I've read through the comments and thought I'd address a few of them: -The 40mm piston is probably not optimally matched to the pulse tube geometry, since i optimized it for higher frequencies on the 25mm piston -For part 3 or 4 i'll probably try using Hydrogen as a working gas. It has a lower specific heat ratio than helium, but the highest thermal conductivity of any gas, so I should see an increase in performance as long as all the components are sealed well enough to avoid leakage -For part 3 I'll be looking at heat exchangers with multiple heat pipes and water cooling, as well as single tubes packed with copper wool. -I do intend to evaluate a segmented regenerator with polymer "heat breaks" to slow down axial conduction losses by breaking the continuity of the metal mesh -For higher pressures and lower temperatures, I'll be replacing the PVC with stainless steel to avoid explosion hazards. -The ESC has flyback diodes across the H-bridge MOSFETs, so any back-current from the flywheel after motor shutoff should be dissipated through those. -Multiple stages might be neccesary to reach LN2 temperatures with a DIY setup. Pulse tubes can be staged by connecting a much smaller pulse tube to the output of the compressor's aftercooler and thermally anchoring the second heat exchanger to the cold end of the first stage. Pulse tubes used for liquefying helium/hydrogen typically have 3 or 4 of these stages and can reach single-digit kelvin temperatures

@Axman6

Жыл бұрын

I’d be really interested to see more tests with increasing the regenerator diameter so the gas flowing over the steel wool is moving at a slower velocity; if your idea about the velocity of the air getting too high is right this should help… maybe 🙃

@BirdbrainEngineer

Жыл бұрын

- Hydrogen is incredibly difficult to keep sealed; just look at the troubles and delays with SLS - I wouldn't be so sure that you can use water cooling... wouldn't the heat exchanger itself not get cold enough at one point to freeze water inside the heat exchanger? Then you have an insulator in the pipes instead!

@marttileppanen

Жыл бұрын

Could you add a new stage just by eg. adding a Peltier element (with a heat sink) to forcibly cool down the hot end and thus increasing the temperature difference? They're not terribly efficient, but can move tens of watts of heat without using moving parts?

@vladovrhovsek

Жыл бұрын

You should ISOLATE ALL around the precision valve and after on the right, all the way to coper pipe and reservoar. When air from the resevoar expands through valve, it cools off, and it is good, that it is cool as posible, before expands.

@WetDoggo

Жыл бұрын

is the volume really really low or what?

This is by far, the most interesting video project recommended by KZread in a long time. Great explanation and accurate presentation. Amazing work, keep up the good work. Hope to see -200C in a while :)

@drezster

Жыл бұрын

I second that. Looking forward to some liquid nitrogen in the near future :)

@pradipda3171

Жыл бұрын

So True otherwise youtube only promotes garbage and clickbait

@xmysef4920

Жыл бұрын

Gotta agree with ya!

@jtjames79

Жыл бұрын

I agree this is highly relevant to my interests. I've been wanting to test out instead of using heat to evaporate water from my 3D printer filament, sublimate it with cold instead. Freeze drying machines are ridiculously expensive. I could do so much science with this!

@fickgooglefickthem6884

Жыл бұрын

In case You don't know: watch the "star in a jar" project by the plasma channel. Just a recommendation

This is fascinating. The first DIY cryocooler that works sufficiently This is the first DIY project reaching really low temperatures without complicated multistage refrigerant stages.

@AttilaBlade

Жыл бұрын

:) Not the first that works well, but with a really cool presentation!

That's some seriously impressive data analysis and scientific method for a simple prototype! Great work - subscribed!

@Stoneman06660

Жыл бұрын

Yeah, couldn't agree more. Often that sort of info is missed during YT content which I assume is to make it palatable to a wider audience who just want to see stuff built, tested, and completed. (Or blow up; intentionally or otherwise).

When cleaning wire wool up wrap the magnet in a rag so you can separate the captured steel wool from the magnet to dispose. Great to see an explanation of why gas-gas heat exchangers are hard to design!

@maqabayker

Жыл бұрын

Gas-to-gas heat exchangers are much harder than the other because overall heat transfer coefficient is substantially low that you need very large equipment for that. Because of that, the diameter and length of the heat exchanger gets larger and larger. If you intend to do gas to liquid heat exchanger, it is far worse than it seems, because the liquid will have higher conductivity while gas will have very low conductivity which makes a lot of problems on the design process. Other than this, the pressure drop across the heat exchanger will be very high for gas effluent (because of high velocities) depending on what type of heat exchanger and which side you intend to have liquid flowing (if it is shell and tube heat exchanger of course) In my process design course, I had a lot of problems with superheated vapor stream and it was a nightmare to get the correct design values.

@kitemanmusic

Жыл бұрын

Great suggestion. Could use a vacuum cleaner or a small brush.

@mrf4549

Жыл бұрын

Instead of a rag you can also use a sandwich bag but the rag works well too.

this is incredible you are the only youtuber that shows how to make a cryocooler keep this up

This is the best thing that KZread has sent my way in a LONG time. Thank you so much for the amazingly well made video, and I can't wait for the next part!

The clarity & detail in your explanations is absolutely amazing, the collected data and visualizations really help to make this more intuitive. You're a great teacher!

Love this series, seriously. I feel like I understand now how “real” engineering is done. Keep the videos coming!

This is super cool, I went down a rabbit hole of research into cryocoolers about 6 months ago but never found anyone else doing it DIY. I'm glad you took it to the next step and built it!

I just want to say that in terms of video produciton, you've done an excellent job in the treatment of the calculations and design considerations. You've somehow kept your explanations concise without glossing over anything big, and made it accessible without dumbing it down. Your channel is the best one KZread has recommended me in a long time.

The use of the scaling exponents to predict the behaviour, along with the brute force empirical parameter sweep was beautiful ❤️ I wanted to click like so many times in this video but sadly I am limited to just one. This is so beautiful.

Awesome video. I have been intrigued by pulse tube coolers since I heard about it on JWST, so to see a functional DIY build is astounding. Great work, looking forward to part 3!

Fantastic progress!!! I admire your bravery to take on such a challenging problem. Can't wait for part 3. Thank you so much! 😘

I more or less stumbled by accident over your videos, but the subject is very fascinating and they are one of the best youtube videos I ever saw up to now that combine practical use with scientific background. Wish my scool lessons in physics or thermodynamic would have been so interesting! As already said by others, you would be a very good teacher! Many greetings from Germany and all the best for upcoming 2023! 😃

This is excellent! Having scratch-built several high temperature Stirling engines, I very much appreciate your approach to this.

@mikeconnery4652

Жыл бұрын

Were you thinking of using the waste heat. Also, would a sterling engine make a good power source on the moon?

So, I don't comment often, but you are fantastic. This is such a great example of scientific and data driven innovation. Finding ways to isolate, measure and iterate individual components is the name of the game, and you have done it wonderfully.

I love how far diy projects have come since the early days of KZread a decade ago which were 90% LED projects keep up the good work

What a magnificent video. I love how well you are keeping track of all the variables and then plotting them on a graph, it's a very nice tool to have when trying to optimize such a system. Well done.

Your channel is a goldmine for us mechanical engineering students. Thank you for the detailed content!

The explanations, calculations, and even concept presentation in this video is top notch. I’m learning and enjoying it

You're perseverance is the spirit of the scientific method and it gets you results. As a result This is SOOO damn inspiring

Man, I loved the last video and this one didn't disappoint. Great job I'll be watching for updates.

That I could understand this using memories of high school physics from the distant past speaks volumes for your presentation skills. The KZread recommendation engine has a success for once. Excellent video.

Well I must say, this is my new favorite channel. I love the inclusion of the formulas. Thanks!

That was one of the most interesting videos I have seen in a long time. I semi-learnt a ton of things from it. I say "semi" because there was stuff in it that I didn't know I didn't know. So I didn't exactly "learn" but now I know where to start in truly understanding some of the science and engineering behind the fluid and thermo dynamics of this. Thank you, I've subscribed and look forward to the next part.

This id one of the best documented experiment with best scientific illustration, salutes

Once you can turn air to liquid i know this channel is gonna blow up. Great editing, the graphs are sweet. I'm getting ready to follow along.

I have to say your logic in doing this project is right on. Have to admit you and I are brothers from the same mother. Look forward to your videos that take my imagination of making things to another level for sure. Keep up the great work fella.

Truly remarkable in my whole life as an engineer to this date it's the first time I realised how difficult it is to build something when you are dealing with multiple variables

Wicked work and for how much information you put across it doesn't get dull. Looking forward to future updates :)

Very impressive! It's clear you put a ton of effort into both the project itself and the video. Thanks for sharing!

I think you just gave me an idea to rescue my old GM-Cryo system... Great video, excited to see where your journey will continue to go!

I have a ton of these types of components laying around, I have doubts I will ever get around to actually doing this but this is extremely cool. You have my respect and you have my subscription.

This is the best fluid dynamics lesson I've ever had

Just found this channel via KZread recommendations, and I must say, I am thoroughly enjoying it. Subscribed.

I really think adding the second piston will yield better results! Can't wait to see the next video on this!!

Bravo! Looking at your channel - all the videos you have made - you should have at least a few million followers! You indeed, are one of the few.

Excited to the new episode! Pretty interesting to see that actually cooling Oxigen and Argon.

Really excited to see such great results! I definitely plan on building one for myself in the future

@vincentli9106

Жыл бұрын

if you do it, for the love of God tell me how you did it. I can't build crap!

@b-beluga4510

Жыл бұрын

@@vincentli9106 sit in toilet bruh

data analysis and scientific method is unbeliavable. Thanks a lot for sharing!

Can't wait to see the sequel! Captivating work i love it!

This is amazingly thorough and well thought out. Congrats on the Hackaday link too.

This is the 'coolest' thing I'll see today on KZread. Thanks for sharing.

Great idea! The functional part of “cold effect” you’re using is the guarantee of all potential energy lost in a cold stuff. To amplify your effect discover ways of reducing potential energy in the material used. Specific heat is one, or the ability of a material to regain heat. Isolate the chamber in all directions except one (or so) and draw it through a salt-water bath, which is notoriously disconductive of heat. Hope to see Part 3!

One of the most underrated channels on KZread

Great video, love the way you document every step and show your working. 😊

You could try to improve regenerator performance by using several "sub-regenerators" to prevent heat conduction axially. In practice, instead of making one blob of steel wool, make several and stack them inside the tube.

@mitchellstrobbe7779

Жыл бұрын

I wonder if adding an insulator material or air gap between them would help as well

@TopiasKorpiTK

Жыл бұрын

@@mitchellstrobbe7779 What I've read, having an air gap or insulator material between sub-regenerators does not improve the perfomance much at all. Axial discontinuity in the regenerator should be enough to prevent axial conduction.

@kreynolds1123

Жыл бұрын

Try a stack of stainless steel filter mesh. Not only does stainless steel have a much lower thermal conductivity than the steel in steel wool, but heat has to flow laterally along the before reaching a contact point where it can flow axially to the next screen. The second part contrast with the random orientations allowing comparitivly faster axial heat conduction with steel wool.

Really excellent presentation. I’m looking forward to seeing more of your work! Success or failure, both will be a fascinating learning experience.

I love your content, it is a beautiful example for everything engineering stands for, thank you for producing it.

Dang it, i cant wait for the next one, these are so cool and i really enjoying seeing what you build and your thought process, cant wait to see you get some liquids dropping out of that baby, cheers

Great work!! Very exciting performance for very modest materials, I'm really looking forward to your next video.

Can't wait for the next video! Very nice job!

4:00 this is a very well done explaination for a really complex system that throws numbers and formula symbols at you like a gatling.

I love the intelligent and thoughtful community you've fostered, I scroll down and all I see is intelligent and thoughtful comments instead of my first instinct which was laughing at the robo pubes at 8:45

This is a super fun project to follow, thanks for the thorough presentation!

Man that's cool! I'm hooked. Can't wait for the next installment.

I wish my professors were as good as you and your explanation. VERY WELL DONE

Man, refrigeration is such a cool topic. Thank you for this video.

Very cool video. I liked how you showed the math and explained the relations between things such as the effect of the diameter of the copper or the differences in surface area used in the regenerator. You got my sub

I was kind of getting board of all the math then... "my homemade CNC Mill"! I was instantly paying 100% attention. Great Video Man!

This is kind of a project I would have expected to see from Ben / Applied Science! Really cool, great job!

Really loving these videos. Great work and learning a lot.

It was a great presentation again! Congratulation! DELTA EC program from Penn State University could help a lot to you in the next steps. There is possible variations of heat engines and heat pumps from simple alpha Stirling to pulse tube via thermoacoustics. The resonant frequency of the system is one of the main thing to increase the performance with a better performance of HX & regenerator also with changed basic parameters. Try to abstract from the pressure ratio a bit, because ThermoAcoustic systems could rich this temperature range easily with low compression ratio, typically under 10%. These materials that you used are enough good for a trial run where you can see the effect basically, but with this density, wire diameter and thermal properties of the regenerator just with a bit poor performance. The Achilles-heel the HX parts in every "homemade" heat pump. (I think it again, because maybe just we've made this type of unit in public...) I know you've learnt a lot about this unit, I'm impressed!, so I just suggest to you look around the thermal penetration depth for better performance of heat exchangers. The regenerator density is not a big problem here, that will create a phase shift too, when it will dense enough so try to not worry about it too much. The moisture is a real problem, because the ice could block the gaps. Alpha Stirling has a high compression ratio but if you can hit the -100 degrees Celsius you will experience strange things with sealing, or around the solid material when you want to going under. BLADE SPS: Sorry for the essay!

@Al5052H32

Жыл бұрын

Would a phasor diagram be of help here? I have been led to assume that mass flow is king. Edit: also that the goal of a phasor diagram is to balance the diagram on the middle of the regenerator. Would this be correct?

@mikeconnery4652

Жыл бұрын

Thank you for the essay

Brother what the hell did you study to all know all this, not only physics but your grasp on electricity is also astonishing, keep making videos love this stuff

This is so cool! Please keep going! I really like the optimizing approach you took :D

A very thorough video. Made me think of poteen making.

Amazing piece of work. Really impressed!

Really enjoyed watching you experiment with the cooler, cant wait to see how it goes in the future so i subscribed.

This project is as mental, as impressive. I love it

I don’t understand much of it, but I can appreciate and enjoy it, thanks man

Thanks for your videos! I really enjoy them.

Soo cool! Pun totally intended! One of the greatest videos I've seen for a long while. Keep it up. Please 🙏

Im glad I found your channel. So cool!

Love these beginner videos. Thank you.🥸

Cant wait to see part 3, great stuff

amazing video thanks. i study engineering and watching this video was way more clear then many labs experiences in my uni

very cool... I'm after the same thing but ur way smarter than I! I'm routing for u... and waiting impatiently for ur next video!

From both you and me have same nail, I believe we think the same way too! I like your idea and work as well!

And he's using the correct units! +10 points!

Great ingenuity and an amazing project !

woooow great job this is awesame i understand 20% what you talk but with all thge eefort to explain and show results is very entertaining

This is fascinating, Excellent video

Great video. One bonus for your tip for the cleanup of steel wool with a magnet, is to put the magnet into a plastic bag first. Then when you're done you can just fold over the bag and remove the clean magnet :)

This is great. Can't wait for part 3

I understood 100% of ±1% of the physics/maths involved, but man was this video fascinating!

Really interesting, subscribed for the next one!

Discovered your channel by this video and I enjoyed the very well prepared explanations. You are an interesting teacher ;-)

Found your channel through the submersible kayak project, and just wanna say that you have some really cool videos in the same vein as old style channels like TKoR and HouseholdHacker. You have earned a sub from me, and I hope you put out plenty of interesting projects in the future.

This is so cool, thanks for uploading it

Simplest way to give these 3D printed parts better performance and tolerances is to press in some bushings, typically made from brass. It works similar to putting in inserts, heating them up and then just pushing. Bushings are very often the better solution compared to roller or ball bearings anyway.

@dustinbrueggemann1875

Жыл бұрын

Bushings are only really significantly better if you're worried about contaminant intrusions into the race or concentricity. For a continuous low speed, ambient temperature, high torque system in an open and dry environment, ball bearings are pretty much perfect. A bushing would need much more careful tolerances for the shafts and alignment. If he were working with hydrogen gas you might have an argument though.

@graealex

Жыл бұрын

@@dustinbrueggemann1875 Yes yes, high torque like here lol. It's low-torque, low-load, low-speed, and very limited operating hours, so the main argument for bushings is the fact that they're low profile. Which I guess is the reason he didn't install ball bearings in the first iteration of the rod, as there wasn't enough space.

You need a patreon or something. Some people might wanna throw money at you? What you're doing is refreshing. Happy New Year.

Definitely a sub from me! Love this controlled testing and iteration, looking forward to seeing how cold you can go :)

Very interesting! Thanks for making these videos.

Really interesting subject !! Keep going on this way. Guillaume from France.

You have gotten a great deal of positive remarks in the comments and that is well deserved. Very scientific and a high llvel of curiosity in exploring the possibilities and also with a good intuition as where to go next. The material is clearly well understood and very well explained. You are talented! A few suggestions: Using matt black plating for internal parts in the hot zone may help in capturing some of the IR radiation of the heat and liquid cooling on the outside seems obvious to you already. Your idea of pressurizing the system looks promissing but at the cost of added complexity. If this works, a duall piston system (opposed) may help in balancing the forces especially at start up. I have seen the comment about using bushing inserts as they are cheap and easy to use (good idea). I have used ball bearings as inserts in 3D parts as well and that works well (relatively inexpensive). Just a thought: stacking pellets of perforated sheet metal with the correct size, apperture, colour and conductivity may help in capturing the heat in the hot zone. Good luck with your project.

Super interesting deep dive. Thank you!

Very interesting project. This can definitely be used with renewable energy.

Great job explaining the physics

Stumbled upon this channel, instantly subscribed! This is really cool stuff, pun intended.