Thread: Possible Fantastic Idea. Need Scientific Minds to Review

All,

Science folks. I just had a great idea utilizing the "artificial muscle" that has been in the new lately while driving down the road today. &I have created a spot to explain it here:
thermalpiston.blogspot
This is not a personal blog or anything - look and you will see - I just needed a way to post something to the internet in a quick and easy manor. There is only the one "post" and it explains the idea. Please let me know your thoughts. If anyone knows a better place to put this let me know. I have had trouble submitting this post likely because of the link above I am trying to put in. If you are an Admin please help.

Trey Long

You can't link to other sites in your first post because that is spamming. Why don't you post your idea here rather than ask us to go to another site?

Thermal Piston Idea

Pass this link along to anyone who has a scientific inclination, tweet, like, +1, etc. on the small chance that I have stumbled onto something fantastic.

Introduction:

As I was driving down the highway to pickup some furniture that my wife plans on re-finishing I was listening to a podcast. This particular podcast is called Science Friday and I noticed a segment on artificial muscles which correlated to some recent news that I had read on the subject. As I listened I was hit with a fantastic idea. The idea hinges on a particular attribute of the artificial muscle. The muscle itself is created simply with a bit of coiled glorified fishing line, the muscle "relaxes" when cooled and "contracts" when heated. Most material expands when heated - this is different which makes it interesting. The material likely expands but the muscle itself contracts up to 50%.

Idea:

This idea is being posted freely for all to see. If this "thermal piston" actually functions how I imagine then in theory the implications could be world changing. My hope is that it is, although ideas such as these are typically flawed or unfeasible.

Description:

Diagrammatic Sketch:

Prime it:
- Put the piston into a cold environment (colder than typical outdoor temperature). Let the artificial muscle relax fully and piston fill to surrounding pressure.

Set it into steady state motion:
- Put the piston into a room temperature environment and leave it there.

State 1:
- As the previously cooled piston begins to warm the artificial muscle begins to contract.

State 2:
- The muscle fully contracts.
- The piston itself has risen producing mechanical energy.
- The pressure in the piston is increased.

State 3:
- At the peak of the piston's contraction a pressure relief is enabled.
- The rapid pressure drop creates a colder temperature within the piston
- The cooling subsequently relaxes the muscle which resets the piston, the piston is "refilled" through a check valve.

State 4:
- The process repeats indefinitely assuming that the ambient temperature remains within a certain temperature band.

Discussion:
This is not a perpetual motion machine, heat is absorbed from the surroundings and converted into mechanical energy. Applications would include low cost energy available anywhere. Waste "cooling" which could possible be utilized for comfort cooling. In general the heat into the system would need to be controlled. Lastly, perhaps increased efficiency or calibration could be accomplished by use of refrigerants for phase change, low/high temperature ranges could be tested, and artificial muscle construction could be modified to tweak properties.
For those that enjoy tearing down ideas I challenge you to offer solutions as well as criticism. This idea has gone from my brain onto the internet in a matter of hours - I could easily be missing something, please offer comments below.

-Trey Long

Originally Posted by TreyLong

Prime it:
- Put the piston into a cold environment (colder than typical outdoor temperature). Let the artificial muscle relax fully and piston fill to surrounding pressure.

Can you give an example of how you would do this?
For example: imagine I have a water pump in my house. How would I cool it to "colder than typical outdoor temperature"?

No.
It will reach equilibrium: expansion of the muscle will, at some point, be matched by the increased pressure in the cylinder.
Then it will simply stop doing anything.
Even if it's cooled down from that point it will reset and only expand to (at a guess ¹) lower pressure than previously - diminishing returns. Especially given friction losses (and that's before you start drawing off pressure to do any useful work).

There's also the question of what pressure you're expecting: i.e. a useful pressure may require an unfeasibly large muscle - that's dropping you straight into massive losses from the get-go.
Without a bunch of hard numbers I can't see it as being anything more than a (temporarily ²) amusing desk top toy.

All of the above is first-blush assessment: lacking, as I said, hard numbers (on the power the muscle produces and what it's expected to actually do) I can't do much more. But, then again, it's also an assessment I'd have turned in if the idea had been presented at any engineering meeting I was present at.

1 I can't be bothered to work it out. But, since there will be less pressure than intended the cooling will be less than optimum and hence the "low temp contraction base" will be higher than previously: providing less overall expansion.
2 I.e. running for 5 or 10 minutes at a time before needing to be stuck back in the fridge.

Originally Posted by RedPanda

Originally Posted by TreyLong

Prime it:
- Put the piston into a cold environment (colder than typical outdoor temperature). Let the artificial muscle relax fully and piston fill to surrounding pressure.

Can you give an example of how you would do this?
For example: imagine I have a water pump in my house. How would I cool it to "colder than typical outdoor temperature"?

Simple, but it would, magically, require you to eventually input the same amount of energy (in a perfect system, more in a real one) that you get from the machine.

This sounds like another attempt at perpetual energy.

Originally Posted by TreyLong

Thermal Piston Idea

Pass this link along to anyone who has a scientific inclination, tweet, like, +1, etc. on the small chance that I have stumbled onto something fantastic.

Introduction:

As I was driving down the highway to pickup some furniture that my wife plans on re-finishing I was listening to a podcast. This particular podcast is called Science Friday and I noticed a segment on artificial muscles which correlated to some recent news that I had read on the subject. As I listened I was hit with a fantastic idea. The idea hinges on a particular attribute of the artificial muscle. The muscle itself is created simply with a bit of coiled glorified fishing line, the muscle "relaxes" when cooled and "contracts" when heated. Most material expands when heated - this is different which makes it interesting. The material likely expands but the muscle itself contracts up to 50%.

Idea:

This idea is being posted freely for all to see. If this "thermal piston" actually functions how I imagine then in theory the implications could be world changing. My hope is that it is, although ideas such as these are typically flawed or unfeasible.

Description:

Diagrammatic Sketch:

Prime it:
- Put the piston into a cold environment (colder than typical outdoor temperature). Let the artificial muscle relax fully and piston fill to surrounding pressure.

Set it into steady state motion:
- Put the piston into a room temperature environment and leave it there.

State 1:
- As the previously cooled piston begins to warm the artificial muscle begins to contract.

State 2:
- The muscle fully contracts.
- The piston itself has risen producing mechanical energy.
- The pressure in the piston is increased.

and the temp of the pressurized air increases.

State 3:
- At the peak of the piston's contraction a pressure relief is enabled.
- The rapid pressure drop creates a colder temperature within the piston

the drop in temp will be as much as was gained when the gas was pressurized.

- The cooling subsequently relaxes the muscle which resets the piston, the piston is "refilled" through a check valve.

State 4:
- The process repeats indefinitely assuming that the ambient temperature remains within a certain temperature band.

No, the process will not repeat indefinitely, only until the system equalizes to room temperature. Any heat engine requires a heat source and a heat sink and to maintain operation, the heat sink must remain cooler than the heat source. Your system will die down once the initially cooled down object absorbs enough heat from its surroundings. The only way to keep it running would be to keep cooling it back down between each cycle.

All,

Thanks for the responses. Of course - you are probably right, I realized how it sounds. However, allow me to play the optimist:

RedPanda: How it is initially cooled was not really the problem, however it is a good thought, I will elaborate below.

Dywyddyr: Your post is likely the case. I have not researched the muscles that has been in the news lately and I am not sure if there is really that much info out there at this point anyways. What delta T is required? how much pressure can it generate? etc. As you mentioned, there would very probably be a diminishing return, I just don't know, its not like there is a table or something that describes what the muscle does in different conditions but I would be interested to know.

Flick Montana: It does sound like perpetual energy - at first glance. The idea was, theoretically it absorbs heat from the surroundings each cycle since perpetual energy is impossible.

Janus: I am not sure I agree with you completely - I would think - theoretically it should cycle, at least once... depending on the properties of the muscle. As you mentioned above, the temperature increases, but it could easily be rejected to the environment before the drop in pressure.


My further thoughts would be:
1. Back to RedPanda's original question and a comment Dywyddyr made, if the cooling "Primer" does need to be reset then I would wonder how often. 2 seconds, 2 minutes? 2 hours? etc. because as luck would have it most locations of the world have a dependable daily delta T once every day (day versus night).
2. Is there more energy in than out, is it useful? Upon further thought I am not sure how useful it could possibly be. Even if all of my optimistic assumptions come true it would theoretically have to pull the energy out of the environment via conduction. This means that the max possible energy generation would be the (surface area of the piston)*(thermal conductivity of the piston)*(the delta T). It would have to be scaled up pretty big to be useful I would think.
3. Perhaps the more useful purpose would be as a source of cooling. I have not really thought about how that would work or what the optimal use of the muscle to that end would be. Energy would have to be added to avoid Dywyddr's diminishing returns but I wonder if efficiencies would be better then current screw, reciprocating, scroll, or centrifugal compressors.
4. Lastly, I will leave you with one more thought. This artificial muscle apparently "contracts" with heat and "relaxes" when cooled, other materials do the exact opposite, I wonder if there would be a way to take advantage of two materials having the opposite reaction to change in temperature... as mentioned before, we get a reliable delta T each night.

I wonder if the ideas involved in how Stirling engines work might help you.

Originally Posted by TreyLong

RedPanda: How it is initially cooled was not really the problem, however it is a good thought, I will elaborate below

If you ignore the energy needed to reset the piston then how are you ever going to know how efficient the piston is?

A partially submerged structure might have a continuous temperature difference which might be used for the creation of energy.

I don't think Trey is trying to create energy, or invent an efficient machine. For an artificial muscle, what you need is something that can store and use a lot of energy in a small volume. I don't think the contracting rubber band with thermal energy storage would fit the bill, as Dywyddr pointed out. You just can't get very much power by transferring heat from a room into something cold.

I have no idea how strong the fishing line muscles could be or how" world changing " the idea would be. Probably not very much in either case.
However steam engines were pretty much thought of as toys or university demonstrations until James Watt applied himself to making the Newcomen engine more efficient.

So far Trey has no real way of controlling the heating and cooling cycles.

Maybe making a power engine out of this stuff is not the way to go. Maybe the way, if the material is cheap, is to use it in a thermally active linkage. Maybe to control ventilation flaps or something like that.

Originally Posted by TreyLong

This is not a perpetual motion machine, heat is absorbed from the surroundings and converted into mechanical energy.

That is the definition of a perpetual motion machine of the second kind, one that converts ambient thermal energy into useful work. It violates the Second Law of Thermodynamics. You generally need a temperature _differential_ to generate useful energy. If you try to use the machine to create the temperature differential, that will always require more energy than you can get out of it.