I like the simplicity and the fact that there isn't many resources out there on it, I think that it would be a useful engine to build and experiment on, because even if you fail to produce a powerful engine, you will add data to the world about this engine.
The NASA RPC Stirling engine has been running continuously for 18 years and is showing no signs of wear, You have the complicated parts already machined from your last engine, you could reuse them with slight modifications, the addition of flat spring stacks and a linear generator made however you see fit. The wear and difficulty sealing on the piston parts of your machine largely comes from the fact that the crank causes a side load on the piston, with the design with no crank its much easier to get a low friction seal, it is also much easier to get the very high working pressure that you absolutely need for both power and efficiency when the whole engine can be sealed with no rotary shafts. If you google this you could find a diagram that could be used to make a copy which would perform well and is tried and tested. The piston seals are very important, you could try some "carbon graphite reinforced PTFE" ;-)
I investigate the free pistons engines (I think the NASA RPC is one, have to look first!?) later in this series but the most are very high tech and therefore to complex like the rhombic. The free piston engines mostly have much problems with piston alignment as far as I know. I tried carbon reinforced PTFE but the tribolocical plastic W300 I use now seems to be much better. Thanks for your comment!
Hey there! Great videos. As someone lacking tools to build those engines, I have to enjoy them vicariously through guys like you. Just a little tip as a fellow German: pronounce "Efficiency" like I-Fisch-äncy wie der Fisch.
I remember research on a gold palladium alloy as a seal/bearing material. It was somehow generating graphene from compression and local carbon sources and self lining itself with it.
This is a cool video and channel! Congratulate! What do you think about a thermoacoustic engine with displacer for the heat changing and cheap turbine generator?
Thermoacoustic Stirling engines are the next in this series... What you mean in detail with the turbine generator? Sounds nice. Thanks for your comment!
You have excellent content. Applying the KISS principle, the TLE seems to be a very good candidate for experimentation. Simple construction could allow low-cost and fast iteration of design tuning. Using DOE could reduce the total number of experiments. High speed fiberoptic pressure sensors could measure the possibility of pulse tube behavior. The piston being in the low temperature region is a real plus and the simple drive configuration (even free piston) could reduce friction losses and extend the useable life. I'm a semi-retired physicist and still like experimenting on new things. Thanks for sharing your work.
I love this channel. It would be interesting to compare dinamic sealing technologies on its own, for example, piston with ring seal vs diaphragm vs belows vs rolling seal vs ferrofluid piston etc.
Like you, i have been seeking a way to convert the abundant wood waste around my off-grid home to electricity. I was and remain quite fascinated with the elegance of the free piston sterling engine, but it might be too much of a challenge for me to make one. There are a few companies that have commercialized FPSEs, notably Baxi manufactured cogen/CHP hot water boilers for the UK market that put out about 1KwE, but these were unprofitable and pulled from the market several years ago. A canadian company, Qnergy, sells or rents FPSE generators to the oil industry for providing power and compressed air at remote well sites. For my own application, I've resigned myself to an ORC (organic rankine cycle) tuebine system, indirectly heated via biomass/thermal oil and using either a radial outflow turbine or possibly a tesla turbine. The idea being to run the cold end at the same temperature i use for my hydronics, so the heat isn't wasted.
Tengo una pregunta mi amigo, si se combina un motor stirling con un motor traga llamas de tal manera que use la misma fuente de calor, aumentaría la efiiciencia del sistema?
The pulse tube cooler is usually done at higher frequency with wave generators think speakers. This seams that the piston is just applying pressure waves down the tube at slow frequency, I would expect it to be very low power.
Since I like the stackability best, I recommend trying the TLE. If any of these show promising results, stack them until they meet your needs. If you think about doing this on regular Sterling models, it would be much more expensive and require much more maintenance. In comparison, the TLE appears to be similar to a TAE, which is undoubtedly the simplest type of sterling. However, keep in mind that the energy yield will be much lower than expected. That's why I'm thinking about stackability.
I also have the suspicion that the TLE and TAE are quite similar in many aspects. Multi-cylinder engines make many things, such as the burner, more complex, so I would prefer to build bigger. Thankd for your help
@@myengines2443 Building bigger is one option. Stacking them into a string is another. I am following the rule - if one shows quite good results and it would be to much effort to build it bigger - build smaller but more and ouple them together. Imagine one crank shaft where many of these work in parallel.
1. Route compression stroke via external tubing/piping to top of hot tube ? 2. One NRV at tube inlet and another one at hot tube outlet. Also, is this a strictly Stirling Cycle pursuit or are you open to other thermodynamic cycles as well, i.e.: Ericsson, Brayton(1st Ericsson/Joule) or even Rankine ?
@@myengines2443 Assuming generator load is a steady 500 W, and since heat source is biomass(fuel pellet) - which is near impossible to regulate. What is the arrangement to regulate engine speed ?
Really interesting channel! Just subscribed! I'm mainly commenting, so the algorithm recommends your videos to people like me :) But while I'm here, i've got a couple questions if you don't mind: 1. have you considered a Nikasil coating for your rhombic sterling project? There are companies in Germany like Barikit who will coat your cylinder and hone it for you for a reasonable price. 2. What kind of efficiency have you been able to achieve with your rhombic sterling engine during your 300W test?
I think a Nikasil coating (with an al piston ?) has to be lubricated? I haven't made efficiency tests as the engine has to run first to my satisfaction and there is still much room for improvement. Thanks for your nice comment!
@@myengines2443 If the temperature is kept under 600 C then you might consider a DLC type of coating that can be applied in you shop with acetylene in oxygen starved conditions
Lov Your work. ❤ Sorry but I think its a dead end. You can make large cheaper stirling using Your knowledge and exp. Making it affordable and efficient. Im making now one from simple and cheap compressor. Fun and complete parts. Goal is not to create any free energy. Goal is to geat ahead before photovoltaic panel when its no sun. ❤ A Lot of good work here. ❤
Your project sounds nice plz make a video and show it here, it will be interesting! Before I build a conventional Stirling engine again I want to explore all other possibilities. But I actually bought a 130mm diameter 1.4571 stainless rod for a much bigger Rhombic... Thanks for your nice comment!
@@myengines2443 check my comment under Your TMG movie. This is the future there. Nasa "free piston" is my retirement project ^_^. But now im connecting simple big barrel to compressor (like a caveman;) to make it simple fast and affordable. Somebody with Your skills should use simple arduino to control delay of running free piston... Maby ill make some video soon. Respect to You Sir.
@@TheBaconWizard For now its gamma but i will test alpha also. Ive just connected 20liter 3mm wall barrel to one cylinder with alu displacer and the second one is acting like power piston. I think it should be alpha anyway. (By the hudge temp difference and internet conclusions). So after simple power testing i will make no friction pistons on 2D springs in apha configuration.
The problem with all these low energy engine is basic thermodynamics. The best possible efficiency of a thermal engine depends on the temperature difference. If this is small your best possible efficiency will be like 5%. Further, the power of the engine depends on the heat flow. Again, if your temperature difference is small, the heat flow will be small and the engine will be weak. Both inefficient and weak.
Yes you are right. I try to use a high temperature difference with my self produced biogas and wood (or woodgas is necessary) and also will use in the final stage air preheating which will also boost efficiency. And the "lost" heat will be used to heat the home. In summer we have enough solar energy anyway.
Have you considered using hydrogen gas to heat the hot end? It's much hotter than woodgas and only produces steam as a biproduct. It can be created easily using Potassium Hydroxide and aluminum foil put through a shredder, add water and it will react releasing H2 and water vapor which will need to be condensed out. If you plan on storing H2 make sure you understand how hydrogen embrittlement works first. I'm looking into using a lead liner to help prevent it.
For large power requirements you are correct. For smaller domestic needs a turbine is probably too expensive and inefficient. It also would be necessary to develop an automatic steam boiler. This may sound daunting but there are boiler controllers available in Britain that model steam boat builders use for unattended boiler operation.
@@myengines2443 A condenser which is just a radiator will recondense the water, no need for more water in the loop, plus, any modern technology boiler will have less thana pound of water heated at any time. And with a tesla turbine, no oil is needed and you would be getting at worst 1KW and most likely 4KW with your burner setup
@@myengines2443 I like your original design, 300 watts is pretty damn good. I saw a really cool video on air bearings... I will try to find it, but perhaps that may improve maintenance.
I am not sure if steam engines are the right solution for me and an additional Stirling just for the waste heat of the steam engine will make it even more complex... But thanks for the suggestion!
Well that's your choice bias, any tech has its development or derangement as petrol contamination and excess, you forgot solar thermal vortex chimeis and solar steam that can cook, desalinate water and move any mechanical tool or appliance at the same time
I like the simplicity and the fact that there isn't many resources out there on it, I think that it would be a useful engine to build and experiment on, because even if you fail to produce a powerful engine, you will add data to the world about this engine.
But I think that the professionals will be much better...
The NASA RPC Stirling engine has been running continuously for 18 years and is showing no signs of wear, You have the complicated parts already machined from your last engine, you could reuse them with slight modifications, the addition of flat spring stacks and a linear generator made however you see fit. The wear and difficulty sealing on the piston parts of your machine largely comes from the fact that the crank causes a side load on the piston, with the design with no crank its much easier to get a low friction seal, it is also much easier to get the very high working pressure that you absolutely need for both power and efficiency when the whole engine can be sealed with no rotary shafts. If you google this you could find a diagram that could be used to make a copy which would perform well and is tried and tested. The piston seals are very important, you could try some "carbon graphite reinforced PTFE" ;-)
I investigate the free pistons engines (I think the NASA RPC is one, have to look first!?) later in this series but the most are very high tech and therefore to complex like the rhombic.
The free piston engines mostly have much problems with piston alignment as far as I know.
I tried carbon reinforced PTFE but the tribolocical plastic W300 I use now seems to be much better.
Thanks for your comment!
@@myengines2443 you have mail ?
Hey there! Great videos. As someone lacking tools to build those engines, I have to enjoy them vicariously through guys like you.
Just a little tip as a fellow German: pronounce "Efficiency" like I-Fisch-äncy wie der Fisch.
Thanks for the nice comment and the help with the Fisch!
I remember research on a gold palladium alloy as a seal/bearing material. It was somehow generating graphene from compression and local carbon sources and self lining itself with it.
That sounds very high tech but I will look at it, thanks....
This is a cool video and channel! Congratulate! What do you think about a thermoacoustic engine with displacer for the heat changing and cheap turbine generator?
Thermoacoustic Stirling engines are the next in this series...
What you mean in detail with the turbine generator? Sounds nice.
Thanks for your comment!
Off settings the drive piston from center, the way that is done on cars, might be useful.
I will look for this, thanks.
You have excellent content. Applying the KISS principle, the TLE seems to be a very good candidate for experimentation. Simple construction could allow low-cost and fast iteration of design tuning. Using DOE could reduce the total number of experiments. High speed fiberoptic pressure sensors could measure the possibility of pulse tube behavior. The piston being in the low temperature region is a real plus and the simple drive configuration (even free piston) could reduce friction losses and extend the useable life. I'm a semi-retired physicist and still like experimenting on new things. Thanks for sharing your work.
Thanks for your nice suggestions and the nice comment!
I will think about it!
This is a fascinating subject. Great videos!
Thanks!
I love this channel. It would be interesting to compare dinamic sealing technologies on its own, for example, piston with ring seal vs diaphragm vs belows vs rolling seal vs ferrofluid piston etc.
Yes, good idea!
Thanks for your nice comment!
Like you, i have been seeking a way to convert the abundant wood waste around my off-grid home to electricity. I was and remain quite fascinated with the elegance of the free piston sterling engine, but it might be too much of a challenge for me to make one.
There are a few companies that have commercialized FPSEs, notably Baxi manufactured cogen/CHP hot water boilers for the UK market that put out about 1KwE, but these were unprofitable and pulled from the market several years ago.
A canadian company, Qnergy, sells or rents FPSE generators to the oil industry for providing power and compressed air at remote well sites.
For my own application, I've resigned myself to an ORC (organic rankine cycle) tuebine system, indirectly heated via biomass/thermal oil and using either a radial outflow turbine or possibly a tesla turbine. The idea being to run the cold end at the same temperature i use for my hydronics, so the heat isn't wasted.
Tengo una pregunta mi amigo, si se combina un motor stirling con un motor traga llamas de tal manera que use la misma fuente de calor, aumentaría la efiiciencia del sistema?
I agree sounds like a pulse tube mechanism to me.
Yes, some aspects by sure but maybe it is more complicated?
The pulse tube cooler is usually done at higher frequency with wave generators think speakers. This seams that the piston is just applying pressure waves down the tube at slow frequency, I would expect it to be very low power.
Since I like the stackability best, I recommend trying the TLE. If any of these show promising results, stack them until they meet your needs. If you think about doing this on regular Sterling models, it would be much more expensive and require much more maintenance. In comparison, the TLE appears to be similar to a TAE, which is undoubtedly the simplest type of sterling. However, keep in mind that the energy yield will be much lower than expected. That's why I'm thinking about stackability.
I also have the suspicion that the TLE and TAE are quite similar in many aspects.
Multi-cylinder engines make many things, such as the burner, more complex, so I would prefer to build bigger.
Thankd for your help
@@myengines2443 Building bigger is one option. Stacking them into a string is another. I am following the rule - if one shows quite good results and it would be to much effort to build it bigger - build smaller but more and ouple them together. Imagine one crank shaft where many of these work in parallel.
1. Route compression stroke via external tubing/piping to top of hot tube ?
2. One NRV at tube inlet and another one at hot tube outlet.
Also, is this a strictly Stirling Cycle pursuit or are you open to other thermodynamic cycles as well, i.e.: Ericsson, Brayton(1st Ericsson/Joule) or even Rankine ?
Thanks for your nice suggestions I have to think about them!
Of course every cycle is interesting if it can be an effective energy producer!
@@myengines2443
Assuming generator load is a steady 500 W, and since heat source is biomass(fuel pellet) - which is near impossible to regulate.
What is the arrangement to regulate engine speed ?
I think your design and experience on the alpha configuration is excellent some minor tweaks and you will succeed.
Thanks!
Ok I found the link but it doesn't work can u please repost the links and files
There is an old link and a new one somewhere, the new should work...
Can u please send the link thx
@@myengines2443 i found it
Really interesting channel! Just subscribed! I'm mainly commenting, so the algorithm recommends your videos to people like me :) But while I'm here, i've got a couple questions if you don't mind:
1. have you considered a Nikasil coating for your rhombic sterling project? There are companies in Germany like Barikit who will coat your cylinder and hone it for you for a reasonable price.
2. What kind of efficiency have you been able to achieve with your rhombic sterling engine during your 300W test?
I think a Nikasil coating (with an al piston ?) has to be lubricated?
I haven't made efficiency tests as the engine has to run first to my satisfaction and there is still much room for improvement.
Thanks for your nice comment!
@@myengines2443 If the temperature is kept under 600 C then you might consider a DLC type of coating that can be applied in you shop with acetylene in oxygen starved conditions
So a TLE is the reverse of a pulse tube cryocooler perhaps?
Yes, maybe some aspects are the same but I still dont understand the interrelationships completely.
Its complicated...
Lov Your work. ❤
Sorry but I think its a dead end.
You can make large cheaper stirling using Your knowledge and exp. Making it affordable and efficient. Im making now one from simple and cheap compressor. Fun and complete parts.
Goal is not to create any free energy. Goal is to geat ahead before photovoltaic panel when its no sun. ❤
A Lot of good work here. ❤
So that would be an Alpha-type configuration?
Your project sounds nice plz make a video and show it here, it will be interesting!
Before I build a conventional Stirling engine again I want to explore all other possibilities.
But I actually bought a 130mm diameter 1.4571 stainless rod for a much bigger Rhombic...
Thanks for your nice comment!
@@myengines2443 check my comment under Your TMG movie. This is the future there. Nasa "free piston" is my retirement project ^_^.
But now im connecting simple big barrel to compressor (like a caveman;) to make it simple fast and affordable.
Somebody with Your skills should use simple arduino to control delay of running free piston...
Maby ill make some video soon.
Respect to You Sir.
@@christomold3142 nice!
@@TheBaconWizard For now its gamma but i will test alpha also. Ive just connected 20liter 3mm wall barrel to one cylinder with alu displacer and the second one is acting like power piston.
I think it should be alpha anyway. (By the hudge temp difference and internet conclusions). So after simple power testing i will make no friction pistons on 2D springs in apha configuration.
Cold side looks easy to 3d print. Shall we make some?
Yes maybe when the design is final, Thanks!
The problem with all these low energy engine is basic thermodynamics.
The best possible efficiency of a thermal engine depends on the temperature difference. If this is small your best possible efficiency will be like 5%. Further, the power of the engine depends on the heat flow. Again, if your temperature difference is small, the heat flow will be small and the engine will be weak. Both inefficient and weak.
Yes you are right.
I try to use a high temperature difference with my self produced biogas and wood (or woodgas is necessary) and also will use in the final stage air preheating which will also boost efficiency.
And the "lost" heat will be used to heat the home.
In summer we have enough solar energy anyway.
Have you considered using hydrogen gas to heat the hot end? It's much hotter than woodgas and only produces steam as a biproduct. It can be created easily using Potassium Hydroxide and aluminum foil put through a shredder, add water and it will react releasing H2 and water vapor which will need to be condensed out. If you plan on storing H2 make sure you understand how hydrogen embrittlement works first. I'm looking into using a lead liner to help prevent it.
I think is hard to beat steam engine/turbine.
Steam can be dangerous and is extremely maintenance intensive.
I think its hard to produce permanently so much steam?
For large power requirements you are correct. For smaller domestic needs a turbine is probably too expensive and inefficient. It also would be necessary to develop an automatic steam boiler. This may sound daunting but there are boiler controllers available in Britain that model steam boat builders use for unattended boiler operation.
@@myengines2443 A condenser which is just a radiator will recondense the water, no need for more water in the loop, plus, any modern technology boiler will have less thana pound of water heated at any time. And with a tesla turbine, no oil is needed and you would be getting at worst 1KW and most likely 4KW with your burner setup
@@myengines2443 you don't need to use water as a working fluid in a steam engine, if heat source is controllable.
A regenerator might improve efficiency and performance.
Yes, sure all engines have a regenerator, its very important!
Interesting if your goal is experimentation. But not for a practical application.
I also think that another concept will be better....
@@myengines2443 I like your original design, 300 watts is pretty damn good.
I saw a really cool video on air bearings... I will try to find it, but perhaps that may improve maintenance.
@While: 要求±10ppm 频飘太厉害会导致WiFi出问题，[泪奔]或者搬乐鑫模组的晶振和负载电容
add a heat exchange refrigeration cycle to a normal steam piston engine
I am not sure if steam engines are the right solution for me and an additional Stirling just for the waste heat of the steam engine will make it even more complex...
But thanks for the suggestion!
the point was the refrigeration cycle, to capture recirculate the waste heat, not the engine tech@@myengines2443
Glad you did it !!!!!!!! gg
Thanks!
Well that's your choice bias, any tech has its development or derangement as petrol contamination and excess, you forgot solar thermal vortex chimeis and solar steam that can cook, desalinate water and move any mechanical tool or appliance
at the same time