Solar powered stirling engine project

[Morris Dovey]

At least I /think/ it's a stirling engine. It has only air and water
as moving parts; and I'm looking for a clear explanation of how and
why it works.

It's been a very long time since I did anything with Boyle's Law; and
forty years later I'm struggling to produce a set of parametric
equations that'll let me design in the behavior I want from this
thing.

I've put drawings and a prose description on the web page at the link
below - and there's enough info for you to build your own (for
probably less than $5)

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html

[ecarecar]

Flash!!

You may have invented the Free-Piston Stirling Engine.

To be sure, check out William Beale and the Free-Piston Stirling Engine.

Post by Morris Dovey
At least I /think/ it's a stirling engine. It has only air and water
as moving parts; and I'm looking for a clear explanation of how and
why it works.
It's been a very long time since I did anything with Boyle's Law; and
forty years later I'm struggling to produce a set of parametric
equations that'll let me design in the behavior I want from this
thing.
I've put drawings and a prose description on the web page at the link
below - and there's enough info for you to build your own (for
probably less than $5)
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto/StirlingProject.html

[Morris Dovey]

Thanks! I'm probably neither the first nor the last. I'll consider it
as a possible indication that I may be on the right track. :-)

My Google search didn't turn up anything that I could recognize as
being computationally useful. Are you aware of any good/specific
resources?


ecarecar (in ***@centurytel.net) said:

| Flash!!
|
| You may have invented the Free-Piston Stirling Engine.
|
| To be sure, check out William Beale and the Free-Piston Stirling
| Engine.
|
|
|
| Morris Dovey wrote:
|
|| At least I /think/ it's a stirling engine. It has only air and
|| water as moving parts; and I'm looking for a clear explanation of
|| how and why it works.
||
|| It's been a very long time since I did anything with Boyle's Law;
|| and forty years later I'm struggling to produce a set of parametric
|| equations that'll let me design in the behavior I want from this
|| thing.
||
|| I've put drawings and a prose description on the web page at the
|| link below - and there's enough info for you to build your own (for
|| probably less than $5)
||
|| --
|| Morris Dovey
|| DeSoto Solar
|| DeSoto, Iowa USA
|| http://www.iedu.com/DeSoto/StirlingProject.html

[ecarecar]

I am not an expert on Free-Piston Stirling engines.

They are, I think, not easily modeled.

I would refer you to Sunpower, a company founded by the inventor
of the Free-Piston Stirling engine, Dr. William Beale, located in, as I
recall, Athens, Ohio.

http://sunpower.com/

Post by Morris Dovey
Thanks! I'm probably neither the first nor the last. I'll consider it
as a possible indication that I may be on the right track. :-)
My Google search didn't turn up anything that I could recognize as
being computationally useful. Are you aware of any good/specific
resources?
| Flash!!
|
| You may have invented the Free-Piston Stirling Engine.
|
| To be sure, check out William Beale and the Free-Piston Stirling
| Engine.
|
|
|
|
|| At least I /think/ it's a stirling engine. It has only air and
|| water as moving parts; and I'm looking for a clear explanation of
|| how and why it works.
||
|| It's been a very long time since I did anything with Boyle's Law;
|| and forty years later I'm struggling to produce a set of parametric
|| equations that'll let me design in the behavior I want from this
|| thing.
||
|| I've put drawings and a prose description on the web page at the
|| link below - and there's enough info for you to build your own (for
|| probably less than $5)
||
|| --
|| Morris Dovey
|| DeSoto Solar
|| DeSoto, Iowa USA
|| http://www.iedu.com/DeSoto/StirlingProject.html

[Morris Dovey]

ecarecar (in ***@centurytel.net) said:

| I am not an expert on Free-Piston Stirling engines.
|
| They are, I think, not easily modeled.
|
| I would refer you to Sunpower, a company founded by the inventor
| of the Free-Piston Stirling engine, Dr. William Beale, located in,
| as I recall, Athens, Ohio.
|
| http://sunpower.com/

Me too (In fact, I'm not an expert on _any_ type of engine).

It appears to be a collection of problems. Heat transfer into the
engine, heat transfer to air and water, rate of vaporization of some
amount of water and the associated volume change, expansion of air,
etc., etc. (ad nauseum)...

I'm pushing the modeling to the back burner for the time being. Pretty
much by accident, I have something that works - so I'm going to see if
the apparatus can be scaled up from a toy made of 1/2" tubing to a 12'
tall monster made of 4" schedule 40 PVC pipe - and heat it with a
parabolic trough solar concentrator. The only challenge will be to get
the (500-800F) heat from the concentrator to the inside of the tube
without melting the PVC.

If I can get that to oscillate, I'll build the pair of check valves
and find out how well it'll work as a pump.

I visited the sunpower.com site - but didn't find anything useful to
me. They seem to like high-tech and expensive; and I prefer low-tech
and cheap for this application. My intended end-user can't /afford/ a
high-tech precision solution.

--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

[ecarecar]

It did occur to me that what you have is not a Stirling engine. I have
yet to see
any Stirling engine -- free-piston or constrained -- that did not have
a regenerator.
From your drawing, I did not see anything that could reasonably or
effectively
operate as a regenerator.

You might want to look more carefully at the Sunpower site. From what
little I know of
Dr. Beale's efforts, high tech, at least in the physical manifestation
of his designs,
is exactly the opposite of
much of his efforts. I believe a lot of what he was doing was aimed at
impoverished
African regions. However, the last time I was familiar with his work
was over 20 years ago.

Post by Morris Dovey
| I am not an expert on Free-Piston Stirling engines.
|
| They are, I think, not easily modeled.
|
| I would refer you to Sunpower, a company founded by the inventor
| of the Free-Piston Stirling engine, Dr. William Beale, located in,
| as I recall, Athens, Ohio.
|
| http://sunpower.com/
Me too (In fact, I'm not an expert on _any_ type of engine).
It appears to be a collection of problems. Heat transfer into the
engine, heat transfer to air and water, rate of vaporization of some
amount of water and the associated volume change, expansion of air,
etc., etc. (ad nauseum)...
I'm pushing the modeling to the back burner for the time being. Pretty
much by accident, I have something that works - so I'm going to see if
the apparatus can be scaled up from a toy made of 1/2" tubing to a 12'
tall monster made of 4" schedule 40 PVC pipe - and heat it with a
parabolic trough solar concentrator. The only challenge will be to get
the (500-800F) heat from the concentrator to the inside of the tube
without melting the PVC.
If I can get that to oscillate, I'll build the pair of check valves
and find out how well it'll work as a pump.
I visited the sunpower.com site - but didn't find anything useful to
me. They seem to like high-tech and expensive; and I prefer low-tech
and cheap for this application. My intended end-user can't /afford/ a
high-tech precision solution.
--
Morris Dovey
DeSoto Solar
DeSoto, Iowa USA
http://www.iedu.com/DeSoto

[LinuxGuru]

Post by ecarecar
It did occur to me that what you have is not a Stirling engine. I have
yet to see
any Stirling engine -- free-piston or constrained -- that did not have
a regenerator.

A re-generator is not a required part of a sterling engine. In practice
it helps efficiency in theory it hurts efficiency as it adds "dead air"
space, resistance, etc...