Better engine

[rammstein]

Last year I build a walking beam stirling engine and it was running fine. After a long time tweaking and modifications
I found out that the walking beam is not the best configuration for making a little power ( I only made the beam to understand the principle of the stirling engine). I did found out that the cooling fase made the most power to the flywheel on my engine.
So I was looking for the engine configuration with the largest cooling area and a small heating point without dead areas
I came across the ST 05 G engine and liked the design, but as so many designs on the internet it may or may not work.
To make this engine it takes a lot of lath and milling work.
My question is did someone made this engine or saw it live working?

[dalekh]

Rammstein,

I am curious about your experience of the cooling phase providing more power than the heating phase. I don't know, but I wouldn't assume that this was the result of more power being produced in that phase. It may have something to do with other aspects of your engine, like the weight of the displacer, etc.

As I think about the Stirling cycle, the air in the displacer cylinder is alternating above and below atmospheric pressure as it is heated and cooled. The pressure differences should be the same in both phases of the cycle, I believe, except that one is positive and the other negative. The temperature difference is what provides the change in pressure, but it is always relative to atmospheric - at least in this type engine.



Just some thoughts from here.

Dale.

[jimlarsen]

The first thing I would check in those circumstances if flywheel balance. An out of balance flywheel can make one part of the cycle appear to be stronger than the other.

Jim Larsen
Stirlingbuilder.com

[rammstein]

I know in theory the heating and cooling fases should make the same power ,but with my finger light on the flywheel as friction, I could see the difference. Maybe I made it with some odd dimensions. I think on the 3rd page (1 or 2 years back) of this forum I posted a couple of posts about my engine.

Anyway that project is over, any idee of the ST05 design ? They claimed 500 watt !

[rammstein]

I mean the ST05-G engine, Made by a german guy.
It is a gamme type engine, but with a lot of dead volume.

[goat]

I'm not sure that it's true that the heating and cooling phases produce the same power, that's probably worth reading up on.

What I am pretty sure of is this: If the working gas is expanding then power is coming out, but you have to put power in to get the gas to compress. The reason I think this is because the work you get from a gas is equal to the change in volume of the gas multiplied by the pressure that the change in volume occurs at (expressed mathematically as dW = -P dV here: http://en.wikipedia.org/wiki/Work_%28thermodynamics%29).

[jimlarsen]

If cooling gas causes it to have more volume than it had before it was heated, then your speculation would make sense. But if the gas is always cooled to the same temperature it will have the same volume it had the last time it was at that temperature, provided the environment has not changed. If your engine is getting warmer with every stroke and the gas is never returning to the same low temperature, then yes, you are correct. If this happens, the engine eventually overheats and stops.

It is also possible that your mechanism is not as effective in harnessing power on the cooling cycle. There are many variables to watch for, including friction that changes as parts move in different directions.

Jim Larsen
stirlingbuilder.com

[rammstein]

I think you are all right. I made the beancan walking beam in my garage with little tools.
There are to many variables to make any judgement about the performance.
That`s why I`m looking for other engine configurations and I found it.
It`s the double actuating 4 cylinder in a cirkel alfa type, where the hot end goes to the cold end of the next cylinder.
I can`t decide to make a wobble yoke, swashplate or 2 cranks with 4 crossheads. My choise would be the last one.
I need to do a lot more of research, but I did figure out the hot end and cold end tubing thanks to a certain "soft voice gen" company ;)

I like to hear your opinion about this engine.