To clearify how i got to the result as seen in the video: To charge: ~12.08V x ~1.62A x 43.709 seconds = 860,64 watt-second (or joules) After a discharge: ~9.42V x ~1.15A x 57.993 seconds = 628,24 watt-second (or joules) All value's are measured by the Arduino Nano in combination with the INA3221 Power monitor module. As many of you have pointed out in the comments below, I did indeed make a mistake regarding the mention of the Watt to energy aspect. My sincere apologies for that! The core of this project was to explore, show and see what was possible with this experimental project, even with some limitations. Sometimes it's not just about the final outcome, but also about the journey and what we learn along the way. And I hope that despite any shortcomings, you still found the video interesting and/or inspiring!🤓
bring the output so that it will be a stable usb-c pd and try to use a laptop with that energy, and see based on absorption if it's usable, because a larger scale version of this would mean being able to charge it with solar and release later on in a size that is way larger than car batteries( in parallel and series) that i have sometimes seen( also a cost analysis would be nice).
A potential problem with your aproach is that if you whant to store energy for long periods like hours or days, the air will slowly sip inside the cilinders, resulting in potential energy loss. and you needing to reassemble the entire rig to get rid of the air that laked iside the tubes.
This is basically the inside-out version of compressed air energy storage, except the maximum pressure difference is 1bar compared to the 80bar used in commercial compressed air energy storage solutions.
Actually it is not "basically the same". This one here has a major advantage! When compressing a gas (air) and releasing it, you do temperature changes, whether you like it or not. This eats up your efficiency. Here you do not compress, so you do not have this issue!
@@romanp.5236 makes you wonder how hard it would be to convert a compressed air energy storage to one of these types of batteries and what the difference in efficiency will be doesnt it
@@romanp.5236 you get the same rate of heat increase/decrease when pulling a vacuum as when pressurizing. The only difference is the amount of pressure differential, which in this case is necessarily limited to 1 atmosphere of pressure.
What sets this apart from compressed air energy storage is that the pressure differential remains basically unchanged while charging/discharging and never exceeds 1 bar, since the limiting factor is the atmosphere itself. That can be an advantage, because the power output remains constant, but also a disadvantage because you need significantly bigger tanks to store the same amount of energy. Fun fact: since you can't do weightlifting exercices on the ISS for obvious reasons, NASA had to come up with a special apparatus to allow for a similar type of exercice so astronauts can keep their bones healthy (living in microgravity for months at a time can lead to dangerous loss in bone density because you're not straining your skeleton as much, since you don't weigh anything). You might think "well just have them push against a piston or a spring instead of lifting a weight" but the issue is that in both cases, the amount of force required increases as you compress the spring/volume of gas (as described by hooke's law), whereas the force needed to lift a known weight remains constant. So, instead, they make astronaut pull a vacuum inside a reservoir, the same way you did here, because then you're pushing against the air pressure inside the ISS instead of trying to compress a comparatively smaller volume of air at an ever increasing pressure. This way, the pressure exerted on the piston remains basically the same, meaning the amount of force astronauts need to exert during their workout remains the same all throughout!
You can improve efficiency by making the tubes larger in diameter, and less tubes. This will reduce contact area of the plunger to the walls massively and therefore losses due to friction.
That would increase the pressure and thus making his seals fail quicker... Nevertheless it is working by using vacuum pressure so it is limited in the amount of energy stored per volume compared to a compressed air storage. i think 1 bar was less than 20% of a kWh per cubic meter. which is 1000 liters and those tubes maybe had 1 liter each ;)
So if it takes less energy to store, and you get the same energy out... it doesn't matter that it's a vacuum. It's the differential that is important. I don't think seal failure would be any different. I'm not talking about 100degree differences... I'm talking about normal atmospherical temperature differences from night/day. It doesn't make sense if you have to create heat/cold. I'm thinking you're just being obtuse.
Kinda, in theory, in purely static or dynamic scenarios, with rigid bodies. adhesive force is proportional to the surface of contact, and rubbers are very adhesive
Honestly, 73% for an amateur prototype of a device like this is pretty good. Industrializing this would likely allow for >80% efficiency. Still pretty cool video.
I didn't mention it in the video but i did indeed have to test a number of lubricants to minimize friction as much as possible! I started with dish soap and a bit of water and eventually, after Vaseline, WD40, PTFE spray and even a combination of some of them, I ended up with silicone oil, which I can say works extremely well!
@@ConceptCraftedCreations Wouldn't brass tubing also decrease the friction? Or another cheaper but lower friction material? I honestly would love to see this explored more and see how high you can get that efficiency up.
Did it? I thought the efficiency captured it nicely. Though efficiency also captured the heat of the motors. It didn't capture the efficiency of generating the electricity in the first place so I think it matters where you draw the box to define the system.😊
Watt is a unit of power, not energy. You didn't achieve an efficiency of 73%, those motors aren't efficient enough to turn electric power into mechanical work and back to electric power at anywhere near 73% round trip efficiency, even without all that additional friction you have in that system. The biggest fundamental and unavoidable issue with vacuum energy storage is the extreme cost per unit of capacity. Compressed air energy storage is difficult to make meaningful in comparison to other alternatives, but many times better than vacuum energy storage, in multiple ways. For the same volume, a vacuum chamber can only store as much energy as a pressure tank with one atmosphere "gauge pressure", or two atmospheres absolute pressure, and it's easier to make a pressure tank that holds 10 atmospheres gauge pressure than it is to make a vacuum chamber of the same volume. With all that work put into it, and it looked really nice, I wish you'd gotten the technical parts about the capacity and efficiency right.
Thanks for your comment and feedback!👌 The core of this project was to explore and see what was possible, even with some limitations. Regarding the watt-to-energy aspect, you're correct that watts are a measure of power, and I appreciate the correction. To clearify how i got to the result you see in the video: To charge: ~12.08V x ~1.62A x 43.709 seconds = 860,64 Watt After a discharge: ~9.42V x ~1.15A x 57.993 seconds = 628,24 Watt All value's are measured by the Arduino Nano in combination with the INA3221 Power module. I will work on refining my future explanations to provide a better understanding of the technical aspects. Thanks for pointing that out! I hope that despite any shortcomings, you still found the video interesting and inspiring. Sometimes it's not just about the final outcome, but also about the journey and what we learn along the way. I'm always happy to receive feedback and suggestions for improvement, and I hope you'll continue to watch my future projects!😊
@@ConceptCraftedCreationsCame to say the same as above. It is an accurate assessment. You are probably in the 25-30% efficiency range as those motors aren't very efficient. If you can measure your current and voltage over time (sampling at something like every 10th of a second) you can calculate your actual power use. I also recommend pressure storage instead of vacuum as it removes the 1 ATM limit on storage. However, I want to add that pressure storage really comes down to a strength and cost of materials issue. You can calculate it out to a point where you can show a figure of cost/yield strength and plot all the materials. There are other factors to consider though (like the safety of a high pressure tank full of lots of energy). Vacuum in theory could be just as economic, but has a problem outward pressure doesn't have. Buckling. To make a storage system economical you would need to use the materials to the edge of their safe limits. So 1ATM would be a very thin tube for most stronger materials. However that force is pushing inward. This causes the tube to warp and collapse in on itself (buckle). Outward force won't cause that, so for the same gage pressure a much thinner tube can be used. Vacuum pressure does have an advantage in that it is nearly constant however, which works really well for getting a constant pulling force over a distance and making the generation and tensioning system much simpler. I looked at all sorts of energy storage options years ago. Mass/gravity systems take enormous masses to be effective and is why really only pumped storage is practical. Inertia is decent for short term storage, but friction catches up to you for longer term. Safety of a spinning disk is also a consideration. Pressure stores moderate amounts of energy, but also creates a huge bomb to rupture at some future date. Capacitors don't store enough energy, but are great at buffering changes in charge and discharge rates. Chemical has been pretty inefficient and low storage amounts in all but the latest generation of batteries. The cost has been pretty high until the last 15 or so years too. There are other technologies making fuels that have some promise. Electrolysis and H2 storage could be practical for a fixed facility. I don't see it being practical for vehicles. There are too many conversion losses and safety issues to address that drive the cost way too high (they can be overcome, it just costs a lot). Internal stress (springs) don't store enough to be practical for the cost of materials used. Thermal storage can be very practical, particularly if it doesn't need to be converted to higher quality energy like electricity. Homes for instance could use store heat for space heating very effectively. It is also somewhat practical for grid scale energy storage, though I believe the plants they have built thus far are considered failures. In the end LiFe batteries are the most practical storage method available at smaller scales. They are pretty high energy density and the cost is getting pretty low. Sodium batteries will probably over take them in the next five years as the low cost option. Regardless of whether something is the best method though. It's still fun to experiment. Also sometimes efficiency is irrelevant. Sometimes it is about what you have and can achieve with it. I have interest in low temperature difference stirling engines. They will never be efficient, but if the energy source is free, sometimes efficiency doesn't matter. Good luck on your experiments. Your video was well presented.
I'd love to see the piston system being used with a valve to drive the motors in a ratchet-way so compressed air could be used to drive them. That would allow a fun test of pumped storage.
@ConceptCraftedCreations You must take in account the time needed for charging / discharging if you want an accurate evaluation of the efficiency of your battery : Efficiency=(Td x Pd) / (Tc x Pc) = Ed/Ec Td : discharging Time in seconds Pd : average discharging Power during Td in Watts Tc : charging Time in seconds Pc : average charging Power during Tc in Watts Ec : Energy needed for charging in Joules Ed : Energy recovered while discharging in Joules @fishyerik Without explaining how to correct it, pointing a mistake has low value.
This was actually pretty brilliant. A great example of lateral thinking the gravity based system. Regardless of the efficiency and others critiques, I really enjoyed this project and look forward to more.
Another question that I have is... if the tube stai there under presure for 10 days, the power wil be the same please ? I mean... can be that the air pressure lost in time ? Thanks for the video.
I was about to point that out. However, it may be worth doing this instead, because springs wear out faster when held depressed for long periods of time. Still, this atmosphere battery isn't much better, because it's likely it will lose "power"/stored energy over time due to small air leaks. Those rubber gaskets are under alot of load, and i don't imagine they'd last much longer than a spring.
@@danielmontmeny9880 The video literally showed air bubbling into the vacuum cylinder during charging. A spring is at least more efficient than that long term.
@@danielmontmeny9880 Wait a minute who told you that springs wear out when compressed? As long as they don't go beyond their elastic range a compressed spring should experience virtually no wear.
@@kieran8266 they do, it just happens rather slowly. large temperature variations can speed it up, but even considering that it'll happen orders of magnitude slower than a vacuum chamber will degrade
This is very neat but the Achilles heel is the fact that it has an upper limit on extractable force. No matter what materials or innovations you have, you can only ever get to one atmosphere of pressure. But you've kind of engineered the opposite of pneumatic storage. There's different flavours of it (cryo vs standing air) but it all works on the same principal of exploiting a pressure differential. Very cool project!
@@contafamilia2092 sure, but now you've got to maintain equipment under the ocean. Cryogenic storage does the same, but you can easily access the equipment.
A duel system of vacuum and pressure could be combined.. Double /split cilinder design would quadruple the forces... In large scale this would rate at megawatt energies
@@elderzeroremorse8582 Realistically, all you're doing is adding 1 atmosphere of pressure to a pressure vessel with a lot more over engineering. We already have composite pressure vessels that have maximum allowable working pressures of over 300 atmospheres. Adding 1 more isn't going to make a huge difference. And on top of that, using cryogenic methods over mechanical pressurization often adds more efficiency due to avoiding friction and electrical losses. Heating a cryogenic fluid to increase pressure is much more efficient than trying to mechanically compress nitrogen.
i really did not expect your losses to be at 27% i though it would be much more! i didnt expect you to beat hydro with basic tools and to be honest this could be scaled up pretty easily and fit into a home, i would be interested in its weight or volume / energy capacity but this video is very inspiring by itself. Thank you
I just loved how the moisture in the cylinders started to boil the moment you lifted the plungers. Very neat! The main disadvantage I see over pumped hydro is complexity and cost. A reservoir and a pump vs. all of this. Pumped hydro also allows easy control over discharge power over time and I think you would need a very beefy gearbox to achieve the same here. Still it's a great experiment and a very interesting result!
Yeah that was my first thought. Not to knock the video or the effort put in, quite the contrary rather. The idea has great merit if a dude can achieve 73% efficiency with home tools and a 3D printer.
@@knifeyonline Right but this is literally a desktop sized battery. Put it on the scale of space a pumped hydro station takes up and it might be viable.
I clicked on the video because I was intrigued by the idea. I didn't expect a great outcome, but I found the idea interesting. The approach was very entertaining, and adding a bit of science always enhances it! You deserve more encouragement than just open opinion or criticism. Great explanation and a nice idea; keep making this kind of content!
cool idea but your efficency calculation are wrong. Watt is the unit that mesures how mush energy is used/generated at the moment. but it is not a messuremtn of how much enegergy is stored. for that you need to take time into consideration (ie. Wh, kWh, Ws). you can have a battery that chages with 10 watts over an hour and dischage 100 watts in 2 seconds. with your calculation, it would have an efficency of 1000% and thats not the case. in reality the battery charges with 10 W over 1 hour (60 min -> 3.600 s). so it saves 36.000 WS. it discharges 100 W over 2 seconds so 200 WS. so the real effiency would be ~5,5% and not 1000%
I understand what you mean👍 and the power monitor module in combination with the Arduino Nano measured the voltage, current and time for both charging and discharging. So the wattage is, as you say, the full and actual consumption and power generated by this setup👌
@@ConceptCraftedCreations Are you saying that it took 860Wh to charge this battery? If so, this result seems unlikely because the video shows that charging takes less than a minute, which means that in order to store such energy in such a time, the engines should have a power over 50kW. You must have a miscalculation somewhere, maybe this capacity is 860mWh?
@@ConceptCraftedCreations Yep it's pretty easy to understand all the so-called people using precise exact overthinking terminology just don't understand it. you measured what it takes to charge and what it discharges.
To clearify how i got to the result you see in the video: To charge: ~12.08V x ~1.62A x 43.709 seconds = 860,64 Watt After a discharge: ~9.42V x ~1.15A x 57.993 seconds = 628,24 Watt All value's are measured by the Arduino Nano in combination with the INA3221 Power module.
pretty cool. I'm just an armchair enthusiast of energy storage but the thought experiments are fun. For a compact energy storage method with no chemical danger, no real degradation and easily serviceable parts, I think this is a pretty cool experiment. I think scaled up with some refined tolerances could absolutely get the efficiency up. The danger, of course, is large vacuum chambers, but this would be interesting to see something like this on houses. It makes me wonder if there is any potential in simple having a large vacuum chamber with a regular vacuum pump and then a valve to switch it over to a fan generator.
Pretty good results, if you improve the generators by having dedicated generators that go on with a clutch as the motors detach with another clutch the efficiency should go up by a lot and it probably will make your battery even market viable
I work with equipment that is very sensitive to atmospheric pressure changes and I will say that this energy storage is extremely interesting. Especially, in climates that have massive ambient pressure spikes.
I like it, and I think that cost and size are more important than efficiency, because these are intended as solar powered batteries. This idea doesn't require an artificial lake in mountains (die we niet hebben in Nederland) or holes in the earth. If the batteries don't get you through the night, you just need more of them. So great job!
I think this is the more important take away in that you have a small compact design with a few cheap consumables needed for maintenance. (mainly seals)
Where I live, the area has been powered by pump storage supported by various power plants since the 1980s. About 15-20 years ago though, they started putting in wind turbines. Many people were critical and still are. I think it's really cool though. In the time since they started installing the turbines, they've put enough in that the pump storage is entirely powered by wind energy and it's really cool to live 20 miles away from something like that. I feel fortunate to have such clean energy generation in my area and if I go past that, it's just a giant lake all the way to Wisconsin so the air here is pretty clean
pumped storage is such an interesting and useful idea! its so simple yet effective. it helps combat the unrealiability and demand problems of green energy by allowing the energy to be stored and made more stable!
Fantastic! The advantage to keep in mind is it's more compact than a gravity battery. Though you won't get the same efficiency per unit, you do get more capacity per volume. If you charge it with earth and solar powered Sterling engines and use flywheels you'll only have maintenance cost. I love it!
Very cool project. The design gets cool points. A few suggestions: To cut down on frictional losses, 1 vacuum chamber with a diameter optimized for ideal torque. And something to better stabilize the plungers as it looks like they are crooked in their cylinders which will reduce efficiency.
Really cool project! I think friction is your big problem. First of all. The pistons are not staying vertical as they are pulled slightly off axis by the timing belt. I'd make the pistons have skirts made of Teflon to keep them vertical. I'd also consider trying different seals on the pistons to see if there is anything capable of producing a vacuum but causing less friction. Finally, the big move is to reduce the number of pistons by increasing piston diameter. When you double the diameter, you double the friction surface, but you quadruple the displaced volume. 8 pistons looked cool. But it made the friction problem worse. It's why you don't see many small displacement, high cylinder count engines like a 2 liter V8.
@@atrumluminarium I miss him too 😭 Loosing your significant other is a tremendous blow, and then there's ALL the practical things on top Give it time, they say. I'll give him all the time he needs - and yes, I'm sure he'll have some wonderful insights on this amazing idea
That thought had occurred to me when I was contemplating the possibilities of pumping water with just gas pressure. It never would have worked because of the weight of water being what it is, but a diaphragm allows for the gas side to be completely sealed and to use a more volatile liquid to get the most range of pressures possible.
I was glad to see some more experimenting done with this concept. I started buying screen door closers for my experiments, unfortunately I never made it to any prototyping
Great Idea! One question: In the efficiency calclulation you wrote "watts" which is power, not energy (would be watthours). Were the motors consuming 860 Watt during charing and generating 628 Watt during discharging? If yes, how long does it take to charge and discharge the "battery"? - Watt * Seconds / 3600 = Watthour. Stored energy of about 700 Watthour seems to much... Thank you for your answer and keep your great work up and the RUclips channel up!
Was about to ask this as well, how long does it discharge vs charge. Having something put out 600 watts is nice an all but if it only lasts for a few seconds, that's not really much usable power
I think the best part in vacuum storage over pressure storage is the fact, that it provides linear force and can be generated and used very fast. I could see it as a kind of capacitor. Used when an excess of Mechanical energy is there that needs to be stored and then used almost instantaneous afterward, so airtightness isn't as big of a problem. I had to think of one video from Tom Scott, where he uses a Motion wheel to transfer the momentum of a bike to use it for accelerating afterward. This seems like a pretty good use case especially because it is limited energy that can be converted, and it doesn't bring any access weight with it like the flywheel.
great work so far! you should also graph, lifespan, energy density, cost per kilowatt of storage and then you would have a better idea of wear your headed, its worth noting that a prototype is probably significantly worse than it could be with upgrades
Genuinely surprised at the figures you pull out at the end. If you increase the diameter of one cylinder, you'll get proportionally less friction from the sides of the rubber gasket and you can simplify the device. Doubling the radius of the cylinder doubles the circumference but quadruples the surface area.You might also be able to put the tops of the cylinders under passive pressure to increase the force on a single piston, or put the whole device under pressure. How good are the gaskets at holding the pressure? Is there any loss over time from gasses moving from one side to the other? Can probably improve that by increasing the molecular mass of the gas that's exerting the pressure. Maybe sulphur hexaflouride? Argon might be cheaper and is definitely safer, but probably not as good. I'd also try putting bearings on the support for the gasket... how do I explain this... since the gasket needs to be kept straight, the piece the gasket is attached to is rubbing along the walls of the tube so, if you put bearings between the gasket holding thing and the tube, you'll reduce friction.
Would submerging the tubes underwater or in a pressurized air tank increase the total resistance it has to overcome thus you could increase the gear ratio to also increase run time?
I couldn’t stop thinking of using diaphragms for vacuum formation instead of pistons the entire time I was watching the video. It would eliminate leakage and friction.
friction, leakage and maintanance for this battery would be to high to be practical, But idea with diaphragms would reduce those. You could build closed sealed system with less wear. But! you can create vacum, how dou you want to turn it back to mechanical energy? they won't vibrate by constant vacum and i think mechanical solution to turn the vacum back to mechanical would add the problems back that you solved by using diaphragms :)
I'm just watching half of the video and I'm already amazed at the experimental setup you implemented for each phase. Kudos to you! BTW, which model are these motors you're using? Thanks!
Jij bent echt een maker terwijl ik vaak niet weet waar ik beginnen moet om iets om te zetten in een product of test. Ik heb nog wel wat ideeën voor je om te maken!
Awesome channel! loved the video. my only tip is regarding the video style: i would like to see the batery being used to power something in the end right before the numbers of efficiency, it helps with the story-telling if you have a "final results"/resolution part in the final edit :) keep the good work!
I think everybody here is missing the point thats its a proof of concept, some of the maths might not be exact or perfect but im sure none the less he had a alot of fun building and designing this project, learnt a bunch of things on the way. C'mon ppl his not saying he is making zero point energy just having fun expermenting with alternative battery types. Im looking forward to a MkII.. 😊
Yes, exactly what you say is indeed what I first thought when I saw all those comments coming in😄. But the other side of it is that it does spark fun discussions🤓 Thanks for your support! Appreciate it!👌
As a POC it's interesting, and it's going to spark some thought, but it's got several major challenges that will make it less than ideal for implementation. It's part of the reason the Hyperloop concept was doomed to failure after over a century of pneumatic pressurized tube passenger rail trials.
A proof of concept is supposed to show something as being feasible, this contraption is just not feasible. The friction, multiple layers of energy loss, air leaked and wear, there's just so much worse about this than a spring, compressed air storage, or even just a weight on a very rope.
Great attempt. One important thing to note is that when a load is connected to the motor the force required to to overcome inertia will be significantly more than when no load is connected. You measured the force required with no load on the motor.
Lekker man, goede video en erg interessant concept. Misschien is het nog interessant om te meten hoeveel energie je verliest als je het ding een paar uur of dagen opgeladen laat staan. Maar goed bezig, ga zo door!
Also just a crazy idea for a gravity battery that could work is turn a whole parking garage into a gravity battery. The roof can be all solar panels. It should be loaded like a spiral column with a car elevator in the middle to load and unload cars. It will double as a space saver too.
Given the easy access to the used materials and the easy way to construct it: Yes please for a bigger version! This has so many possibilities and just the reduced need of special materials makes this a very cost effective way. I love your creative engineering!
Thank you for your compliment👌 and I'm glad you enjoyed the video! This result has made me itch to start working on a large version.. So there is a good chance that this will happen in the future!🤓
@@ConceptCraftedCreations I am an engineer myself and too many of our projects are only looking at high-end solutions, that cost a fortune to build. If we really want to enable others with less financial abilities to be part of this transition, we desperately need solutions like the ones you show.
That's one of the main reasons i wanted to try this approach. To get new results, you sometimes have to try new things! And i always think that if you don't try, you won't know! Right?
Awesome project! I was thinking about making a gravity battery for the house and was thinking, that it would take heavy blocks or water, but i didn't even think about using vacuum for energy storage!!!
I think its really important to talk about energy density, cost per joule, dependancy on rare/unstastainable materials, easy of manufacture, room for inovatiom, scalabilty etc when talking a novel energy storage technique. If this is a standout in just 1 area, then there's a great niche for this
It's fine. He's measuring the power in and out. Energy is going to have a linear relationship to that. It's the same as when people talk about their weight in kg. We understand what it means.
@@JohnDoe-ej3wp Yes and no. Depends if he is measuring stuff for the same duration. But yeah, it's just a physics thing. He is actually measuring Joules, just said it was watts
Its the most efficient way if doing it. Wdym lmao. You cant find current without both volts and amps. You can convert your current to whatever you want, 1000000 volts or 3 volts. The only important part is the wattage. Its just amps X volts.
@@TheAshYam Not really. The important part here was Joules because he wanted to know the efficiency of the battery. Watts is useful to calculate Joules. The main issue was the nomenclature because he ended up calculating Joules, but called them watts
Neat but dude come on, just use a spring! ... it's basically already working as one and you are just complicating it with all those rubber seals that will need lubrication and still fail in a couple of thousand cycles. Using a steel spring would be so simple and just as effective.
Sure, but it feels scaling this up would be easier than mass producing giant size springs. But then again I have no clue about the spring industry :D so it would be a question of price and availability
I have always been interested in gravity energy storage. This was a fascinating concept and design. At 73% and being a prototype only.. there is always a lot of room for improvement. Especially with a team of engineers. On that note. This holds good potential. Thank you for the video!
If there is a place that has a change in pressure, perhaps movement between the two places could make this viable. Like a space elevator. The change in pressure between the two places could charge a battery with this concept. Kinda like temperature difference in the ocean but too much of that could have adverse effects on the ecosystem. I was going to point out that friction and the strength of the tubes are your biggest efficiency obstacles (mentioned in comments but not the video). Higher quality and tougher materials could improve the numbers but this video still did a great job explaining the concept. Gotta withstand the pressure and friction.
No worries about the efficiency. For a prototype that could benefit from scaling and optimization, 73% is remarkable! Very nice concept. If you make a larger model, I think the efficiency will improve because the losses due to friction will be relatively smaller. All good wishes.
To compare you should also consider: -volume density -weight density -cost -safety I'd love to see a full ocmparison with standard storage (batteries, mechanical storage, etc)
The problem with storing energy in vacuum is buckling instability in the storage vessel due to compressive forces acting on thin shells. It is why vacuum tanks end up being thick and bulky with high embodied energy. A concrete or even rammed earth vac tank may be the way to go for the rough vacuum needed for energy storage. The energy storage density is low, so the materials used to make the tank need to be energy cheap.
0:47 They've been trying to sort something like that out, based on that gravity and weight principle, in large scale to work with hydrogen fuel cells to store excess energy from wind turbines during the day and then to use the stored energy at night. Cool stuff.
Brilliant! Manufacturing this in large scale wouldn't generate toxic waste and if there was structural failure, it wouldn't explode, burn, or collapse, but just slurp up air.😃
Reduce the friction when the belt tightens. When it releases it will bind resulting in power loss do to frictional force. Alternator concept would apply greatly here which is theoretically what you are doing. Id love to be of help if any. I spoke to my stepdad about this when before now I’m seeing it and the fact it works and he doubted me, so i never birthed it into fruition like you did. Good job man! You completed something i have always thought about
I would be interested in volumetric and mass energy density of this system. Did you measure them? Is this viable for mobile applications or just for stationary use?
This is a remarkable idea, smaller and safer than some others I’ve been pondering. If a flywheel breaks, it’s a very bad day for everyone. Maybe even the neighbors. But if this breaks it will be pretty loud but not all that dangerous. I’d like to see one scaled up to the size of a large hot water heater. Something that could sit in the corner of a basement. In conjunction with rooftop solar and a moderate home backup battery system it could be pretty amazing.
You could probably greatly improve it by reducing friction. You might be able to do this in a few ways. My first couple suggestions are these: 1: Add braces between the tubes so that they do not flex side-to-side under pressure. If the tube bends, then the piston ends up being forced through a curve rather than a straight line. This creates unnecessary tension and friction. 2: For the same reason as the horizontal braces between the tubes, you could consider placing vertical braces between the base and top of your contraption. These would remove a lot of the downward stress, which is currently being applied directly to the vacuum tubes, causing them to flex. 3: A slight bit of oil to lubricate the seals at the end of the piston would probably go a long way in reducing friction. Those are just the first things that come to mind, though. I enjoyed watching. This is a very interesting concept.
Glad I found your channel. I look forward to watching other people teach things my curiosity lives on. Awesome job and best luck to your channel. Look forward to seeing everything you have to share!
There's a few things I think It would be worth testing: - Scaling up from 8 to 16 tubes and seeing if you get double or more than double the energy storage - longevity testing - how many charge/discharge cycles can you get before the rubber seals wear out and then you can calculate the ongoing cost to maintain this type of battery - there are applications where longevity and weight matter more than size - if this design can be made in a manner that a few pieces of rubber can be swapped out in an hour for n thousand charge/discharge cycles then it could be quite cost effective against chemical batteries in high cycle applications
Probably the coolest novel probably energy storage idea I’ve seen in a long while! Get that patent quick! If it truly rivals hydro storage then you have a much smaller more eco friendly power storage option which our future clearly needs! Definitely say try a larger scale design and see how the numbers compare with scale.
Nice concept, I already detected some advantages of this concept: - It is easy to scale up the capacity by using bigger diameter for pistons or more pistons. While the other concepts are harder to scale up. The scalability is of power 2 order. i.e twice the diameter gathers 4 times more force from the atmosphere. - There is probably a way to enhance efficiency: using bigger diameter pistons and reducing the piston course (displacement), this may reduce the friction. Not sure, this needs some computation and tests. With a bigger diameter and lesser length we have a bigger surface of friction but acting on less length. The friction is caused by the normal force acting on the cylinder by the deformation of the joint, will this force be bigger or lesser with a bigger diameter?
Wait now take this an make it powered from the atmosphere pressure changes. Place the pistons in the middle of the stroke on a day of natural air pressure. On days when storms move in the atmosphere pressure will drop this causing piston movement and thus energy.
As you noted this is similar to pumped hydro. You could achieve the same with moving water and its less likely to leak as water seals are easier to maintain than air seals. But here is an idea you can't do with pumped hydro. Air pressure is always changing. If something is changing we can harvest energy when it moves from a high stored energy to a low. Think about building a pressure vessel with one way valve. When the air pressure goes up it overcomes the valve and equalizes the pressure inside the vessel. When the air pressure goes down you can harvest the pressure from vessel as you allow it to escape. The interesting thing is that this can happen passively and you can sale the vessel to be very large capturing more energy.
As for using old mineshafts for energy storage with weights mentioned in the start, I really have my doubts about the viability of that from a practical standpoint. I work in the mining industry as a geologist and maintaining an abandoned mine is very expensive and a huge liability. Underground mines are almost always below the water table, so there needs to be constant pumping and maintenance done to prevent flooding. The ventilation would also need to be maintained to prevent explosive gas buildups. Any unsealed areas could leech more toxic materials into the mine water. And mines are naturally unstable, they will collapse eventually.
One thing you should consider in addition to efficiency is the size of the system. How big would a full-scale machine need to be to store and then release the same amount of energy as that of a pumped hydro for instance? Unlike compressed air batteries, the pressure difference between the inside and the outside is not higher than one atmosphere, so to generate more energy you must build a bigger machine (i.e. a bigger vacuum volume). However, with compressed air, you can increase stored air pressure by using stronger materials or thicker metal without much increasing the machine's size.
in the very last shot of the machine working, I'm seeing air bubbles leaking in through the bottom seal. If that's the case then improvements on the seals would increase the efficiency. larger versions are going to suffer from crush pressure of the tubes. even if they don' implode they could bend, warp or buckle somewhat inelastically and I can only imagine that would cause problems. I'm sure you'll be able to account for that but be sure to do the calculations on material strength if you go bigger. implosion can be dangerous. I love this. Great video. more, more, more.
I like the way you think! I subscribed immediately. I would call this a pneumatic battery, or maybe a vacuum battery. Well done! For our North American friends, 1910g = 4.2 pounds.
You should try testing this with a large capacity commercial air compressor. That's honestly the only way you might be able to test this at a larger scale, but you won't be able to use the same motor that compressed or decompressed the air. I am not sure was expecting in terms of efficiency before you got your results, but it would make sense that it would be closer to the same as hydro, because it kind of works under a very similar principal because air is technically considered under fluid mechanics, but this is technically more like a spring so it's not quite the same as the type of fluid mechanics we were comparing it to earlier. I think with a larger scale with better seals, you might be able to get even more efficiency out of it.
It’s an interesting concept. The main problem is that it’s dependent on the pressure of the atmosphere. I would suggest doing it under water for wave power or sea wind farms or adding a weight to the plunger and combining it with a gravity battery.
I am no engineer, but impressive to me. Few potential improvements. 1) Belts are less efficient than chains. Maybe, the linear motion required could be achieved with toothed rods and gears. 2) larger diameter tubes and less of them would be less surface area on seals. 3) could be worth seeing what % vacuum achieves the greatest efficiency. Maybe only charging to 50% is more efficient than to 100% (or some value other than 100%). As you have a prototype, could be worth exploring patents in this area and seeing if you could patent it. It being lower efficiency than batteries which are the only other worthwhile home storage solution (maybe gyro too) is fine as this is much simpler to build and doesn't require rare earth metals (well... magnets in the motors but still).
A beautifully executed experiment with interesting results. I fear a full sized version might prove that making a vacuum vessel large enough, yet strong enough to avoid collapse might prove too difficult
Excellent idea. Ya know there are a lot of inventions with or without patens that are out there that didn't work at the time they were created, but they really need to be revisited, because now we have the technology and the ability to take some of these ideas to the next level. There are numerous creations just waiting for the right person to come along and use them.
Amazingly good results for this system. In theory, when you lowered the pressure in the cylinder, the temperature decreased. This temperature gradient would cause the air inside the cylinder to absorb energy from the ambient air outside the cylinder. This obviously makes the system less efficient. I wonder if insulting the cylinders would provide even greater efficiency? Very interesting idea that you have developed.
Considering the ideal gas law: PV = nRT I'd love to see you incorporate an efficient thermal aspect to this design to see if you can further improve the efficiency of storage / discharge.
This should definitely be invested in and upscale if not for future use than for experimental purposes testing to see what parts wear out, how long it takes each part to wear out, what caused the malfunction, and then what it would cost to make the repair and how much time it would consume. I think this is worth further investigation.
if you were thinking about long-term, as one who uses an AeroPress to make coffee and had to replace their seal recently, one potential downside I foresee is the wear/tear on rubber. Not an big issue in your prototype, but certainly an issue if scaled to industrial size.
Very cool. Without running the math - my intuition is that energy density will be the main problem with this. 1 bar of pressure is going to have a pretty low hard density limit - making it impractical. If to power a house for a day you need more volume than the house then the problems of scaling become obvious in a way it isn't on a model.
Please forgive me if it is nonsense, but I have a few ideas: Would compressing air instead of creating a vacuum work as well / would it be less or more efficient? Could you increase the efficiency if you minimize friction beetween the tubes and seals? Great project, really. I am not a professional in this area, but with stronger materials etc. this seems like it has potential. Cool.
Neat Idea, I like the fact it's compact, easy to make (relatively), and doesn't use toxic chemicals. The only major "con" would be the maintenance on storing the energy long term. Holding vacuum is a active process and it will leak over time, which will require energy to maintain. A gravity battery like stored hydro, is passive as you only have to pump the water once. It's more efficient, but is not as compact, and requires a large head span. Could you not swap out the vacuum with an 80kg weight and simply do a linear generator? or what about using a spring with a resistance of 80kg?
I my self see some improvements they can be made, 1 some type of thin lubricant would be great. 2 because of the high friction the motors are just working too hard to pull all simotanusly, make a mechanical configuration that will do it two or one at the time, so basically you fight against friction. 3 most important, if you have more tubes you will have more power stored so it will potentially heighten the efficiency. 4 siquentional vacuum, and sinquensional pressure 5 I don’t know for sure if a vacuum pump would help for another project :)
To clearify how i got to the result as seen in the video:
To charge: ~12.08V x ~1.62A x 43.709 seconds = 860,64 watt-second (or joules)
After a discharge: ~9.42V x ~1.15A x 57.993 seconds = 628,24 watt-second (or joules)
All value's are measured by the Arduino Nano in combination with the INA3221 Power monitor module.
As many of you have pointed out in the comments below, I did indeed make a mistake regarding the mention of the Watt to energy aspect. My sincere apologies for that!
The core of this project was to explore, show and see what was possible with this experimental project, even with some limitations. Sometimes it's not just about the final outcome, but also about the journey and what we learn along the way. And I hope that despite any shortcomings, you still found the video interesting and/or inspiring!🤓
Would have loved to see it charge something.
Just a thought, but maybe to make it basically 100% effective, by not using the motors to charge it. Make it hand cranked or something.
bring the output so that it will be a stable usb-c pd and try to use a laptop with that energy, and see based on absorption if it's usable, because a larger scale version of this would mean being able to charge it with solar and release later on in a size that is way larger than car batteries( in parallel and series) that i have sometimes seen( also a cost analysis would be nice).
How much energy did you loose by friction on the tube walls and pulleys
A potential problem with your aproach is that if you whant to store energy for long periods like hours or days, the air will slowly sip inside the cilinders, resulting in potential energy loss. and you needing to reassemble the entire rig to get rid of the air that laked iside the tubes.
This is basically the inside-out version of compressed air energy storage, except the maximum pressure difference is 1bar compared to the 80bar used in commercial compressed air energy storage solutions.
Actually it is not "basically the same". This one here has a major advantage!
When compressing a gas (air) and releasing it, you do temperature changes, whether you like it or not. This eats up your efficiency.
Here you do not compress, so you do not have this issue!
@@romanp.5236 makes you wonder how hard it would be to convert a compressed air energy storage to one of these types of batteries and what the difference in efficiency will be doesnt it
@@romanp.5236 When you pull a vacuum, you're just pumping heat into the cylinder instead of out of it? How would that not be the same on both sides?
@@romanp.5236 you get the same rate of heat increase/decrease when pulling a vacuum as when pressurizing. The only difference is the amount of pressure differential, which in this case is necessarily limited to 1 atmosphere of pressure.
@@faethewolf I disagree. If you start from a perfectly empty syringe and just increase the empty volume, no gas is there to cool down.
What sets this apart from compressed air energy storage is that the pressure differential remains basically unchanged while charging/discharging and never exceeds 1 bar, since the limiting factor is the atmosphere itself. That can be an advantage, because the power output remains constant, but also a disadvantage because you need significantly bigger tanks to store the same amount of energy.
Fun fact: since you can't do weightlifting exercices on the ISS for obvious reasons, NASA had to come up with a special apparatus to allow for a similar type of exercice so astronauts can keep their bones healthy (living in microgravity for months at a time can lead to dangerous loss in bone density because you're not straining your skeleton as much, since you don't weigh anything). You might think "well just have them push against a piston or a spring instead of lifting a weight" but the issue is that in both cases, the amount of force required increases as you compress the spring/volume of gas (as described by hooke's law), whereas the force needed to lift a known weight remains constant. So, instead, they make astronaut pull a vacuum inside a reservoir, the same way you did here, because then you're pushing against the air pressure inside the ISS instead of trying to compress a comparatively smaller volume of air at an ever increasing pressure. This way, the pressure exerted on the piston remains basically the same, meaning the amount of force astronauts need to exert during their workout remains the same all throughout!
I learned a lot from this video and this comment
It's called a rubber band jffc smffh u go nasa fkn morons I swear
73% on a small scale model and with all the unavoidable friction at this size is amazing! Very inspiring!
You can improve efficiency by making the tubes larger in diameter, and less tubes. This will reduce contact area of the plunger to the walls massively and therefore losses due to friction.
You could probably increase efficiency using thermodynamics too. Store while warm discharge cold..
Nope. Friction is independent of area of contact.
That would increase the pressure and thus making his seals fail quicker...
Nevertheless it is working by using vacuum pressure so it is limited in the amount of energy stored per volume compared to a compressed air storage. i think 1 bar was less than 20% of a kWh per cubic meter. which is 1000 liters and those tubes maybe had 1 liter each ;)
So if it takes less energy to store, and you get the same energy out... it doesn't matter that it's a vacuum. It's the differential that is important. I don't think seal failure would be any different. I'm not talking about 100degree differences... I'm talking about normal atmospherical temperature differences from night/day. It doesn't make sense if you have to create heat/cold.
I'm thinking you're just being obtuse.
Kinda, in theory, in purely static or dynamic scenarios, with rigid bodies.
adhesive force is proportional to the surface of contact, and rubbers are very adhesive
Honestly, 73% for an amateur prototype of a device like this is pretty good. Industrializing this would likely allow for >80% efficiency. Still pretty cool video.
If only friction of the seal did not completely kill his maths.
I didn't mention it in the video but i did indeed have to test a number of lubricants to minimize friction as much as possible! I started with dish soap and a bit of water and eventually, after Vaseline, WD40, PTFE spray and even a combination of some of them, I ended up with silicone oil, which I can say works extremely well!
@@ConceptCraftedCreations Wouldn't brass tubing also decrease the friction? Or another cheaper but lower friction material? I honestly would love to see this explored more and see how high you can get that efficiency up.
@@picklesdill5462 It needs to be airtight over extended periods
Did it? I thought the efficiency captured it nicely. Though efficiency also captured the heat of the motors. It didn't capture the efficiency of generating the electricity in the first place so I think it matters where you draw the box to define the system.😊
@@ConceptCraftedCreations is silicon oil work great for some me time?
Watt is a unit of power, not energy. You didn't achieve an efficiency of 73%, those motors aren't efficient enough to turn electric power into mechanical work and back to electric power at anywhere near 73% round trip efficiency, even without all that additional friction you have in that system.
The biggest fundamental and unavoidable issue with vacuum energy storage is the extreme cost per unit of capacity. Compressed air energy storage is difficult to make meaningful in comparison to other alternatives, but many times better than vacuum energy storage, in multiple ways. For the same volume, a vacuum chamber can only store as much energy as a pressure tank with one atmosphere "gauge pressure", or two atmospheres absolute pressure, and it's easier to make a pressure tank that holds 10 atmospheres gauge pressure than it is to make a vacuum chamber of the same volume.
With all that work put into it, and it looked really nice, I wish you'd gotten the technical parts about the capacity and efficiency right.
Thanks for your comment and feedback!👌
The core of this project was to explore and see what was possible, even with some limitations.
Regarding the watt-to-energy aspect, you're correct that watts are a measure of power, and I appreciate the correction.
To clearify how i got to the result you see in the video:
To charge: ~12.08V x ~1.62A x 43.709 seconds = 860,64 Watt
After a discharge: ~9.42V x ~1.15A x 57.993 seconds = 628,24 Watt
All value's are measured by the Arduino Nano in combination with the INA3221 Power module.
I will work on refining my future explanations to provide a better understanding of the technical aspects. Thanks for pointing that out!
I hope that despite any shortcomings, you still found the video interesting and inspiring. Sometimes it's not just about the final outcome, but also about the journey and what we learn along the way.
I'm always happy to receive feedback and suggestions for improvement, and I hope you'll continue to watch my future projects!😊
@@ConceptCraftedCreationsCame to say the same as above. It is an accurate assessment. You are probably in the 25-30% efficiency range as those motors aren't very efficient. If you can measure your current and voltage over time (sampling at something like every 10th of a second) you can calculate your actual power use.
I also recommend pressure storage instead of vacuum as it removes the 1 ATM limit on storage. However, I want to add that pressure storage really comes down to a strength and cost of materials issue. You can calculate it out to a point where you can show a figure of cost/yield strength and plot all the materials. There are other factors to consider though (like the safety of a high pressure tank full of lots of energy). Vacuum in theory could be just as economic, but has a problem outward pressure doesn't have. Buckling. To make a storage system economical you would need to use the materials to the edge of their safe limits. So 1ATM would be a very thin tube for most stronger materials. However that force is pushing inward. This causes the tube to warp and collapse in on itself (buckle). Outward force won't cause that, so for the same gage pressure a much thinner tube can be used.
Vacuum pressure does have an advantage in that it is nearly constant however, which works really well for getting a constant pulling force over a distance and making the generation and tensioning system much simpler.
I looked at all sorts of energy storage options years ago.
Mass/gravity systems take enormous masses to be effective and is why really only pumped storage is practical.
Inertia is decent for short term storage, but friction catches up to you for longer term. Safety of a spinning disk is also a consideration.
Pressure stores moderate amounts of energy, but also creates a huge bomb to rupture at some future date.
Capacitors don't store enough energy, but are great at buffering changes in charge and discharge rates.
Chemical has been pretty inefficient and low storage amounts in all but the latest generation of batteries. The cost has been pretty high until the last 15 or so years too. There are other technologies making fuels that have some promise.
Electrolysis and H2 storage could be practical for a fixed facility. I don't see it being practical for vehicles. There are too many conversion losses and safety issues to address that drive the cost way too high (they can be overcome, it just costs a lot).
Internal stress (springs) don't store enough to be practical for the cost of materials used.
Thermal storage can be very practical, particularly if it doesn't need to be converted to higher quality energy like electricity. Homes for instance could use store heat for space heating very effectively.
It is also somewhat practical for grid scale energy storage, though I believe the plants they have built thus far are considered failures.
In the end LiFe batteries are the most practical storage method available at smaller scales. They are pretty high energy density and the cost is getting pretty low. Sodium batteries will probably over take them in the next five years as the low cost option.
Regardless of whether something is the best method though. It's still fun to experiment. Also sometimes efficiency is irrelevant. Sometimes it is about what you have and can achieve with it. I have interest in low temperature difference stirling engines. They will never be efficient, but if the energy source is free, sometimes efficiency doesn't matter.
Good luck on your experiments. Your video was well presented.
I'd love to see the piston system being used with a valve to drive the motors in a ratchet-way so compressed air could be used to drive them.
That would allow a fun test of pumped storage.
@@court2379 Good breakdown and accurate afaik.
@ConceptCraftedCreations You must take in account the time needed for charging / discharging if you want an accurate evaluation of the efficiency of your battery :
Efficiency=(Td x Pd) / (Tc x Pc) = Ed/Ec
Td : discharging Time in seconds
Pd : average discharging Power during Td in Watts
Tc : charging Time in seconds
Pc : average charging Power during Tc in Watts
Ec : Energy needed for charging in Joules
Ed : Energy recovered while discharging in Joules
@fishyerik Without explaining how to correct it, pointing a mistake has low value.
This was actually pretty brilliant. A great example of lateral thinking the gravity based system. Regardless of the efficiency and others critiques, I really enjoyed this project and look forward to more.
Another question that I have is... if the tube stai there under presure for 10 days, the power wil be the same please ?
I mean... can be that the air pressure lost in time ?
Thanks for the video.
Pretty sure this whole Rube-Goldberg can be replaced with a garage door spring.
I was about to point that out. However, it may be worth doing this instead, because springs wear out faster when held depressed for long periods of time. Still, this atmosphere battery isn't much better, because it's likely it will lose "power"/stored energy over time due to small air leaks. Those rubber gaskets are under alot of load, and i don't imagine they'd last much longer than a spring.
it can be replaced with capacitors, and be smaller and cheaper.
@@danielmontmeny9880 The video literally showed air bubbling into the vacuum cylinder during charging. A spring is at least more efficient than that long term.
@@danielmontmeny9880 Wait a minute who told you that springs wear out when compressed? As long as they don't go beyond their elastic range a compressed spring should experience virtually no wear.
@@kieran8266 they do, it just happens rather slowly. large temperature variations can speed it up, but even considering that it'll happen orders of magnitude slower than a vacuum chamber will degrade
This is very neat but the Achilles heel is the fact that it has an upper limit on extractable force. No matter what materials or innovations you have, you can only ever get to one atmosphere of pressure.
But you've kind of engineered the opposite of pneumatic storage. There's different flavours of it (cryo vs standing air) but it all works on the same principal of exploiting a pressure differential.
Very cool project!
What about taking advantage of the pressure of the ocean by having a plant deep underwater? Could it work?
@@contafamilia2092 sure, but now you've got to maintain equipment under the ocean. Cryogenic storage does the same, but you can easily access the equipment.
A duel system of vacuum and pressure could be combined.. Double /split cilinder design would quadruple the forces... In large scale this would rate at megawatt energies
@@elderzeroremorse8582 Realistically, all you're doing is adding 1 atmosphere of pressure to a pressure vessel with a lot more over engineering.
We already have composite pressure vessels that have maximum allowable working pressures of over 300 atmospheres. Adding 1 more isn't going to make a huge difference.
And on top of that, using cryogenic methods over mechanical pressurization often adds more efficiency due to avoiding friction and electrical losses.
Heating a cryogenic fluid to increase pressure is much more efficient than trying to mechanically compress nitrogen.
you have to put this into a pressurized chamber and it will fix this problem
i really did not expect your losses to be at 27% i though it would be much more! i didnt expect you to beat hydro with basic tools and to be honest this could be scaled up pretty easily and fit into a home, i would be interested in its weight or volume / energy capacity but this video is very inspiring by itself. Thank you
I just loved how the moisture in the cylinders started to boil the moment you lifted the plungers. Very neat! The main disadvantage I see over pumped hydro is complexity and cost. A reservoir and a pump vs. all of this. Pumped hydro also allows easy control over discharge power over time and I think you would need a very beefy gearbox to achieve the same here. Still it's a great experiment and a very interesting result!
73% is pretty damn good for not having a team of engineers perfect and tweak it over decades. Definitely some potential there for improvement.
This.
yeah, but the problem is still energy density
@@concadium hey it just needs to be about 15 times greater and then it's worth using 😁
Yeah that was my first thought. Not to knock the video or the effort put in, quite the contrary rather. The idea has great merit if a dude can achieve 73% efficiency with home tools and a 3D printer.
@@knifeyonline Right but this is literally a desktop sized battery. Put it on the scale of space a pumped hydro station takes up and it might be viable.
I clicked on the video because I was intrigued by the idea. I didn't expect a great outcome, but I found the idea interesting. The approach was very entertaining, and adding a bit of science always enhances it! You deserve more encouragement than just open opinion or criticism. Great explanation and a nice idea; keep making this kind of content!
cool idea but your efficency calculation are wrong. Watt is the unit that mesures how mush energy is used/generated at the moment. but it is not a messuremtn of how much enegergy is stored. for that you need to take time into consideration (ie. Wh, kWh, Ws). you can have a battery that chages with 10 watts over an hour and dischage 100 watts in 2 seconds. with your calculation, it would have an efficency of 1000% and thats not the case. in reality the battery charges with 10 W over 1 hour (60 min -> 3.600 s). so it saves 36.000 WS. it discharges 100 W over 2 seconds so 200 WS. so the real effiency would be ~5,5% and not 1000%
I understand what you mean👍 and the power monitor module in combination with the Arduino Nano measured the voltage, current and time for both charging and discharging. So the wattage is, as you say, the full and actual consumption and power generated by this setup👌
@@ConceptCraftedCreations Are you saying that it took 860Wh to charge this battery?
If so, this result seems unlikely because the video shows that charging takes less than a minute, which means that in order to store such energy in such a time, the engines should have a power over 50kW. You must have a miscalculation somewhere, maybe this capacity is 860mWh?
@@ConceptCraftedCreations Yep it's pretty easy to understand all the so-called people using precise exact overthinking terminology just don't understand it. you measured what it takes to charge and what it discharges.
This
Batteries are a hell of a drug
To clearify how i got to the result you see in the video:
To charge: ~12.08V x ~1.62A x 43.709 seconds = 860,64 Watt
After a discharge: ~9.42V x ~1.15A x 57.993 seconds = 628,24 Watt
All value's are measured by the Arduino Nano in combination with the INA3221 Power module.
pretty cool. I'm just an armchair enthusiast of energy storage but the thought experiments are fun. For a compact energy storage method with no chemical danger, no real degradation and easily serviceable parts, I think this is a pretty cool experiment. I think scaled up with some refined tolerances could absolutely get the efficiency up. The danger, of course, is large vacuum chambers, but this would be interesting to see something like this on houses. It makes me wonder if there is any potential in simple having a large vacuum chamber with a regular vacuum pump and then a valve to switch it over to a fan generator.
Pretty good results, if you improve the generators by having dedicated generators that go on with a clutch as the motors detach with another clutch the efficiency should go up by a lot and it probably will make your battery even market viable
I work with equipment that is very sensitive to atmospheric pressure changes and I will say that this energy storage is extremely interesting. Especially, in climates that have massive ambient pressure spikes.
imagine if this is done under water. or lik ea mile deep in the ocean. the force of the water on the equipment would be a lot higher
I work in an industry where i get to witness how quickly seals fail
I like it, and I think that cost and size are more important than efficiency, because these are intended as solar powered batteries. This idea doesn't require an artificial lake in mountains (die we niet hebben in Nederland) or holes in the earth. If the batteries don't get you through the night, you just need more of them. So great job!
I think this is the more important take away in that you have a small compact design with a few cheap consumables needed for maintenance. (mainly seals)
Where I live, the area has been powered by pump storage supported by various power plants since the 1980s. About 15-20 years ago though, they started putting in wind turbines. Many people were critical and still are. I think it's really cool though. In the time since they started installing the turbines, they've put enough in that the pump storage is entirely powered by wind energy and it's really cool to live 20 miles away from something like that. I feel fortunate to have such clean energy generation in my area and if I go past that, it's just a giant lake all the way to Wisconsin so the air here is pretty clean
pumped storage is such an interesting and useful idea! its so simple yet effective.
it helps combat the unrealiability and demand problems of green energy by allowing the energy to be stored and made more stable!
Fantastic! The advantage to keep in mind is it's more compact than a gravity battery. Though you won't get the same efficiency per unit, you do get more capacity per volume. If you charge it with earth and solar powered Sterling engines and use flywheels you'll only have maintenance cost. I love it!
Very cool project. The design gets cool points. A few suggestions:
To cut down on frictional losses, 1 vacuum chamber with a diameter optimized for ideal torque. And something to better stabilize the plungers as it looks like they are crooked in their cylinders which will reduce efficiency.
Really cool project! I think friction is your big problem. First of all. The pistons are not staying vertical as they are pulled slightly off axis by the timing belt. I'd make the pistons have skirts made of Teflon to keep them vertical. I'd also consider trying different seals on the pistons to see if there is anything capable of producing a vacuum but causing less friction. Finally, the big move is to reduce the number of pistons by increasing piston diameter. When you double the diameter, you double the friction surface, but you quadruple the displaced volume. 8 pistons looked cool. But it made the friction problem worse. It's why you don't see many small displacement, high cylinder count engines like a 2 liter V8.
Oh, I see Robert Murray-Smith all OVER this idea if he ever comes back to RUclips. RIP Patti Smith.
I miss him tbh 😢
I hope he's doing ok
@@atrumluminarium I miss him too 😭
Loosing your significant other is a tremendous blow, and then there's ALL the practical things on top
Give it time, they say. I'll give him all the time he needs - and yes, I'm sure he'll have some wonderful insights on this amazing idea
oh no i didnt know that.. how sad :(
Awww. I'm sad now.
Been wondering what happened. Poor guy.
Vacuum batteries, what a neat idea. Awesome work, man, I hope your channel keeps growing.
Thanks mate! Appreciate it👌
I wonder what is the energy density, and cost per storage for such a system as those would be the main considerations for its competitors.
Make it a sealed large diameter diaphragm to minimize the losses and maximize the space efficiency
That should also largely increase the lifespan… those friction seals will not be around long, and the habit of leaking will rub off fast…
That thought had occurred to me when I was contemplating the possibilities of pumping water with just gas pressure. It never would have worked because of the weight of water being what it is, but a diaphragm allows for the gas side to be completely sealed and to use a more volatile liquid to get the most range of pressures possible.
I was glad to see some more experimenting done with this concept. I started buying screen door closers for my experiments, unfortunately I never made it to any prototyping
Great Idea! One question: In the efficiency calclulation you wrote "watts" which is power, not energy (would be watthours). Were the motors consuming 860 Watt during charing and generating 628 Watt during discharging? If yes, how long does it take to charge and discharge the "battery"? - Watt * Seconds / 3600 = Watthour. Stored energy of about 700 Watthour seems to much... Thank you for your answer and keep your great work up and the RUclips channel up!
Was about to ask this as well, how long does it discharge vs charge. Having something put out 600 watts is nice an all but if it only lasts for a few seconds, that's not really much usable power
He said tripple before so i’m assuming 1:3
Hrm, no response yet. Not a good sign.
exactly that.
Must be ~4Wh on output. ~4.5 second for ~4cm of tube...
I think the best part in vacuum storage over pressure storage is the fact, that it provides linear force and can be generated and used very fast. I could see it as a kind of capacitor. Used when an excess of Mechanical energy is there that needs to be stored and then used almost instantaneous afterward, so airtightness isn't as big of a problem. I had to think of one video from Tom Scott, where he uses a Motion wheel to transfer the momentum of a bike to use it for accelerating afterward. This seems like a pretty good use case especially because it is limited energy that can be converted, and it doesn't bring any access weight with it like the flywheel.
You are absolutely right! And the way you describe it is also the best way to look at it, I think👌
You can get a linear force using preassure storage as well, you just ned a preassure regulator.
great work so far! you should also graph, lifespan, energy density, cost per kilowatt of storage and then you would have a better idea of wear your headed, its worth noting that a prototype is probably significantly worse than it could be with upgrades
Genuinely surprised at the figures you pull out at the end. If you increase the diameter of one cylinder, you'll get proportionally less friction from the sides of the rubber gasket and you can simplify the device. Doubling the radius of the cylinder doubles the circumference but quadruples the surface area.You might also be able to put the tops of the cylinders under passive pressure to increase the force on a single piston, or put the whole device under pressure. How good are the gaskets at holding the pressure? Is there any loss over time from gasses moving from one side to the other? Can probably improve that by increasing the molecular mass of the gas that's exerting the pressure. Maybe sulphur hexaflouride? Argon might be cheaper and is definitely safer, but probably not as good. I'd also try putting bearings on the support for the gasket... how do I explain this... since the gasket needs to be kept straight, the piece the gasket is attached to is rubbing along the walls of the tube so, if you put bearings between the gasket holding thing and the tube, you'll reduce friction.
12:22 I don't know if the joke was intential but your got a chuckle out of me.
Would submerging the tubes underwater or in a pressurized air tank increase the total resistance it has to overcome thus you could increase the gear ratio to also increase run time?
A giant vacuum battery in the bottom of the ocean could theoretically store a huge amount of power... Maintenance would be a PitA though
@@raphaelsampaio7172 It would also strongly want to float
@@romanp.5236 technically it wouldnt, since its a vaccum, so theres no buoncy issue.(i think)
I couldn’t stop thinking of using diaphragms for vacuum formation instead of pistons the entire time I was watching the video. It would eliminate leakage and friction.
friction, leakage and maintanance for this battery would be to high to be practical, But idea with diaphragms would reduce those. You could build closed sealed system with less wear. But! you can create vacum, how dou you want to turn it back to mechanical energy? they won't vibrate by constant vacum and i think mechanical solution to turn the vacum back to mechanical would add the problems back that you solved by using diaphragms :)
@@smoketatum6730One way valves and a crankshaft?
@@Alkatross yep, and thats what i ment, by adding complexity You are adding more maintanance and leakage possibilities, so You are back to Point 1
I'm just watching half of the video and I'm already amazed at the experimental setup you implemented for each phase. Kudos to you!
BTW, which model are these motors you're using? Thanks!
Jij bent echt een maker terwijl ik vaak niet weet waar ik beginnen moet om iets om te zetten in een product of test. Ik heb nog wel wat ideeën voor je om te maken!
Ik sta altijd open voor nieuwe ideeen!🤓 Mocht je ze willen delen kan je mn e-mail adres vinden bij de kanaaldetails op de kanaalpagina👌
Awesome channel! loved the video. my only tip is regarding the video style: i would like to see the batery being used to power something in the end right before the numbers of efficiency, it helps with the story-telling if you have a "final results"/resolution part in the final edit :) keep the good work!
Thanks for the feedback👌 I will definetly keep that in mind for the next video!
I think everybody here is missing the point thats its a proof of concept, some of the maths might not be exact or perfect but im sure none the less he had a alot of fun building and designing this project, learnt a bunch of things on the way. C'mon ppl his not saying he is making zero point energy just having fun expermenting with alternative battery types. Im looking forward to a MkII.. 😊
Yes, exactly what you say is indeed what I first thought when I saw all those comments coming in😄. But the other side of it is that it does spark fun discussions🤓 Thanks for your support! Appreciate it!👌
@@ConceptCraftedCreations I am glad I found you video in the haystack. Subscribed before even watching the whole video. Ty
As a POC it's interesting, and it's going to spark some thought, but it's got several major challenges that will make it less than ideal for implementation. It's part of the reason the Hyperloop concept was doomed to failure after over a century of pneumatic pressurized tube passenger rail trials.
A proof of concept is supposed to show something as being feasible, this contraption is just not feasible. The friction, multiple layers of energy loss, air leaked and wear, there's just so much worse about this than a spring, compressed air storage, or even just a weight on a very rope.
"Vacuum energy" sounds somewhat like Stargate technology, it even looks a bit like Zero Point Module ;)
If only it could produce power on par with one of their zero point muduels, that would be amazing and terrifying.
Commenting so you get recommended by RUclips.
I think it worked because it got recommended to me lol. Worth it.
it worked buddy 🎉
Worked
I see I am not the only one that was recommended the video lol. Thank you for your service o7
Worked thx
Great attempt. One important thing to note is that when a load is connected to the motor the force required to to overcome inertia will be significantly more than when no load is connected. You measured the force required with no load on the motor.
Lekker man, goede video en erg interessant concept. Misschien is het nog interessant om te meten hoeveel energie je verliest als je het ding een paar uur of dagen opgeladen laat staan. Maar goed bezig, ga zo door!
Nothing is a waste of time if you collect valuable data 😊
Also just a crazy idea for a gravity battery that could work is turn a whole parking garage into a gravity battery. The roof can be all solar panels. It should be loaded like a spiral column with a car elevator in the middle to load and unload cars. It will double as a space saver too.
You'd have to park by day and unpark at night
Given the easy access to the used materials and the easy way to construct it: Yes please for a bigger version! This has so many possibilities and just the reduced need of special materials makes this a very cost effective way. I love your creative engineering!
Thank you for your compliment👌 and I'm glad you enjoyed the video!
This result has made me itch to start working on a large version.. So there is a good chance that this will happen in the future!🤓
@@ConceptCraftedCreations I am an engineer myself and too many of our projects are only looking at high-end solutions, that cost a fortune to build. If we really want to enable others with less financial abilities to be part of this transition, we desperately need solutions like the ones you show.
That's one of the main reasons i wanted to try this approach. To get new results, you sometimes have to try new things! And i always think that if you don't try, you won't know! Right?
Awesome project! I was thinking about making a gravity battery for the house and was thinking, that it would take heavy blocks or water, but i didn't even think about using vacuum for energy storage!!!
I think its really important to talk about energy density, cost per joule, dependancy on rare/unstastainable materials, easy of manufacture, room for inovatiom, scalabilty etc when talking a novel energy storage technique. If this is a standout in just 1 area, then there's a great niche for this
No offense, but measuring energy in watts is a bit cursed 💀
It's not measured in Watts. He said Watts, he meant Joules.
We're all going to be fine 😂
It's fine. He's measuring the power in and out. Energy is going to have a linear relationship to that. It's the same as when people talk about their weight in kg. We understand what it means.
@@JohnDoe-ej3wp Yes and no. Depends if he is measuring stuff for the same duration. But yeah, it's just a physics thing. He is actually measuring Joules, just said it was watts
Its the most efficient way if doing it. Wdym lmao.
You cant find current without both volts and amps. You can convert your current to whatever you want, 1000000 volts or 3 volts. The only important part is the wattage. Its just amps X volts.
@@TheAshYam Not really. The important part here was Joules because he wanted to know the efficiency of the battery. Watts is useful to calculate Joules. The main issue was the nomenclature because he ended up calculating Joules, but called them watts
Gravity storage.....IN a vacuum? Anyone else intrigued by this idea?
Neat but dude come on, just use a spring! ... it's basically already working as one and you are just complicating it with all those rubber seals that will need lubrication and still fail in a couple of thousand cycles. Using a steel spring would be so simple and just as effective.
That’s not as fun
Sure, but it feels scaling this up would be easier than mass producing giant size springs.
But then again I have no clue about the spring industry :D so it would be a question of price and availability
I have always been interested in gravity energy storage. This was a fascinating concept and design.
At 73% and being a prototype only.. there is always a lot of room for improvement. Especially with a team of engineers.
On that note. This holds good potential.
Thank you for the video!
Capacity is also as important as efficiency. Same volume Li ion has far more higher capacity for instance. you should compare it too
RUclipsrs are solving world problems
Are you Dutch?
Dacht het zelfde 😂 lekker Nederlands ge-Engelst
@@nefarious_blue Ja.
@matthewgriffiths9642 Fr.
If there is a place that has a change in pressure, perhaps movement between the two places could make this viable. Like a space elevator. The change in pressure between the two places could charge a battery with this concept. Kinda like temperature difference in the ocean but too much of that could have adverse effects on the ecosystem.
I was going to point out that friction and the strength of the tubes are your biggest efficiency obstacles (mentioned in comments but not the video). Higher quality and tougher materials could improve the numbers but this video still did a great job explaining the concept. Gotta withstand the pressure and friction.
No worries about the efficiency. For a prototype that could benefit from scaling and optimization, 73% is remarkable! Very nice concept. If you make a larger model, I think the efficiency will improve because the losses due to friction will be relatively smaller. All good wishes.
To compare you should also consider:
-volume density
-weight density
-cost
-safety
I'd love to see a full ocmparison with standard storage (batteries, mechanical storage, etc)
The problem with storing energy in vacuum is buckling instability in the storage vessel due to compressive forces acting on thin shells. It is why vacuum tanks end up being thick and bulky with high embodied energy. A concrete or even rammed earth vac tank may be the way to go for the rough vacuum needed for energy storage. The energy storage density is low, so the materials used to make the tank need to be energy cheap.
0:47 They've been trying to sort something like that out, based on that gravity and weight principle, in large scale to work with hydrogen fuel cells to store excess energy from wind turbines during the day and then to use the stored energy at night. Cool stuff.
Brilliant! Manufacturing this in large scale wouldn't generate toxic waste and if there was structural failure, it wouldn't explode, burn, or collapse, but just slurp up air.😃
Reduce the friction when the belt tightens. When it releases it will bind resulting in power loss do to frictional force.
Alternator concept would apply greatly here which is theoretically what you are doing.
Id love to be of help if any.
I spoke to my stepdad about this when before now I’m seeing it and the fact it works and he doubted me, so i never birthed it into fruition like you did.
Good job man! You completed something i have always thought about
7:28 this much tension & gearing will consume energy. Reduce overall efficiency.
I would be interested in volumetric and mass energy density of this system. Did you measure them? Is this viable for mobile applications or just for stationary use?
This is a remarkable idea, smaller and safer than some others I’ve been pondering. If a flywheel breaks, it’s a very bad day for everyone. Maybe even the neighbors. But if this breaks it will be pretty loud but not all that dangerous.
I’d like to see one scaled up to the size of a large hot water heater. Something that could sit in the corner of a basement. In conjunction with rooftop solar and a moderate home backup battery system it could be pretty amazing.
You could probably greatly improve it by reducing friction.
You might be able to do this in a few ways. My first couple suggestions are these:
1: Add braces between the tubes so that they do not flex side-to-side under pressure. If the tube bends, then the piston ends up being forced through a curve rather than a straight line. This creates unnecessary tension and friction.
2: For the same reason as the horizontal braces between the tubes, you could consider placing vertical braces between the base and top of your contraption. These would remove a lot of the downward stress, which is currently being applied directly to the vacuum tubes, causing them to flex.
3: A slight bit of oil to lubricate the seals at the end of the piston would probably go a long way in reducing friction.
Those are just the first things that come to mind, though. I enjoyed watching. This is a very interesting concept.
The power of RUclips. A very good design and I appreciate the time and effort in it.
Glad I found your channel. I look forward to watching other people teach things my curiosity lives on. Awesome job and best luck to your channel. Look forward to seeing everything you have to share!
There's a few things I think It would be worth testing:
- Scaling up from 8 to 16 tubes and seeing if you get double or more than double the energy storage
- longevity testing - how many charge/discharge cycles can you get before the rubber seals wear out and then you can calculate the ongoing cost to maintain this type of battery
- there are applications where longevity and weight matter more than size
- if this design can be made in a manner that a few pieces of rubber can be swapped out in an hour for n thousand charge/discharge cycles then it could be quite cost effective against chemical batteries in high cycle applications
Man!! This guy really thinks outside the box, I love it!!
Cool product, while the energy return % is fine it’s a duty cycle and cost questions now.
Great product and video, thanks for sharing.
Probably the coolest novel probably energy storage idea I’ve seen in a long while! Get that patent quick! If it truly rivals hydro storage then you have a much smaller more eco friendly power storage option which our future clearly needs! Definitely say try a larger scale design and see how the numbers compare with scale.
10:32 judging by those bubbles it seems like your system is leaking which probably has an effect on the efficiency calculation
no leaking, just boiling of water due to low pressure.
Nice concept, I already detected some advantages of this concept:
- It is easy to scale up the capacity by using bigger diameter for pistons or more pistons. While the other concepts are harder to scale up. The scalability is of power 2 order. i.e twice the diameter gathers 4 times more force from the atmosphere.
- There is probably a way to enhance efficiency: using bigger diameter pistons and reducing the piston course (displacement), this may reduce the friction. Not sure, this needs some computation and tests. With a bigger diameter and lesser length we have a bigger surface of friction but acting on less length. The friction is caused by the normal force acting on the cylinder by the deformation of the joint, will this force be bigger or lesser with a bigger diameter?
Wait now take this an make it powered from the atmosphere pressure changes. Place the pistons in the middle of the stroke on a day of natural air pressure. On days when storms move in the atmosphere pressure will drop this causing piston movement and thus energy.
As you noted this is similar to pumped hydro. You could achieve the same with moving water and its less likely to leak as water seals are easier to maintain than air seals.
But here is an idea you can't do with pumped hydro. Air pressure is always changing. If something is changing we can harvest energy when it moves from a high stored energy to a low. Think about building a pressure vessel with one way valve. When the air pressure goes up it overcomes the valve and equalizes the pressure inside the vessel. When the air pressure goes down you can harvest the pressure from vessel as you allow it to escape. The interesting thing is that this can happen passively and you can sale the vessel to be very large capturing more energy.
As for using old mineshafts for energy storage with weights mentioned in the start, I really have my doubts about the viability of that from a practical standpoint.
I work in the mining industry as a geologist and maintaining an abandoned mine is very expensive and a huge liability. Underground mines are almost always below the water table, so there needs to be constant pumping and maintenance done to prevent flooding. The ventilation would also need to be maintained to prevent explosive gas buildups. Any unsealed areas could leech more toxic materials into the mine water. And mines are naturally unstable, they will collapse eventually.
Great and interested experiment. I wish I hade skill and patience like you. Thank you again
One thing you should consider in addition to efficiency is the size of the system. How big would a full-scale machine need to be to store and then release the same amount of energy as that of a pumped hydro for instance? Unlike compressed air batteries, the pressure difference between the inside and the outside is not higher than one atmosphere, so to generate more energy you must build a bigger machine (i.e. a bigger vacuum volume). However, with compressed air, you can increase stored air pressure by using stronger materials or thicker metal without much increasing the machine's size.
in the very last shot of the machine working, I'm seeing air bubbles leaking in through the bottom seal. If that's the case then improvements on the seals would increase the efficiency. larger versions are going to suffer from crush pressure of the tubes. even if they don' implode they could bend, warp or buckle somewhat inelastically and I can only imagine that would cause problems. I'm sure you'll be able to account for that but be sure to do the calculations on material strength if you go bigger. implosion can be dangerous. I love this. Great video. more, more, more.
Heeey. Dat daar is een dutch accent😂 fijne video
I like the way you think! I subscribed immediately. I would call this a pneumatic battery, or maybe a vacuum battery. Well done! For our North American friends, 1910g = 4.2 pounds.
You should try testing this with a large capacity commercial air compressor. That's honestly the only way you might be able to test this at a larger scale, but you won't be able to use the same motor that compressed or decompressed the air. I am not sure was expecting in terms of efficiency before you got your results, but it would make sense that it would be closer to the same as hydro, because it kind of works under a very similar principal because air is technically considered under fluid mechanics, but this is technically more like a spring so it's not quite the same as the type of fluid mechanics we were comparing it to earlier. I think with a larger scale with better seals, you might be able to get even more efficiency out of it.
It’s an interesting concept. The main problem is that it’s dependent on the pressure of the atmosphere. I would suggest doing it under water for wave power or sea wind farms or adding a weight to the plunger and combining it with a gravity battery.
I am no engineer, but impressive to me.
Few potential improvements.
1) Belts are less efficient than chains. Maybe, the linear motion required could be achieved with toothed rods and gears.
2) larger diameter tubes and less of them would be less surface area on seals.
3) could be worth seeing what % vacuum achieves the greatest efficiency. Maybe only charging to 50% is more efficient than to 100% (or some value other than 100%).
As you have a prototype, could be worth exploring patents in this area and seeing if you could patent it. It being lower efficiency than batteries which are the only other worthwhile home storage solution (maybe gyro too) is fine as this is much simpler to build and doesn't require rare earth metals (well... magnets in the motors but still).
A beautifully executed experiment with interesting results. I fear a full sized version might prove that making a vacuum vessel large enough, yet strong enough to avoid collapse might prove too difficult
Excellent idea. Ya know there are a lot of inventions with or without patens that are out there that didn't work at the time they were created, but they really need to be revisited, because now we have the technology and the ability to take some of these ideas to the next level. There are numerous creations just waiting for the right person to come along and use them.
Amazingly good results for this system. In theory, when you lowered the pressure in the cylinder, the temperature decreased. This temperature gradient would cause the air inside the cylinder to absorb energy from the ambient air outside the cylinder. This obviously makes the system less efficient. I wonder if insulting the cylinders would provide even greater efficiency? Very interesting idea that you have developed.
is that a serpentine belt i saw? this is a cool project man! didn't expect to see a powerful vacuum seal today but here i am lol.
Considering the ideal gas law: PV = nRT
I'd love to see you incorporate an efficient thermal aspect to this design to see if you can further improve the efficiency of storage / discharge.
I don't know if anyone's said this, but if you held it inside a higher pressure chamber, would it store more energy?
This should definitely be invested in and upscale if not for future use than for experimental purposes testing to see what parts wear out, how long it takes each part to wear out, what caused the malfunction, and then what it would cost to make the repair and how much time it would consume. I think this is worth further investigation.
if you were thinking about long-term, as one who uses an AeroPress to make coffee and had to replace their seal recently, one potential downside I foresee is the wear/tear on rubber. Not an big issue in your prototype, but certainly an issue if scaled to industrial size.
Really impressed you get something over 50% efficiency on this small scale
Very cool. Without running the math - my intuition is that energy density will be the main problem with this. 1 bar of pressure is going to have a pretty low hard density limit - making it impractical. If to power a house for a day you need more volume than the house then the problems of scaling become obvious in a way it isn't on a model.
Please forgive me if it is nonsense, but I have a few ideas:
Would compressing air instead of creating a vacuum work as well / would it be less or more efficient?
Could you increase the efficiency if you minimize friction beetween the tubes and seals?
Great project, really. I am not a professional in this area, but with stronger materials etc. this seems like it has potential. Cool.
Neat Idea, I like the fact it's compact, easy to make (relatively), and doesn't use toxic chemicals. The only major "con" would be the maintenance on storing the energy long term. Holding vacuum is a active process and it will leak over time, which will require energy to maintain. A gravity battery like stored hydro, is passive as you only have to pump the water once. It's more efficient, but is not as compact, and requires a large head span. Could you not swap out the vacuum with an 80kg weight and simply do a linear generator? or what about using a spring with a resistance of 80kg?
I my self see some improvements they can be made,
1 some type of thin lubricant would be great.
2 because of the high friction the motors are just working too hard to pull all simotanusly, make a mechanical configuration that will do it two or one at the time, so basically you fight against friction.
3 most important, if you have more tubes you will have more power stored so it will potentially heighten the efficiency.
4 siquentional vacuum, and sinquensional pressure
5 I don’t know for sure if a vacuum pump would help for another project :)