Making Liquid Nitrogen with my Homemade Cryocooler

Hyperspace Pirate
Hyperspace Pirate
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2024-07-15に共有
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In this video, I'll show how I built a cryocooler out of salvaged air conditioner parts that's able to make liquid nitrogen at -196C.

The system operates on a process known as the Mixed-Gas Joule Thomson cycle. A mixture of refrigerant gases are compressed, cooled to ambient temperature, and then expanded inside a long counterflow heat exchanger. When the gases expand, they cool. Cold, low-pressure gas cools the incoming high-pressure gas causing it to drop its temperature even further, creating a snowball effect that drives the cycle down to cryogenic temperatures. The lowest temperature I've achieved is -180C with a 30/70 mixture of Propane and Argon.

For higher performance, a separate vapor compression system is used to pre-cool the gas mixture to around -30C before it enters the regenerative heat exchanger. This adds complexity, but nets a performance gain, since total cooling power goes up by 30-50% with only a 15-20% increase in energy consumption.

The super cold gas travels through a heat exchanger pipe in a small tank. High pressure nitrogen is pumped into the tank at up to 30 bar and liquefies at around -150C. Once the tank is filled with liquid nitrogen, it's discharged through an electronic expansion valve at the bottom of the tank into a thermos or dewar.

This is different from the pure-gas joule thomson cycle in which nitrogen is expanded from 200-300 bar to atmospheric pressure to create a cooling effect. In the mixed-gas cycle, the refrigerant gases and the process gases being liquefied are two different streams.

The gas mixture being used is:
25% Propane
15% Ethylene
20% Methane
20% Argon
20% Nitrogen

The typical operating pressure is 400 psiG on the high pressure side and about 20 psiG on the low pressure side. Power consumption is approximately 1.4 kW, and my current production rate is about 130cc/hour of liquid nitrogen, though I'm confident this can be improved close to 300cc/hour with some adjustments. The current energy cost is about $1.29 per liter produced.

For this video I've used nitrogen gas from a tank I purchased, but in a future video I'll show the process of separating out oxygen/nitrogen.

Music Used:

Kevin MacLeod - Groove Groove
Kevin MacLeod - George Street Shuffle
コメント (21)
  • @AppliedScience
    Nice work! I've enjoyed following your progress, and it's great to see liquid nitrogen made with everyday parts. I haven't seen anyone else make ln2 with air conditioning compressors. What a journey!
  • @wojciechdebowski5014
    Hyperspace Pirate: complains about his methane tank exploding Also Hyperspace Pirate 5 seconds later: Shows us a very competently designed pipe bomb disguised as heat exchanger
  • @SkylerLinux
    Watching your videos really makes me want to make a compressor cooling system for my PC
  • @ThePowerofElectricity
    The reason you lost your rotary compressor despite the cooling was indeed an oiling issue. While the piston compressors like the fridge transfer one have their oil sump in the low pressure housing and actively use a small centrifugal pump to lube themselves up, the bigger rotary ones have their oil sump on the high pressure side. That means in order to avoid efficiency loss, they can't simply allow the oil to bypass back into the rotary set and instead rely on oil making it all the way trough the loop and back into the suction side. If there is no oil in the gas that comes from the suction, they have no lubrication at all. A fix would be another oil separator loop for the nitrogen comp. Even while the fridge transfer compressor might work, you're still loosing oil out of it slowly, so with enough time and no refill it will die too. Not to mention that some oil might get all the way into the cryo chamber and freeze up in there.
  • @maximus_stp
    I always wondered why old AC units always came with that extra part in the bottom left 0:23, glad it wasn’t just me who noticed.
  • @Seb_292
    11:58 That equation brings me right back to my first semester of electrical engineering :D The TCR of copper will stick with me for the rest of my life
  • @janoutuber1069
    Literally watched like 5 of your vids today, they're masterpieces, the memes, the chemistry, the animations and engineering. This is my 1% top channel on here
  • @thesentientneuron6550
    You have no idea how much glee this video brought to me! It feels like somewhere in the back of my mind an unknown challenge had been conquered…or I suck at thermodynamics. Probably both . Anyway, crazy cool stuff, fridge pirate! Need that cryo pod for hyperspace travels, right? Perfectly understandable and a valuable resource for fellow pioneers. We do appreciate your contribution.
  • @Nobe_Oddy
    This HONESTLY has been one AWESOME JOURNEY!!!! I have learned SO MUCH from watching your videos from the beginning (well, the beginning of this journey to make LN2) - I probably don't and won't retain much of it, but I LOVE learning about new things that are so far removed from my typical realm (computers are MY thang) But YOU made this journey frikkin HILARIOUSLY ENJOYABLE and I JUST CAN'T WAIT to see what you come up with next!!! - Thank YOU for EVERYTHIGN Hyperspace Pirate... YOU ROCK!!!!
  • @-r-495
    „what are you doing?“ „cryo-cleaning the garage, honey!“ Well done!
  • @DreadX10
    This is the reason a word like "Wow" was invented. You not only did it; you did it well and we all know how well because you were so kind enough to take us with you every step (and step back) of the way!
  • @paranoiia8
    Damn I love that series 😅 only here we have pretty advanced diy cooling methods with 1000 versions of tubes and tanks... But no button to open a valve 😅