Thoughts on this Stirling Enginge Design Appreciated

[bptdude___2569]

GH - Because the engines are in a pressured cylinder you will find that the pistons are actually being pushed up from the crank side when it is cooling / contracting. This use of heat to expand and work then transfer and cool to contract and work is what I love about Stirling engines! So simple and clever and efficient


Again, this is "hot-side-mental block".
The person who cracks the secret of a practical Stirling, among other things to be done, will have put great focus on the cold side power generation. This can not be ignored, it is half your power cycle, and Stirlings have so little to spare.

Here is your path to go:

Build your hot side as you like, but leave the heat turned off for now. Make the engine go round and round only by chlling the cold side, even if the required cooling is not cost effective, etc., for now. You do this, you will have reached an important milestone. It is perfectly acceptable in theory. When you have it even barely running, but running, with the hot side only heating to room temperature, THEN flip the switch and turn on the heat.

Then you can bask in your glory!

[bptdude___2569]

Joe - All these things have to do with the way Stirlings are heated and cooled. My ideal Stirling has no need for a regenerator because it will flash heat and flash cool the gas. As such, it hopefully will need no such wall between the two sides.

GH - I have read of this idea. But how do you do this?

There are many ways, much depends on what is your heat source and what you are using for materials. There are a number of "improvements" to the Stirling cycle I have in mind, including some I have already written about elsewhere in the web site, including flash heating/cooling, how to remove the regenerator and still have the parts of what it does that are needed somehow replaced, and timing the engine cycle similar to an internal combustion.

There are others, and when put together, I think I am evolving a new engine cycle. That would indeed be pretty cool. Every so often I wake up and understand another piece to the puzzle. I think I am getting close. And I can't give away all the secrets!



This is probably my last post for this thread, but I really am interested in how your engine comes out. Truly wishing best of luck. A machine to turn sunshine into electricity to hydrogen I know is in the future and will rock the world.

Here is a piece of trivia. Last night I read that the light buld was conceived 80 years before Thomas Edison "invented" it. At the time of Edison, there were at least 20 other people who had developed working light bulbs. Only Edison hit the right combination of a working bulb and a practical device that could be sold to the public.

- Joe


- Joe

[haselhurst]

HI Joe,

Our discussions have caused me to re-think my design.

It relates to your last comment, importance of both design / invention and simple for public to use / want.

SO I was thinking how could you make a light weight conversion kit to change a petrol / diesel motor to a Stirling engine (well 2 motors side by side - but there are lots of old motors lying around).

I have an idea to do this - I will try and build it this week - rather than my big pressurised tank version.

Will provide details and diagram once written up.

So thank you for causing my mind to think in different ways, to think more carefully about certain design aspects of the engine.
It is a great gift!

Will be in touch - Stirling thoughts!
Geoff

[bptdude___2569]

and thank you again.....

so, more hints...

I can not stress enough the importance of making sure the cold side does an equal amount of work as the hot side, an almost totally balanced push-pull system.

As Rev. Stirling made the advance of the regenerator which got his engine into the factories, my huge push will be an axuliary external second engine, that does nothing but convert extreme hot to extreme cold, like cryo level cooling. How this is done is almost a trivail exercise, well understood in industry. When using solar as a source, there is no limit to the amount of Sahara dessert to soak up sunshine, so just building a little bigger collection device should be ignored.

Also, you will probably never get a working engine from old internal combustion engines. It is just the wrong things in place.
But do not worry about this. If you can design a working machine based on a simple new cycle, selling it to Honda will take care of the cost of machining.

You have to think of it this way. And "those in real power" are not stupid to also see this. If somebody invents a cheap machine to turn sunshine into hydrogen, then what you have really invented is a perpetual running machine that makes money, literally. It would be the beginning of liquid super cooled hydrogen actually becoming the new global money unit, much as gold once was. Making it available to the whole human race will do two things:

1. upset the apple cart of all power on earth, including oil producing nations.

2. kick off a golden age of prosperity for all humans, by providing near limitless inexpensive energy. not only is what we do cheaper, but many things people usually do not think of, can be done.

Great .. OK. .. but about the engine.

The second hint ##

If you could flash heat and flash cryo cool the working gas or liquid sealed in an engine, you do not even need a hot side seperate from a cold side. Think of an engine that beats like a heart.



- Joe

[haselhurst]

Hi Joe,

Would you have a look at this engine design. It uses molten lead and pistons have attached end of metal foam that is dipped in and out of the lead to heat the air. Calculations suggest it should get the heat into working gas OK.

http://www.spaceandmotion.com/invention ... engine.htm (the same URL as before but content has changed)

I think of the petrol / diesel engine as simply a cheap set of pistons that will handle the temperatures and pressures we are using. SO it is just a matter of getting the heat transfer.
Maybe metal foam is the answer to this.

"I can not stress enough the importance of making sure the cold side does an equal amount of work as the hot side, an almost totally balanced push-pull system."

Completely agree. Both my designs should have similar properties for heating and cooling (same design on both hot and cold side).

"If you could flash heat and flash cryo cool the working gas or liquid sealed in an engine, you do not even need a hot side separate from a cold side. Think of an engine that beats like a heart."

Yes - the whole point is to quickly heat and cool gas to do work. Simple. So how do you quickly heat and cool gas? I am kinda practical so i like the idea of metal foam - very large surface area to volume!
(up to 100cm^2 per cm^3). The question is will it expell all the working gas out of the foam 5 times a second when dipped in molten metal - I will find out!!

Any thoughts!? It really helps. And I hope to have a working model by the end of this week - wish me luck!

And thanks as always for your time and mental energy.
Cosmic cheers,
Geoff Haselhurst

Ps - The world needs a bit of shaking up - free energy is a good way to do this.

[bptdude___2569]

If you have anywhere close to a working engine with even close the power you say, it would be a miricle. I went over your new design, I sorta followed your equations, and I think the machine probably is not going to even turn over!

It is heavy and requires lots of external system support. It will also be difficult to sell this thing, since it contains so much lead, which you will keep molten.

I also see you are asking for free information for a machine you are trying to patent.

I understand you are in the middle of a project and very excited, so my grand theories get skimmed over. So, let me review what happens with other commercial attempts at a power producing Stirling.

For one, most have to heat the thing so hot, they reach a limit that causes metal fatigue fairly quickly. Your design of internal heating will help, but you still will not have enough heat, even though the theory says you will. Most of the equations out there are static, in the sense they really do not watch the real dynamics of all the forces involved.

Also, the second most common method of getting power from a Stirling is to compress the gas. You do this, and continue to feed helium with an auto air conditioning compressor. Even if you try to recover the helium, I see you do know it is going to bleed out the cylinder walls, and an ongoing supply is not a reality. You also will not come even close to the internal pressure of the working gas requied. To maintain the kind of pressure, you will certainly need more expensive machinery.

It is a very novel design. Please be carefull and do not lead poison yourself, or burn yourself.

My assesement can be summed up as, to the Stirling trying to get power, the engine is heavy to move and light to hold up.

I can suggest the following. Give up on it, and try this. Find the project from MIT that used old automobile parts, just like you are using, that built an organic Rankine cycle engine successfully. I bet you could improve on it, going in the direction you are.


At least you are using the old noodle!


If I lived in Oz and had all that sunshine and junk parts, I think I would pick a much simpler solar powered steam engine.

My last tip and post for you.
Study using a liqiud for a working fluid. It doesn't expand as much, but provides far more power for less movement. It also moves slower, and would be less dangerous. Your design for internal heating and cooling will work much better too!




- Joe

[haselhurst]

HI Joe,
Reply to your comments below.
Geoff

If you have anywhere close to a working engine with even close the power you say, it would be a miracle. I went over your new design, I sorta followed your equations, and I think the machine probably is not going to even turn over!

GH - Well it is good to do the physics first - see if it works in theory. But yes, I don't expect it to work. However I know I will learn a lot in failing - and have a lot of fun in the process.

It is heavy and requires lots of external system support. It will also be difficult to sell this thing, since it contains so much lead, which you will keep molten.

GH - By a lot of external support you mean that the engine needs to pump itself up to and maintain its working pressure - not that hard really. Lead is good because it has high heat transfer and it does not explode with air. SO a lead (hot side) water (cold side) is useful as you can just use air to keep it pressurised. But I am just experimenting. There is also Hitec salt that can be used on the hot side.

I also see you are asking for free information for a machine you are trying to patent.

GH - I believe in free access to free knowledge. I patent things just so i have some control over their use. I have no interest in money really (I have enough to live simply). My motivation is 3 fold, curiosity / challenge, I don't have mains power so it is useful for me, and I like its humanitarian 3rd world possibilities.
If you want to use any of my ideas then just discuss with me - as long as they are for uses good for humanity then I am happy!

I understand you are in the middle of a project and very excited, so my grand theories get skimmed over. So, let me review what happens with other commercial attempts at a power producing Stirling.

GH - Too true. But this is a post on my design for Stirling engines. If you want my thoughts on your design ideas just post them in a new thread and I will gladly reply (for what it is worth!)

For one, most have to heat the thing so hot, they reach a limit that causes metal fatigue fairly quickly. Your design of internal heating will help, but you still will not have enough heat, even though the theory says you will. Most of the equations out there are static, in the sense they really do not watch the real dynamics of all the forces involved.

GH - Philosophers are a pain in the ass - because they will always ask you for the source of the truth. So where is your source of truth? You may well be correct - but I prefer to experiment to confirm things. And i have a cool little laser pointer temperature meter that measures to 500C so today I am going to experiment with lead and measure the air temperature coming out of the hot side using different dipping materials and also just injecting the air into the molten lead. A bit scary - but a lot of fun.

Also, the second most common method of getting power from a Stirling is to compress the gas. You do this, and continue to feed helium with an auto air conditioning compressor. Even if you try to recover the helium, I see you do know it is going to bleed out the cylinder walls, and an ongoing supply is not a reality. You also will not come even close to the internal pressure of the working gas requied. To maintain the kind of pressure, you will certainly need more expensive machinery.

GH - If I use helium then the motors will be put in the big cylinders (400mm D) to prevent leaks and it will not use an external pump. I plan on only using external pump if I use air.

It is a very novel design. Please be carefull and do not lead poison yourself, or burn yourself.

GH - Yes, this is my worry. I try to think first and be careful, but we humans are blind to obvious things, so there is always risk.

My assesement can be summed up as, to the Stirling trying to get power, the engine is heavy to move and light to hold up.

I can suggest the following. Give up on it, and try this. Find the project from MIT that used old automobile parts, just like you are using, that built an organic Rankine cycle engine successfully. I bet you could improve on it, going in the direction you are.

GH - I will search this later. Thanks. And I cannot give up on something that I am having such fun thinking about. I love experimenting / creating. I am surprised you wrote that.

At least you are using the old noodle!

GH - I try. I accept I am stupid - to me this is simply an aspect of our animal evolution.

If I lived in Oz and had all that sunshine and junk parts, I think I would pick a much simpler solar powered steam engine.

GH - Well solar voltaic panels are the obvious future and are coming along in leaps and bounds (search thin film plastic solar panels). But they are still 5 years away from being cheap.

My last tip and post for you. Study using a liqiud for a working fluid. It doesn't expand as much, but provides far more power for less movement. It also moves slower, and would be less dangerous. Your design for internal heating and cooling will work much better too! - Joe

GH - Yes the forces would be enormous but over very short distances. Worth thinking about though.

Thanks Joe. Don't be put off my my blinkered enthusiasm for my own ideas! I am here to help and share knowledge, to experiment and learn. I appreciate you being part of that. Very much!
Cosmic cheers,
Geoff

[bptdude___2569]

No worries, mate.



Good luck.

[moreshkokane]

Geoff

I find your design fascinating and am very interested in knowing how your testing is coming along. I checked some of the figures you are expecting and if you get even close to the output and efficiency you say you will it will be a game changer.

My colleagues and I are involved in a startup http://www.newpowerindia.com and are exploring the viabilty of a CSP project in India based upon Stirling engines. We have a patented design that allows us to build very large lens based collectors.

We are trying to find a cost effective engine that can be coupled with the system and have done some amateur attempts to build one ourselves.

http://www.youtube.com/watch?v=d3lsUxwCszQ

Right now we are exploring a free piston design. Please let me know how your testing is coming along.

Cheers !
Moresh