Transfer your nitrous to an aluminum tank and put it in ice is the
cheapest cleanest solution. Those steel tanks suck at heat transfer. You
want to chill it faster/colder use CO2 instead of ice still cheaper than
anything your thinking of.
Cryocoolers are cool but they don't transfer a LOT of heat very fast
pretty damn good but not really GREAT. The cold finger is pretty small
on most of these lower cost units.
They make a lot of liquid helium with these units at CERN.
Sterling engines are pretty cool you can make one and instead of heating
it to make it go. Turn it with a motor and the hot end will get cold
pretty fun!
The cryocollers are really simple just a solenoid between 2 flat springs
really with most of the magic in the heat transfer materials and the
helium gas inside it.
I guess if you got to FAR and started one of the affordable ones up and
got it going used an aluminum bottle and had some great set up for heat
transfer you could cool a K bottle of nitrous in maybe 24 hours. If you
had a special bottle where the cold finger was in contact with the
nitrous you could perhaps make some progress in 4-8 hours. I think I'm
being optimistic.
CO2 would make a great plume and cool an aluminum bottle down in about
30 seconds or so.
CO2 is cheap
Just put the bottle inside a stainless steel curtain with a ring of
nozzles pointing up toward the lower 3rd of the bottle and let er rip.
lol Does not need to be all that tall or whatever.
Just a guess off the top of my head. Sorry for blabbing on about it.
You get it really dense you need to pressurize it and regulate it.
If you asked me it's not rocket science if you don't pressurize it and
regulate it anyway.
-------- Original Message --------
Subject: [AR] Re: Peltier specifications
From: "Mark C Spiegl" <mark.spiegl@xxxxxxxxx>
Date: Mon, August 03, 2015 6:33 pm
To: <arocket@xxxxxxxxxxxxx>
Wow... Im out of the office for a day and my inbox is full! :-)
Anyway.. Anyone who has followed my hybrid projects knows Im a fan of high
density Nitrous. Im looking to cool 20-50 lbs of Nitrous to 25-ish degF.
Goals:
(1) Flashing liquid to vapor to chill Nitrous is fine in a motor burning
10-20 lbs of Nitrous. Much above 20lbs (esp in the desert), flashing liquid
to gas becomes impractical. I would like to start a little closer to my
target temperature of 22 degF. The Peltier, Stirling Cooler, or whatever
would chill the supply tank, not the rocket tank.
I know ice is a quick-and-dirty answer, but I would like something a little
more elegant and deterministic. Bags of ice aren't a great answer at FAR or
Blackrock.
(2) I have had trouble igniting high density Nitrous in warm weather. Cold
weather is no problem. I cannot prove what is happening, but I suspect
temperature gradients in the long thin Nitrous tank are causing the problem.
If the Nitrous is 22 degF at the top of the tank, it may be much much colder
at the injector. Supplying Nitrous close to the final temperature should help
mitigate this problem, if Im correct.
A related question: Any simple ways to equalize temperature between the top
and bottom of the rocket's oxidizer tank???
--MCS
(Im an EE kind of person so my solutions tend to feel like electronics... ie
Peltiers)