Hyperspace Pirate - 2022-12-07
In this video i expand on the resonant linear motor from my previous video and use it to drive a linear compressor for a pulse-tube refrigerator. A pulse tube refrigerator is used to reach cryogenic temperatures, with some going into the sub-kelvin temperature range. These are typically used in labs for scientific experiments that require extreme low temperatures, or for sensors on sattelites/spacecraft, like the optics on the James Webb Space Telescope. From a thermodynamic standpoint, a pulse tube cryocooler is effectively the same as a Stirling or Gifford-McMahon (GM) cooling cycle, but it replaces the displacer (or expander piston in the case of an alpha-stirling) with a gas piston. With careful tuning of a needle valve, inertance tube (gas momentum tube), and buffer volume, the phase of the gas piston's motion is shifted from the pressure oscillations of the compressor (by ~60-90 degrees), allowing heat pumping to occur out of the cold end. The major advantage of this device is that it eliminates moving parts from the cold end, which would be the displacer piston in the case of a Stirling or GM cooling cycle. While i did manage to create a working linear compressor with a tuned dynamic balancer to create pressure oscillations, the linear motor didn't seem to have enough force to create a reasonably large compression ratio, and i only managed to produce a minor temperature difference. However, actuating the piston by hand, i was able to produce a temperature drop of around 4C. Pulse tubes are also extremely dependent on the tuning of the needle valve, inertance tube, and buffer volume, which act like an electrical RLC circuit to create a specific phase shift at a specific frequency. The pneumatic tuning in this video was far from optimal. In the next part of this series, i'll be replacing the linear compressor with a rotary compressor that I plan to build with an air cylinder driven by a geared down brushless motor from an RC plane. I'll also be focusing heavily on tuning the inertance tube / buffer volume, and optimizing heat exchangers to remove energy from the system even at small temperature differentials. Previous video on building a linear motor: https://www.youtube.com/watch?v=u7k2wiY4Flo&t=11s If you want to understand the basics of different cryocooler types, these articles are helpful: https://www2.jpl.nasa.gov/adv_tech/coolers/Cool_ppr/CEC2005%2050yr%20History%20of%20Cryo%20in%20Space.pdf https://www2.jpl.nasa.gov/adv_tech/coolers/Cool_ppr/Chap%206-Refrig%20Sys%20for%20Achiev%20Cryo%20Temps_2016.pdf This is a helpful overview of how different pulse tube configurations work: http://large.stanford.edu/courses/2007/ph210/bert2/ This paper explains more about the math in computing resistance/inertance/compliance and phase shift: https://trc.nist.gov/cryogenics/Papers/Pulse_Tube_Cryocoolers/2006-Inertance_Tube_Optimization.pdf Another resource i found tremendously useful was https://cryocooler.org/. Under "Past Proceedings - Volumes 14 to 20" you can select a volume and under "Table of Contents" there's dozens of research papers on Stirling/GM/Pulse Tube cryocooler development. STL Files (these are for the linear compressor with the TPU bellows piston): https://www.thingiverse.com/thing:5684574 Music Used: Heatley Bros - Sunset Beach Kevin MacLeod - George Street Shuffle Kevin MacLeod - Lobby Time
if this contraption could talk, i think its 1st word would be "giggity"
lmfao
The only joke like this here, everyone else (including me) is a fuckin nerd. Go science.
HahahHa😂
definitely haha 😂
this could be developed further to become the most popular toy for M and F
WTF!😂
People have been doing this kind of thing in their garages for decades (popular mechanics had a legitimate set of plans for a build it at home electron microscope back in the day) but youtube has enabled unprecedented levels of sharing for which I am eternally grateful.
This is that STEM education we always wanted. Ties in so many field together. Makes me want to rise up to your level. Thank you so much good sir wherever you are <3
I recognized the Stirling cycle, the adiabatic etc. etc. from my HS physics course. It took me weeks to get my head around it, and this video probably would do it in, well, 18 minutes :D
bling bling, that stem a char lmao! He wants us to believe that he is building a pulse tube cryocooler, but what he is really doing is solving that huge problem, the problem of a dead lighter. lmao
This is absolutely fascinating. This video far exceed my expectations. Your explanations and graphics made the concept really clear.
And the audio quality is great even monotone. The script isn't amzzing but not terrible, the odd breakand deceny story line.
After 30 seconds of watching I was subscribed
Great stuff
it's cool
Thanks for saying this; saved my thinking out the same :D -Good work
Hey I actually just started at a company that makes Gifford McMahon coolers! I think you understand this a lot better than I do, but if you have any questions, I am surrounded by experts on the topic and would be happy to ask them for you. Keep up the good work!
Good luck with your goals! I have big 0.7W 4K cooler from MRI machine, but only 1kW He compressor. Question to answer would be if there is any chance to make big cooler functional with much smaller compressor, given that I can accept much lower heat lift capacity, but keep low temperature at very light load.
@@xDevscom_EE It is possible to use a smaller compressor with a larger cooler, but the cooling capacity of the system will be reduced, meaning that it will take longer to cool down and will not be able to handle as much heat. The ability to maintain a low temperature at light loads will depend on the specific requirements of your cooling application and the thermal properties of the materials being cooled.
@@GudLawdHammercylonger cooldown time is expected, as well as limited capacity. It is just temperature that I am after. I haven't find any research papers or reports yet showing performance limits of such system, with large (>0.5W @ 4K, like PT407) head used with small compressor (1-2kW power in) and concerned if heat loss and mass flow required for large head make this unworkable. I guess I should just try to run it and see what happens...
The theory and the scientific facts behind the mechanism are well explained. You started with a great design and you iterated it to better forms by using feedbacks and new ideas. The balance between the theory and the building process is right on the optimal point.
I already knew something about ultrasonic cooling/heating but the concepts in your video (vibration cancelling/phase shifting etc) are really new for me and there are really cool concepts.
And there will be a really cool end result which you can use it for doing real science. I mean, liquidifying the nitrogen is a real deal.
So, in conclusion, i really appreciate your work. This project and the presentaion are beyond my expectation from internet. I honestly wanted to thank you.
most importantly, you didn't give up! as Edison once said "you didn't fail a bunch of times - you successfully found a bunch of ways that didn't work!"
The lack of snicker shame in this video is upsetting.
Great video and interesting project. Can't wait to see more and be shamed for it.
I don't think I've subbed anything as hard as I just have right now. Incredible work!
Really neat, and props to you for posting the project and all that, even if it wasn’t 100% successful. Even though it may not get all those views and whatnot, documenting the full development process and all that failures/things learned along the way is important and neat!
I knew something like this had to be coming when you mentioned the vibration stabilizers. Cold finger FTW
I understand hardly anything, but I love it ❤
I was telling a colleague yesterday how I'd always wanted to build a cryocooler so super happy to see this project. Subscribed. Fascinating. Hot is easy, cold is such an unexplored world. Inspiring.
That’s really cool, several years ago I saw a clip on TV that was highlighting a refrigeration system that didn’t use refrigerant running freezers in an ice cream shop - it must have been related to this design because it used very powerful speakers enclosed in a tube that was able to pump heat, didn’t give much detail but I remember being quite inspired by the innovation.
- Accoustic refrigeration -
air is the refrigerant.
Very cool project! If I could make a suggestion or two: that resonant balancer is neat but super lossy. It'll be sapping a lot of your energy. The simplest and least interesting solution is to bolt the entire device to a heavy metal base, but there are also better and more interesting solutions. You could swap your moving mass with your static mass - a fixed magnet and moving coil (essentially a voice coil) using aluminium wire wound on a former would be much lower mass. Or you could use two motors diametrically opposed and in phase to cancel out the vibration - you'd need to match their resonant frequencies. Finally you could use two motors 180° out of phase and a manifold to couple the gas - the same resonant frequency matching would apply but note that some torsional forces be present somewhere between the two motors causing some vibration. I hope this was helpful in some way and can 't wait to see where this little project goes!
Your videos make my day! Thank you for providing us with this quality engineering content
Absolutely awesome. I looked into these coolers a bit and am intrigued to build one. Looking forward to part 2!
This is impressive. Great work. The balancer is genius.
Блин, открытие века )))))) Такая хрень использовалась для подкачки воздуха в аквариумах ,уже лет сто .
Hopped on youtube to take a quick break from studying for my Thermodynamics class and ended up clicking on this video lol... Feel like I am still studying, but enjoyed it immensely more. Thanks!
Absolutely brilliant work! Well done! Relating cooler parts to inductors, resistors, and capacitors is interesting.
Best explanation of the Stirling cycle I've seen anywhere.
This is so cool! 🥶
Never heard of these devices before and still trying to wrap my head around it. Thanks for the explanations, looking forward to many more parts!
It was fun to see your linear motor's, the mass dumper's and camera shutter's speeds all sync up.
Very cool. Was interesting to see the device translating across the desk. Reminded me of a space propulsion concept which inchworms it's way through space by shoving a mass forward, and then the rest of the ship moves forward. Frankly, I didn't thing that could work, until I saw your cooling device moving along.
if only these tools were available when I was in grad school! Your engineering/thermodynamics skills are amazing! Thanks for sharing this. Doug
Fascinating video! I just finished a circuit theory course in college so i absolutely love the comparisons of the various parts to electric components. Helped me understand so much more how everything worked.
This is the greatest home-engineering thermodynamics related video I've ever seen!
This is what youtube is all about. Super smart people making stuff that they find extremely interesting. this is some Newton and Einstein stuff right here. never stopping for obstacles
One of the most amazing and informative video in the history of the YouTube. Please continue!!
This video really excited me, I’ve been looking for a used cryocooler for ages but they’re not easy to find cheaply in Australia. You’ve given me hope that they may actually be able to be built by amateurs !
IMHO - The biggest thing most people take for granted in life is our ability to control and manipulate heat and cold exchange. If we can learn how to heat and cool things more productively with less energy requirements for our homes - that imho would be the next great tech step. Imagine all our AC units being replaced by more efficient coolers. Whoever does that will be the next big money maker. Just make sure you get those patents covered :) Who said re-inventing the wheel is a bad thing? I look forward and will keep a very focused eye on your work. Thanks for the uploads.
Great project and awesome presentation, more intuitive than my thermodynamics professor at university!
I'm a moron, but this was a great video because it actually improved my understanding of things even though those things are still way over my head. The video is also very well produced. Your choice of music bedding did not interfere with your words and you set the volume of it almost perfectly. Your images were clear and stable. If I was a professor I would give you an A+.
be Free
🏃🍎,?🪤🎯🔥
This is a superb work of engineering, your work is inspiring
It has been a long while since I saw and deeply enjoyed a video last time. Man, you take me all the way back to school. I like it a lot.
I just discovered you today and I'd enjoy using one or two of the items you've made. I have an idea that might be beneficial for not only us but the world as a whole.
Brilliant video especially with the electronic analogies
i never eim amazed
Simply amazed by how incredible your work already is and the explanations that are actually understandable !
WOW! Give an engineer a 3d printer and see what he does with it!!1 What? No useless boaty prints! I loved learning about this design from this video.
I have no idea what's going on, but I am here for it!
my wife left me after making one of these she said she doesn't need me anymore, thanks bro!
First time watching and wow.. I am just so impressed. Everything was explained fully including the math behind it and your thought processes are fun to follow. Keep up the good work!
Great effort on this attempt, you are really making me feel like I need to use my 3d printer more.
So I used to work in a thin passive component fab and we used cryopumps on almost everything that didn't involve Silane(a super scary gas). A cryopump is just a cryocooler with basically a heat sink on the cold end that gas would freeze to and pump out the cavity. I think we had around 30 cryopumps and would re-build a couple a year. They were all of the Stirling style where the regenerator was stacked mesh in the displacer. They all had large compressors and used a valve cycle style setup.
Typically our pumps would run somewhere around 8-12 Kelvins(when they were at running well).
Once I got to look inside one when it running and had the baffles off; the frozen gas on the carbon heat sink looked just like water frost might look even though it was just frozen air at 10s of Kelvins.
Channels like this is why the average youtube session lasts many hours....bravo you got my subscription :)
It's funny how with enough insight and ingenuity, even things like cryocoolers or EM resonant oscillators can be built using 3D printed parts and hobby-grade electronics. Is it as effective as something like a professional cryocooler - probably not, but the fact that it could be close with enough time and tuning is amazing to see. Gonna have to keep my eye on this project!
Really nice projects ! Thank you for your hard work and dedication !
Thank you for the parallel circuit explanations. I have been thinking about materials science this way for years and no one seems to get it. The universe is electric. Everything is a circuit. This also explained how part of my fusion reactor design works, through absorption.
This is so cool! I have always wanted to build a LN generator. I'm glad I found this channel
I can't wait for part 2. Fascinating!
@HyperspacePirate - 2022-12-20
BTW, "Sub-kelvin" isn't referring to below absolute zero (which is impossible), it refers to temperatures that are between 0 - 0.9999..... kelvin
@friedtomatoes4946 - 2022-12-20
Something to consider is that even fully filled 3D printed parts can leak air. You may want to go onto your compressor parts and cover them in some form of sealant. To test this take one of your 3D printed parts and make like a box with a clear side and then put it in water at a certain depth if it starts to leak then you've got leaky prints.
I recommend silicon and epoxy
@Marin3r101 - 2022-12-23
Hmms so you mean a 1 is a singular value and thusly could be dropped entirely resulting in sub-kelvin?
@horrorhotel1999 - 2022-12-30
Just for completeness sake: negative absolute temperatures i.e. temperatures "below" 0K are in fact possible but these are incredibly energetic systems and can only be achieved under very specific circumstances.
A fun rabbithole to go down nonetheless if this interests you.
@jonathany1240 - 2023-01-03
yeah i was curious about this - whoever came up with the term "sub-kelvin" gets a pass on using counter-intuitive language bc it sounds cool as hell
@wolfy1398 - 2023-01-04
@@horrorhotel1999 Can you link something to read more about this? I'm really interested.