Endothermic cooling

Dry ice and Acetone will get you down to -78°C but if you need a little cooler...
Dry ice and Diethyl Ether will get you down to -100°C
after that I thng you need to go down the liquid nitrogen route rather than dry ice.
Acetone is readily available, Diethyl Ether not so readily available to the public.
#would -78°C be cool enough? if so go for the dry ice and acetoneUsed it a lot when I was a yoof.

Dry ice. A bit to cool, and not easy to come by in a local shop
 
Exactly.



I wonder if the OP is actually more interested in cooling something down for a short while rather than keeping stuff cold in a fridge for hours or days.

e.g. Sitting in the baking sun with warm beer and no ice on the boat, just warm water and "magic powder" sitting at ambient temperature..

Yo. You're getting the idea. No fridge, the ice is long melted, at anchor, the sun is out.... ..... Just wanna cool a beer, or chill the the cold box to keep food fresh a bit longer. No -70 degrees man, just chill it Must be food safe, safe to carry aboard, legal, and easily available when in port. No urea, no poisons, just safe easy coolin man. And not damaging to the earth, sea, wildlife I'm out there to enjoy.

Come on forumites, you can do better with ths science project I know....
 
Probably better to describe them as endothermic processes rather than reactions

Nothing involving liquid nitrogen, dry ice or even ordinary ice is of any interest. If the OP could store or even obtain them he'd have no problems anyway. He could just stick his cans of beer in a box with one of them.

What he wants is a couple of common substances , that are easy to obtain, can be stored without requiring refrigeration themselves, are safe to handle and when mixed will undergo a endothermic chemical reaction.

Since posting I have tried my suggestion in #2. It works but the amount of heat absorbed is not very great and the result, although interesting, is unspectacular.

I'm reading with interest. Come on, come on, solve this one and leisure sailing a small boat gets even better
 
Fair enough. I still think a cooling box at -5°C could be more useful than +3°C (and ice should be available at any port) but you do have a point. I'd be genuinely interested in a recipe not requiring ice or cooled water however.

Yes yes, no ice aboard, that's why I need cooling!
 
I seem to recall from school that sherbet creation is endothermic so you could keep the ingredients for that on board and make sherbet when you need a cold beer :D

Ok worth a try. And the ingredients are?....

They are citric acid and sodium bicarb which as Nigelmercier has pointed out are the common names for the two compounds I mentioned in post#2.

Safe, easy to store and readily available but not all that effective but maybe worth a little more consideration and a trial or two

Ammonium thiocyanate and barium hydroxide I believe would be more effective.
I doubt if so readily available especially barium hydroxde which is both toxic and caustic.
Ammonium thiocyanate is hygroscopic. Barium hydroxide will absorb carbon dioxide from the atmosphere so both would need careful storage.
 
Ammonium nitrate and water? Commonly used in instant cold packs. Ammonium nitrate is pretty harmless stuff, although it does have ... explosive possibilities in combination.
I didn't know that, but I looked it up on Wikipedia http://en.wikipedia.org/wiki/Instant_cold_pack. The bonus is that it can be extracted from the urine after drinking beer, making the beer cooling process self-sustaining :)
 
Yes of course, but they are too hungry for power. No good in a peaceful anchorage without running the engine, or a generator which I don't have on a small sailing boat

If you don't want noise, and you don't want to be trucking around kilos of toxic chemicals, why not try some clever physics instead of old-school chemistry?
The Peltier Effect (thermoelectric cooling or heating) has been well-known for donkeys, but until very recently, the cost was prohibitive. But now the costs have plumetted. For example, a 100W unit on Amazon UK for just £6.99

e.g. http://www.amazon.co.uk/100W-TEC-Thermoelectric-Cooler-Peltier/dp/B007TPCEKI

Stick that in your cooler box, with a 100W solar panel to provide the power, and you have one effective solution. UK weather permitting, your mileage may vary.
 
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If you don't want noise, and you don't want to be trucking around kilos of toxic chemicals, why not try some clever physics instead of old-school chemistry?
The Peltier Effect (thermoelectric cooling or heating) has been well-known for donkeys, but until very recently, the cost was prohibitive. But now the costs have plumetted. For example, a 100W unit on Amazon UK for just £6.99

e.g. http://www.amazon.co.uk/100W-TEC-Thermoelectric-Cooler-Peltier/dp/B007TPCEKI

Stick that in your cooler box, with a 100W solar panel to provide the power, and you have one effective solution. UK weather permitting, your mileage may vary.

Peltier effect........ as discussed in the OP's previous thread before he started this one.
http://www.ybw.com/forums/showthread.php?369134-Cool-boxes

:)
 
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I guess this thread started as a result of my posting on the "Cool Boxes" thread.

The instant ice packs which are now available for First Aid seem to be much smaller than those I used 30 odd years ago. Also they only stay cold for about 20 - 40 minutes.

Unfortunately, I can't remember the name of the packs but I think I would have got them in a camping shop. IIRC the bag was the size of a piece of A5 paper and I must have used a couple of dozen of them over time.

Paul
 
If you don't want noise, and you don't want to be trucking around kilos of toxic chemicals, why not try some clever physics instead of old-school chemistry?
The Peltier Effect (thermoelectric cooling or heating) has been well-known for donkeys, but until very recently, the cost was prohibitive. But now the costs have plumetted. For example, a 100W unit on Amazon UK for just £6.99

e.g. http://www.amazon.co.uk/100W-TEC-Thermoelectric-Cooler-Peltier/dp/B007TPCEKI

Stick that in your cooler box, with a 100W solar panel to provide the power, and you have one effective solution. UK weather permitting, your mileage may vary.

Now this is the best suggestion so far on both this and the cool box threads. So a cool box with a pelt ire cooler powered by a solar panel. Kept in the cockpit, when the sun shines I'd get maximum cooling. Perfect except for the cost of the solar panel, a heat sink, fan etc.
 
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