Added: 3 years ago
From: barumman
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  • Nice video. Only one part I don't like is measuring of the output power. Lamps has no fixed resistance - as it heats up, resistance increases. So, it will be better to use voltage AND current measurements instead to get exact measurement of the output power.

    I bet you will find your generator is more efficient than your math show. What has poor efficiency is this drill (waste heat, cooler fan, bearings...).

  • Excellent measurement techniques! Would twin cylinders (or multiple cylinders for that matter) help with efficiency?

  • Very nice build. I particularly like the heater tubes and burner housing. The housing looks hydroformed. One of the key features of the rhombic drive is the theoretical perfect balance. Meijer used to put a nickel coin on the machines during demontrations. He would set the coin on edge and show that it didn't fall over while the engine was running. A friend once commented that the balance was amazing, he had seen a demo where the engine seized a bearing and the nickel didn't fall.

  • Does the size or displacement make the engine more or less efficient?

  • @moffett8 Hi , I'm not sure, small engines have a higher mechanical friction loss while the larger ones have a problem of getting the heat into the centre of the engine. I hope that makes sense, Cyril

  • Barumman, I'd be very interested to see what percent power increase you get by pressurizing with helium or hydrogen. Thanks for letting see your fine work. I'm very impressed by the level of skill needed to make the engine. How did you connect the tubes on the head? Beautiful work!

  • @talon0863 Hi, Thanks for the kind comments,The tubes are high temperature silver soldered, as for using helium I don't think it would stay in the engine very long I expect it would leak through all the joints.

    Best wishes, Cyril

  • Barumman , Hi  I take it your answer to be yes! But not on a small model as that

    What say a eng. 10x bigger - built out of the best SS,Titanium,etc., w/ a flywheel

    heavy enough to retain torque - coupled to a gearbox to increase output RPM to

    a direct driveshaft turning a power plant generator. And harnessing earths Geo

    Thermo heat for power (Superheated Steam) ?

  • @rrfields65 Pass :)

  • Barumman, would the power increase-if say you heated the heat tubes from a

    heat source just under it's melt point and cooled the jacket with liquid nitrogen?

  • @rrfields65 Hi, I expect it would fly apart ! Best wishes, Cyril

  • Great vids :). I am assuming that the generator isn't using neo magnets if you made it 12 ood years ago. I love the way you test for effiency to, i must try that out on my proto type alternator, That's pure clean maths at work.. Please have a quick look at my vid, even better I would love you to make it with your tooling skills. maybe you could give my alternator a guestimate efficicy rating. Thanks for the inspiration and vids

  • HE'S USING YOUR KITCHEN SCALES!

  • This has been very interesting to follow so far. And to make a Stirling with almost one watt per cc means theres hope for the future of power generation.

  • good job men.i realy happy we can make power at home i will try make that at my house.again thankyou.

  • good job men.i realy happy we can make power at home i will try make that at my house.again thankyou.

  • Nicely done, the engine looks really slick!!!

    Although the efficiency of the generator is not top notch, I don't think it really matters for this example, because I'ts a transversal problem to all electric generators.

    I am more keen in knowing how much gas is burned to get out those 60W/h from the engine, do you have any data on this?

  • @paulomiguelmartins  Thanks for the comments, Sorry I have not made any fuel consumption measurements

  • Be sure to post them if you ever get the chance!

    Another thing, you should be careful when operating compressed oxygen mixtures and lubricants in the same enclosure, otherwise you can get some pretty nice fireworks!!

  • excellent vids and workmanship!...obviously your mastermind mind is not stricken with attention deficit!...lol....my attention challanged, usually semi intoxicated mastermind couldn't come near these achievements! even with mothers permission to use her kitchen scale!..lol. i'm curious, could you also use the power input of the drill - power loss of the drill motor to find efficiency of the generator? what is the accuracy of the formula in estimating the efficiency? thanks

  • @dirtydogvideo  Hi, the formula for calculating the efficiency was obtained from a reference book so I am assuming that it is correct, I think that measuring the power input to the drill motor would introduce more errors.

  • Thank you for sharing these videos, amazing!!!

  • Good thinking, :)

  • This project is awesome. an idea: If you intend the engine to run off gas all the time then you could route the fuel through coils in place of the liquid coolant..don't know if that's efficient but my theory is that the gas is cooled as it decompresses, absorbs heat thereby cooling the cylinder and preheating the gas for more efficient burning, all without a pump or a fan.

  • @hibraisil I've never built an engine but I do blow glass and I've seen my propane cylinder get pretty cold, frosty even, at high output.

  • Fantastic work. I bet with some tinkering you could more than double your output. Thank you for posting these.

  • He's using you kitchen scales!!

  • @zackshalac

    Shuuuu ! you will get me divorced. Best wishes, Cyril

  • Thank you very much for your videos of your engine!

    Great job building and getting it to work, and excellent job testing and showing the efficiency of the generator/motor.

    Live long and prosper.

  • Incredible work! Congratulations!

    This is beyond smart; you are brilliant.

    Please demonstrate your works to junior and high school students, and even engineering students to inspire them. The world needs these technologies developed into mature products.

  • I'm curious as to whether methane would work well as a working fluid. It's safer than hydrogen anyway; you can smell it if there is a leak (assuming mercaptan has been added), and it only ignites under a narrow range of concentrations. However, I don't know what would happen if the engine discharged all of the methane very rapidly.

  • you can up the CC's of your engine by increasing the vaccume of the displacement piston by lowering the temperature of the power side I know a way to get -60 F atmosphere that would double your horsepower , we can do this without any trouble what so ever , I still say my cooling system and your motor would make stirling solar profitable

  • Nice beta. Is your heater made of 316 stainless steel? Have you done a computer analysis of your engines gas circuit? I am building a larger beta engine at the moment but I haven' t quite figured out the rhombic drive geometry.

    Really really nice work

  • @idkleine  Sorry I have no idea as to what grade of stainless it is.

    I havn't done any analysis as I am a cut it and try it man, thanks fpr the interest :)

  • could you measure the efficiency between air and hydrogen? i would like to see physical different between air and hydrogens heat conduction properties

  • I would probably blow myself up, I will give that a miss for now but I may try Helium some time in the future.  :)

  • Nice work! Also, good to see someone trying to build something more than a model. And knows some science.

  • Thank you for the videos, veryinteresting to an engineer. You should be proud of what you have achieved.

  • Beautiful Machining very elegant machine.

  • Have you tried building yourself a magneto type generator? Im not sure if that would be more efficient but i would think it would be worth a shot. The more i think about it, the more it sounds like what orkneyak is saying.

  • Hi there,

    A lovely peice of engineering thank you for sharing. I was thinking about your efficency problem. Could you use the fly wheel of your engine to form a rotor of a brushless type generator directly and do away wuth the drive belt, etc, or would the resistance cause the engine to stall?

  • Yes I expect a direct drive generator would be more efficiant .

    I was hoping to source a bicycle hub motor which I think would be ideal, as yet no success,Thanks for all the feedback.

    :):):)

  • Ok. I think I misunderstood this part five test and I realized you are calculating the electrical generator efficiency instead of the Stirling engine efficiency. Am I right? Have you calculated the efficiency of your Stirling engine? Thanks.

  • Ive been checking out experimental diesel engines energy efficiency and according to Wikipedia, the most efficient diesel engine known by the author of that article stands for 54.4 %. This video shows a 57.17 %, which is higher efficiency than diesel engines. Also, on Keneth Wark Thermodynamics, on page 770 (Spanish version), says Stirling Cicle theoretically equals Carnot efficiency, so great experiment for anyone interested in thermodynamics and more efficient engines. Thanks.

  • questions (if I may);

    is the rhombic gearing in an oil bath ?

    is the water jacket a simple spiral ?

    where is the regenerator, and what did you use for it ?

    could a simple lever action hand activated air pump be added to the body, on the side ? (eliminating need for air compressor) and how well does that air pressure hold ?

    might the snifting valve and the pressurization port be incorporated into a single system ?

    just a few nutty, ill-informed ideas

  • Yes the gears are in an oil bath and the water jacket is a simple spiral.

    The air leaks away after a few days.

  • how successful was your "keep the oil out of the displacement cylinder" scheme ?

  • Perhaps, with some help, you can increase the efficiency of this wonderful design. I'm curious, too about the effectiveness of the burner and about what power transfer would be most efficient and compact..

    could the generator spindle not be mounted co-axially opposite the main flywheel ?

    and might the water pumping action be taken directly from a reciprocating part of the linkage, rather than enjoying a belt drive ? I can't wait to see this thing out front of a solar dish !

  • The efficiancy of the generator is very poor at engine speed.

  • Why do you suppose that is ?

    Is there a basic difference in efficiency between linkage types and/or alpha/beta/gamma configurations ?

    Might there be ways to reduce critical friction points ? like cylinder walls or belt drives ?

    and are you (even in the back of your mind) thinking of any new stirling designs ?

  • What pains me the most is that it took 12 years for us to get a look at this! Please, sir, do not stop now.

    Best,

    Z

  • This is brilliant work .. thank you ... straight into my playlists hope you'll join us.

    Cheers,

    Red.

  • wonderful series! thank you so much

  • Thank you for your kind comments

  • Hi barumman, This has been a great series of videos. You built a fantastic engine, congratulations. I rally appreciate the real world numbers you are getting at, thank you for being so thorough. Im my opinion you do not get to add the loss though pumping coolant and the loss through the fan, these are valid costs to the engine output. This was really well done!

  • Wow! Excellent work. Best on YouTube regarding Stirling Engines. I look forward to more videos. I would love to experiment with a Stirling Engine about this size that outputs more than 50 watts. Any recommendations on where one could buy one? Or specs on making one just like yours? Thank you!

  • O man this is superb, just what I was looking 4. thanks a lott

  • Very nice work Barumman and nice to see this sorta work going on all round the world :)

  • Hi! Thanks for the video! Very interesting again :)

    The +/- 60% efficiency for the generator is comparable to a car alternator, so your calculations should be correct.

    Dont forget that the belt drive takes a few percent of power, especially because one of the pulleys is small. 10% loss is possible.

    The power of the engine then gets to around 67 Watts. Not too bad!

    Dont be embarrassed about the efficiency.. I still estimate it at around 10% at output shaft, and thats a good result!

    Richard

  • Thanks Richard.

  • Nice job Barumman.

    It is not the engine that is low efficiency, rather it is the burner.

    Easiest way perhaps to estimate overall heat into the engine would be to measure your cooling water flow and temperature rise across the engine to calculate the heat lost to cooling, add on the 60Watts mechanical and I think you would be pretty close.

    But perhaps you are already way ahead of me with soon to be posted Episode No.6?

    I can't wait. Cheers Mike.

  • I can't begin to tell you how much I appreciate your efforts. Your videos are excellent! Thanks so much for posting.

    If you can stand the embarrassment, I'd be really curious to know the answer to OleTc's question about fuel consumption. I think the result would actually speak more to the efficiency of engines in general than to your particular implementation of this one. And speaking of which, you've left very very little room for embarrassment, if any.

  • Hope I don't appear pushy, but my mind has been working with the idea of how to decide the overall efficiency of this fine stirling engine.

    Could it be done by putting the gasbottle on a weight, while the engine is running. Let engine reach the 60 watt output. Then read weight of gasbottle, let it run for 5 min and read weight again. Difference is consumption.

    If the energy in watts of the consumed gas is known??, then You know energy in / energy out and thus efficiency.

    Regs

  • I'm afraid to try that as it could be embarrassing, thanks for the suggestion.

  • Here You must consider not to embarras so to speak all other Stirling-builders that publish their engines here.

    You're not just a great craftsman, but also a fine person ;)

    Best regs

  • Another thumbs up from me. It's an absolute pleasure to watch your videos. Your work is greatly appreciated by many who do not have the time nor resources to attempt such a project.

  • Another top video. Interesting and a pleasure to watch as usual. I just love the "don't tell the wife" bit!! Interesting that your scales read negative though. Mine just re-zero.

    Cheers.Geoff.

  • Those scales are very good I have checked their accuracy and they are spot on, they are to good for the wife to use I shall have to buy her another set. :) :)

  • I get goose bumps of excitement every time I see one of your videos. Very excellent and professional work. Your videos are a joy to watch. Thanks you.

  • Exelente!!! Thanks!

  • I can only second the comments. Very well done. Scientific television at its best.

    Was the enging pushed as much, as You felt it could handle to achieve the 30 watts output from the lamps?

    Another interesting question is, what the efficiency of the motor acutally is. I don't know how, but some sort of calorimeter, to measure the used amount of heat.

    To wrap things up - hope You enjoy making these videos as much as we like to watch them.

    Thanks.

  • The engine would produce more power if I put in more heat + pressure but I like to keep the

    heat exchanger tubes below red heat as they are only silver soldered.

    Thanks for the comments,yes it is good fun.

  • The weight is made of lead and is about

    500 grams, If I had accidently short circuited the output I expect it would have done!!

  • I don't get why the weight didn't whip around the shop.

  • Very well explained. Great achievement.

  • Thank you.

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