Author Topic: Stirling Engine energy?  (Read 2589 times)

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Offline mgscheue

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Stirling Engine energy?
« on: January 24, 2019, 03:17:28 am »
 

Offline electromotive

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Re: Stirling Engine energy?
« Reply #1 on: March 06, 2019, 03:47:09 am »
They're playing fast and loose with physics. Stirling engines produce heat through frictional losses. The only way it's going to produce *cold* is through using that Stirling engine to induce some form of evaporative cooling by compression / expansion, similar to a modern refrigeration system.
 

Offline jmelson

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Re: Stirling Engine energy?
« Reply #2 on: March 06, 2019, 07:39:47 am »
They're playing fast and loose with physics. Stirling engines produce heat through frictional losses. The only way it's going to produce *cold* is through using that Stirling engine to induce some form of evaporative cooling by compression / expansion, similar to a modern refrigeration system.
No, unlike a Carnot cycle, a Stirling cycle is fully reversible.  You can use it to extract mechanical energy from a heat source (that's a Stirling engine), or to pump heat up from a cold environment to a hotter one (that's a Stirling refrigerator).  If you had some nice heat source, like a big solar collector, you could couple two Stirling machines together to make a refrigerator, without any evaporation going on.  It is all done by changing the pressure on a gas such that heat flows in/out of the gas in certain environments.

Jon
 

Offline george80

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Re: Stirling Engine energy?
« Reply #3 on: March 06, 2019, 08:39:04 am »

While being a very interesting process and making for great little  toys, unfortunately the low power output of stirling engines means any real and worthwhile power output would take an impractically sized ( and cost) unit.
Even getting 1 Kw out of these things would take a Very large unit and either a wasteful heat source or a vey big collector of low density heat.

Either way, extremely difficult to make worth while and more importantly, cost effective.
 

Offline factory

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Re: Stirling Engine energy?
« Reply #4 on: March 06, 2019, 09:20:05 am »
Well NASA managed to get plenty of power out of a Stirling engine in a Chevrolet Celebrity;
https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19880002196.pdf

Also used in submarines and with large solar mirror/dishes for power generation.

There is more to Stirling engines than the toy ones found on ePay.

David
 

Offline DougSpindler

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Re: Stirling Engine energy?
« Reply #5 on: March 06, 2019, 03:42:55 pm »
Stirling engines were used to pump water, at an iron foundry and to compress air for church organs.  But steam was just more powerful and reliable and then along came small gas engines and electric motors.  There are a couple applications where it might work, but why when one could use an electric motor?  Far less moving parts and far more reliable.
 

Offline jmelson

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Re: Stirling Engine energy?
« Reply #6 on: March 07, 2019, 07:13:00 am »

While being a very interesting process and making for great little  toys, unfortunately the low power output of stirling engines means any real and worthwhile power output would take an impractically sized ( and cost) unit.
Even getting 1 Kw out of these things would take a Very large unit and either a wasteful heat source or a vey big collector of low density heat.

Either way, extremely difficult to make worth while and more importantly, cost effective.
Yes, Stirling machines that use atmosphere-pressure air as the working fluid are large.  But, if you use pressurized Hydrogen or Helium as the working fluid, and allow the machine to run fairly fast, they can be quite compact.  There is a Stirling solar power station in, i think, Arizona that has 50 KW Stirling engines mounted on each heliostat - by the hundreds.  They are quite compact.

Sunpower built some really cutting-edge free-piston Stirling engines in the 1970's that were very compact.  But, they didn't deal with the metallurgy properly, their engines had VERY short life.

Jon
 

Offline DougSpindler

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Re: Stirling Engine energy?
« Reply #7 on: March 07, 2019, 09:15:54 am »

While being a very interesting process and making for great little  toys, unfortunately the low power output of stirling engines means any real and worthwhile power output would take an impractically sized ( and cost) unit.
Even getting 1 Kw out of these things would take a Very large unit and either a wasteful heat source or a vey big collector of low density heat.

Either way, extremely difficult to make worth while and more importantly, cost effective.
Yes, Stirling machines that use atmosphere-pressure air as the working fluid are large.  But, if you use pressurized Hydrogen or Helium as the working fluid, and allow the machine to run fairly fast, they can be quite compact.  There is a Stirling solar power station in, i think, Arizona that has 50 KW Stirling engines mounted on each heliostat - by the hundreds.  They are quite compact.

Sunpower built some really cutting-edge free-piston Stirling engines in the 1970's that were very compact.  But, they didn't deal with the metallurgy properly, their engines had VERY short life.

Jon

Helium is a limited resource so unlikely that would be used.
Found the company in Az.

This is from 2001 or 18 years ago.  And they had been working on it for 15 years.  So after 30 years can one buy one?

Stirling Energy Systems, Phoenix, Ariz., has been developing solar dish systems for more than 15 years and is convinced the technology is "ready for mass deployment as soon as sufficient investment makes mass production possible." As with STM Power's 25 kW PowerUnit, then, the key is high-volume production to reduce costs. Stirling Energy Systems estimates the cost to produce electricity from a 1,000 MW solar dish installation would be about 6 cents/kWh. Whether this cost is accurate, and whether similar costs could be achieved in smaller installations, is uncertain.

On 29 September 2011, Stirling Energy Systems filed for Chapter 7 bankruptcy as the Stirling dish technology could not compete against the falling costs of solar photovoltaics, according to media reports.

Just as 200 years ago Stirling engines lost out to steam and electric motors it appears history repeated itself with Stirling engines once again just not being cost effective enough.
 

Online HighVoltage

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Re: Stirling Engine energy?
« Reply #8 on: March 07, 2019, 10:41:06 am »
This looks like it is not based on a "Sterling Engine" effect.

It is more like a "Thermo-Acoustic-Engine", as developed in the Los Alamos laboratories.
The only problem they did not solve, was the stack.
Otherwise this engine would probably be running already.

May be this Dutch company solved it?
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Offline george80

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Re: Stirling Engine energy?
« Reply #9 on: March 07, 2019, 07:58:18 pm »

On 29 September 2011, Stirling Energy Systems filed for Chapter 7 bankruptcy as the Stirling dish technology could not compete against the falling costs of solar photovoltaics, according to media reports.

Just as 200 years ago Stirling engines lost out to steam and electric motors it appears history repeated itself with Stirling engines once again just not being cost effective enough.

Yep, same old.  Good for toys but impractical in the real world.
Everyone is always looking for the magic bullet and to hype up the under dog.  I love all this old tech, don't get me wrong. I have a 300Kg toy in the form of a Lister Cs6/1 from the 30's but I'm not under any illusion  heavy flywheel slow speed Diesel tech could be made to break land speed records.

As far back as I can remember going to the libary after school as a kid and reading Popular Mechanics and other auto magazines I have read of hundreds of " New breakthrough engine technology that could offer new levels of efficency, performance, economy and power" .

There have been allsorts of weird and Wonderful designs and hyped up promises but none of them, bar mabe 1, the rotary, has ever made it into production. There have been a few that had a limited run like the commer knocker with opposing pistons and the Napier Deltic used in rail road engines with great success but as far as vehicles go..... Nada.... bar the rotary. Which is now dead.  Even the knocker and the deltic were just really re configurations of engines with pistons thrashing up and down the same as a Model T or even an Aveling Porter traction engine.

I think some people just have a need and desperation for something to bring hope to their lives and look forward to and will latch onto something and want so badly for it to become a success they get obsessed.  There are a lot of engine designs that could be efficent and powerful and light weight and many other things BUT, cost of production, service life, maintence requirements, emissions and a load of other factors are all even more relevant and may make a design or technology unsuitable for the mainstream whether they work or not.

I just turn off when I hear about these new engine breakthroughs now.  heard about too many that were nothing more than a PR exercise to raise money for investors to keep inventors  and researchers in a job.

When I can see the engine in a showroom sitting in a new vehicle or go down the road and buy one on it's own or in a new piece of equipment , I'll give it some credibility.

Untill such time, it's just more vaporware.

With things like sterling engines, once they are installed in working applications ( other than space which is irrelevant) they will just be interesting tech that isn't practical in the modern age.
 

Online beanflying

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Re: Stirling Engine energy?
« Reply #10 on: March 07, 2019, 08:23:19 pm »
Waffle Waffle Waffle .... With things like sterling engines, once they are installed in working applications ( other than space which is irrelevant) they will just be interesting tech that isn't practical in the modern age.

You really are full of something aren't you.  :wtf: You are being negative here and like your climate waffle anti science you spout on the modern use of Stirling Engines denying Science yet again.

Clearly the Swedish should have employed you to tell them where they went wrong on their Submarines https://en.wikipedia.org/wiki/Gotland-class_submarine before they snuck up on the Yanks in war games using your non credible device.
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Offline DougSpindler

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Re: Stirling Engine energy?
« Reply #11 on: March 08, 2019, 12:56:16 am »
According to the link you posted the Sterling engines in submarines need a supply of liquid oxygen to work and a large body of water to work.  While this might work for submarines wee are not seeing it be used in ships, cars, airplanes or in factories.  I don”t think anyone has said Sterling engines do. Not work, we are just saying there are very few applications for them.  Clearly you he need for liquid oxygen limits there application.
« Last Edit: March 08, 2019, 02:16:53 am by DougSpindler »
 

Offline jmelson

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Re: Stirling Engine energy?
« Reply #12 on: March 09, 2019, 08:11:22 am »
According to the link you posted the Sterling engines in submarines need a supply of liquid oxygen to work and a large body of water to work.  While this might work for submarines wee are not seeing it be used in ships, cars, airplanes or in factories.  I don”t think anyone has said Sterling engines do. Not work, we are just saying there are very few applications for them.  Clearly you he need for liquid oxygen limits there application.
The idea of this submarine is to run underwater with no supply from the surface.  So, if you can't suck air from the surface with a snorkel, you have to have a tank of oxidizer to burn your fuel with.  That is why they need liquid Oxygen.  It is just like a rocket, no air in outer space, so you have to carry some oxidizer in tanks.

No other Stirling engine needs this, they just need a heat source.

Jon
 

Offline DougSpindler

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Re: Stirling Engine energy?
« Reply #13 on: March 09, 2019, 08:29:36 am »
According to the link you posted the Sterling engines in submarines need a supply of liquid oxygen to work and a large body of water to work.  While this might work for submarines wee are not seeing it be used in ships, cars, airplanes or in factories.  I don”t think anyone has said Sterling engines do. Not work, we are just saying there are very few applications for them.  Clearly you he need for liquid oxygen limits there application.
The idea of this submarine is to run underwater with no supply from the surface.  So, if you can't suck air from the surface with a snorkel, you have to have a tank of oxidizer to burn your fuel with.  That is why they need liquid Oxygen.  It is just like a rocket, no air in outer space, so you have to carry some oxidizer in tanks.

No other Stirling engine needs this, they just need a heat source.

Jon

Not the way I understand it.  Seems silly to use liquid oxygen, when they could use a solid source like in airplanes for emergency breathing systems.

It was my understanding the liquid oxygen is used as a coolant for the Sterling Engine.  Maybe it is used as both an oxidizer and a coolant?

Guess what I'm not understanding is why an oxidizer is needed with a Sterling engine. 

Help me out here, what am I missing. 
 

Online beanflying

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Re: Stirling Engine energy?
« Reply #14 on: March 09, 2019, 11:27:21 am »
Some more reading here. The Sub in question has a hybrid  drive system. The Stirling Engine / Generator set still need Oxygen while submerged to Burn Fuel. The principal advantage of the Stirling design is it doesn't make anywhere near the noise of more conventional Diesel/Electric subs while submerged.

https://en.wikipedia.org/wiki/Air-independent_propulsion
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Offline george80

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Re: Stirling Engine energy?
« Reply #15 on: March 09, 2019, 12:53:35 pm »

You really are full of something aren't you.  :wtf: You are being negative here and like your climate waffle anti science you spout on the modern use of Stirling Engines denying Science yet again.

Yeah, Fk me for not just going along blindly with all the other sheeple believing every bit of crap I am told and asking questions and finding answers that do not add up to what all the other morons blindly follow.  I'm suce a trouble maker for having a mind of my own snd showing up all the bullshit that's heaped on the general public by big Biz and their Puppet Gubbermints.
I mean if you can't trust the gubbermint who can you trust Right?



Quote
Clearly the Swedish should have employed you to tell them where they went wrong on their Submarines https://en.wikipedia.org/wiki/Gotland-class_submarine before they snuck up on the Yanks in war games using your non credible device.

I stand corrected.
Sterling engines are teh be all and end all of everything we need to solve the energy Crisis.
That's why  they are planned to be in every Vehicle, aircraft, generator, water pump  and small and industrial application out there.
You read about it all the time, Sterling engines are the next big thing going to do away with ICE, electric and every other type of power plant in the next 6 months.  All forms of Motorsport and racing are getting ready to re write the recod books once sterling engines come into play.

It's not just specialist applications in the modern world they are suited for like space craft and Military applications where cost is not an issue, oh no, these things are going to be powering everything from your weed wacker to Gigawatt power stations  by Christmas.

Please forgive my confusion, I just don't know which flavour of zealot cult Koolaide I am suppose to quaff down next these days!!   :-[
 

Online beanflying

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Re: Stirling Engine energy?
« Reply #16 on: March 09, 2019, 01:15:02 pm »
Avoiding yet again the unfortunate fact that this technology works and has practical applications with your waffle. No one said it is a magic solution for all things and only you seem to think it was ever the case to allow you an apparent point to rant about.

I will leave you believing in alternate facts, non engineering and pseudo science  as you seem happy ranting and raving about it's powerful and beautiful nature and obvious truths. :-DD
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Offline Marco

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Re: Stirling Engine energy?
« Reply #17 on: March 09, 2019, 01:24:42 pm »
Quote
"It takes 100% of stack-emitted waste energy, or solar thermal ... and converts that for 40-50% [efficiency]."

It's a refrigerator which runs on a heat differential, just like say a gas powered camper fridges.
 

Offline DougSpindler

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Re: Stirling Engine energy?
« Reply #18 on: March 09, 2019, 02:33:01 pm »
Some more reading here. The Sub in question has a hybrid  drive system. The Stirling Engine / Generator set still need Oxygen while submerged to Burn Fuel. The principal advantage of the Stirling design is it doesn't make anywhere near the noise of more conventional Diesel/Electric subs while submerged.

https://en.wikipedia.org/wiki/Air-independent_propulsion

Thank you for sharing this.  Wikipedia says the liquid O2 and diesel are burned to provide power.  Not sure where the exhaust gases go.

Sterling powered subs are apparently stealthier than nuclear subs.  But that stealth comes at a high cost.  Limited range, and high cost for power.

There are defiantly one off unique applications for Sterling engines and this appears to be one of them.  I know of a couple of unique novel applications for Sterling engines.

Would it be safe to say the reason Sterling Engines are not is wide spread use is we have found other technologies over the past 150 years which are less expensive and provide far more power?

 

Offline apis

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Re: Stirling Engine energy?
« Reply #19 on: March 09, 2019, 02:44:51 pm »
The idea of this submarine is to run underwater with no supply from the surface.  So, if you can't suck air from the surface with a snorkel, you have to have a tank of oxidizer to burn your fuel with.  That is why they need liquid Oxygen.  It is just like a rocket, no air in outer space, so you have to carry some oxidizer in tanks.

No other Stirling engine needs this, they just need a heat source.

Jon
Yup. The goal is to stay under water for a long time so you need to bring with you both oxidiser and fuel. You would need that for a diesel motor as well.
 

Offline DougSpindler

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Re: Stirling Engine energy?
« Reply #20 on: March 09, 2019, 02:51:58 pm »
The idea of this submarine is to run underwater with no supply from the surface.  So, if you can't suck air from the surface with a snorkel, you have to have a tank of oxidizer to burn your fuel with.  That is why they need liquid Oxygen.  It is just like a rocket, no air in outer space, so you have to carry some oxidizer in tanks.

No other Stirling engine needs this, they just need a heat source.

Jon
Yup. The goal is to stay under water for a long time so you need to bring with you both oxidiser and fuel. You would need that for a diesel motor as well.

Correct me if wrong but would just the liquid O2 run the Sterling engine without the need to burn it?  Wouldn't the temperature differential between liquid O2 and seawater be enough to power the engine? 
 

Online beanflying

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Re: Stirling Engine energy?
« Reply #21 on: March 09, 2019, 02:55:29 pm »

There are defiantly one off unique applications for Sterling engines and this appears to be one of them.  I know of a couple of unique novel applications for Sterling engines.

Would it be safe to say the reason Sterling Engines are not is wide spread use is we have found other technologies over the past 150 years which are less expensive and provide far more power?

Being able to recharge the batteries on a sub to keep the occupants alive and not found with some motive power for a few weeks is better than limited.

The Stirling Cycle and similar technologies are likely to remain fringe for plenty of reasons but as energy costs increase then reusing excess or waste hot or cold with them start to make more sense.

Reuse of waste heat or low pressure steam energy even from existing power stations would potentially be an application but at large MW the numbers and plant size would be daunting if not cost prohibitive at present.
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Offline apis

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Re: Stirling Engine energy?
« Reply #22 on: March 09, 2019, 03:12:58 pm »
The idea of this submarine is to run underwater with no supply from the surface.  So, if you can't suck air from the surface with a snorkel, you have to have a tank of oxidizer to burn your fuel with.  That is why they need liquid Oxygen.  It is just like a rocket, no air in outer space, so you have to carry some oxidizer in tanks.

No other Stirling engine needs this, they just need a heat source.

Jon
Yup. The goal is to stay under water for a long time so you need to bring with you both oxidiser and fuel. You would need that for a diesel motor as well.

Correct me if wrong but would just the liquid O2 run the Sterling engine without the need to burn it?  Wouldn't the temperature differential between liquid O2 and seawater be enough to power the engine?
In theory at least, but it would be insignificant amount of energy compared to the chemical energy you can get by burning it.
 

Offline IanB

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Re: Stirling Engine energy?
« Reply #23 on: March 09, 2019, 03:25:45 pm »
It was my understanding the liquid oxygen is used as a coolant for the Sterling Engine.  Maybe it is used as both an oxidizer and a coolant?

Guess what I'm not understanding is why an oxidizer is needed with a Sterling engine. 

Help me out here, what am I missing. 

Correct me if wrong but would just the liquid O2 run the Sterling engine without the need to burn it?  Wouldn't the temperature differential between liquid O2 and seawater be enough to power the engine?

Not at all.  You are missing the fact that engines are energy converters. They convert a non-mechanical form of energy (heat, electricity) into mechanical energy by the equation:

  (power in) = (power out) + (losses)

The amount of power produced by vaporizing liquid oxygen is negligible compared to the amount of power available by burning a fuel.

A Sterling engine does not convert a temperature difference into power, it converts heat energy into power.

I'm not an EE--what am I doing here?
 

Online beanflying

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Re: Stirling Engine energy?
« Reply #24 on: March 09, 2019, 03:30:17 pm »
In theory at least, but it would be insignificant amount of energy compared to the chemical energy you can get by burning it.

Correct it is all about Delta T and energy density of the complete fuel available. With Air breathing engines we ignore the Oxygen as part of that equation. Using LOX alone and simply expanding it to produce gas for a piston and scavenge the waste cold in this case would be far less efficient than burning it with a fuel you are already carrying in the case of the Diesel for the Subs main engines.
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