or a molecule. water is a molecule. oxygen is a molecule and a chemical. egg white is a mixture of chemicals. everything you can touch is a chemical or mixture of chemicals.

[iNow]

I am very much aware of that. I should have said it differently. I was trying to keep it as simple as possible since the user asking the question appeared not to speak english as a first language, so I "dumbed it down." The problem was, I dumbed it down so much that I made myself look like a dumbass in the process.

 

Thanks for keeping me honest though.

 

So, have you heard about this new dihydrogen monoxide conspiracy where they're adding this chemical to all of our reservoirs, lakes, and products?

.

[vab]

i have a strange feeling that this is possibly to be used for a computer's water cooling system. heck i know something like that would be great to have. but i did a little research and its actually called a bong radiator (funny name i know) but it actually uses quite a bit of water and ice to get the desired effect of spraying it from a nozzle into a much bigger pipe with ice packed around it.

 

the increase in surface area from the smaller particles increase the rate in which it is cooled and also the rate at which it is evaporated.

 

i cant really remember the specs on it but google it and you should find it easily

 

EDIT: Here it is actually, http://en.wikipedia.org/wiki/Bong_cooler

Edited June 10, 2008 by vab
forgot a link >.<