Re-invent the steam engine.?

[flantoons]

Hello,

 

I am trying to re-invent the steam engine.

Is there a way to use volatile chemicals to create gas expansion, that is cheaper than boiling water to produce steam?

 

Thanks for your time and consideration.

[insane_alien]

well, you could replace the water with a more volatile chemical but thats going to create other problem as well, especially if you get a leak(which is likely).

 

the only problem with this is thatyour fire will still need to be much much hotter than your working fluid in order to achieve the same vapour production, so in reality the heating cost won't be that much different asthe tempeature difference of the fires willbe negligble if not non-existant.

 

and then you have a condensation problem, as you have a lower temperature difference between external conditions and what you are condensing, you'll need a larger area to keep a good heat transfer rate.

 

using another fluid would likely throw up a host of other problems. watter is conveinient.

 

you might want to look more into the heating method and try and get a more efficient way of creating the steam, or perhaps a method that can change loads quickly(with ordinary steam engines you had to plan a fair bit ahead so you were creating the right amount of steam later on. if you kept shovelling full pelt and stopped at a station then you'd either need to vent steam profusely or there'd be a boiler explosion.

[flantoons]

Thanks insane-alien.

I was thinking maybe a mini explosion would create gas under pressure, to drive the engine...but how can I make these mini explosions very cheaply?

[insane_alien]

Thanks insane-alien.

I was thinking maybe a mini explosion would create gas under pressure, to drive the engine...but how can I make these mini explosions very cheaply?

 

what you're describing there is an internal combustion engine(like you'd find in your car), nothing like the steam engines which were external combustion.

[flantoons]

Thanks, yes I understand what you say...but I am looking for an EXternal combustion or explosion to create gas pressure to then feed a "steam" engine.

[Cap'n Refsmmat]

How are you going to create gas pressure with external combustion? I'm not quite sure what you're trying to do.

[insane_alien]

he wants to pwer a steam engine with explosions. doing this externally is going to be incredibly inefficient to the point of uselessness.

[Skye]

Thanks, yes I understand what you say...but I am looking for an EXternal combustion or explosion to create gas pressure to then feed a "steam" engine.

 

And you'd need a mechanical couple to do that, say a cylinder-piston device...

[npts2020]

Hello,

 

I am trying to re-invent the steam engine.

Is there a way to use volatile chemicals to create gas expansion, that is cheaper than boiling water to produce steam?

 

Thanks for your time and consideration.

 

Few things are cheaper than boiling water. Not only that but water is particularly well suited for this use and a fairly safe substance to work with. Any possible alternative I can think of will be toxic, volatile, less efficient, and/or more expensive.

[insane_alien]

... volatile,...

 

ummm, thats the point to an extent.

[lazygamer]

too late, kender engine is allready invented.

You use a gas, that is at for example -200 C at 15psi pressure, then you put it in a radiator, the air around the radiator warms up the gas inside, and voilà, you have 150-200psi at room-temperature, which you send through a turbine or whathaveyou and a pressure-decrease valve, then you just repeat.

[Mr Skeptic]

too late, kender engine is allready invented.

You use a gas, that is at for example -200 C at 15psi pressure, then you put it in a radiator, the air around the radiator warms up the gas inside, and voilà, you have 150-200psi at room-temperature, which you send through a turbine or whathaveyou and a pressure-decrease valve, then you just repeat.

 

Except it's not an engine. What it boils down to is a gas inside a tube heated by the sun.

[lazygamer]

its something that creates mechanical motion, that's an engine in my world, and probably allmost everyone else's world aswell.

[npts2020]

too late, kender engine is allready invented.

You use a gas, that is at for example -200 C at 15psi pressure, then you put it in a radiator, the air around the radiator warms up the gas inside, and voilà, you have 150-200psi at room-temperature, which you send through a turbine or whathaveyou and a pressure-decrease valve, then you just repeat.

 

Except that once you send it through a "pressure-decrease" valve, it takes energy to repressurize, in fact, more energy than you got out of the fluid to begin with.

[Mr Skeptic]

its something that creates mechanical motion, that's an engine in my world, and probably allmost everyone else's world aswell.

 

Hey I can say that I can flap my arms and fly but just because I say so doesn't mean it really is so. The Kender engine doesn't fit the description of an engine and no it won't produce mechanical motion because the laws of physics don't allow it to. No matter how much they say it will.

[lazygamer]

"Except that once you send it through a "pressure-decrease" valve, it takes energy to repressurize, in fact, more energy than you got out of the fluid to begin with."

 

nope, because you repressurize to 15psi, but you have 150-200 psi pushing the turbine...

 

"Hey I can say that I can flap my arms and fly but just because I say so doesn't mean it really is so. The Kender engine doesn't fit the description of an engine and no it won't produce mechanical motion because the laws of physics don't allow it to. No matter how much they say it will."

 

ehem, come with a hypothesis to why it won't work. a very spesific one, cus you can't just go "the laws of physics dont agree" if you don't say entire spesific why it is so. cus I can't be bothered with spending MY time disproving your stab at making it impossible, because you'll have time to figure out 5 new stabs in the same time period. and you can allways come with vague stabs, but try making a well aimed well sharpened stab instead. cus I know you can't.

 

because I know it works, 200 psi pushing a turbine, then a compressor that compresses to 15-20psi, even with 80% loss because of the mechanical loss you'd still create twice the energy it takes to pump it back into the radiator at 20 psi. (20 pounds per square inch VS 200 pounds per square inch, there is a significant difference in force dont you think?)

[Mr Skeptic]

Simple, it purports to be a heat engine but isn't. It isn't a heat engine because it has no heat sink. If you want more details, look here: http://www.scienceforums.net/forum/showthread.php?t=43818#post530128

 

Learn about heat engines:

http://en.wikipedia.org/wiki/Heat_engine

[lazygamer]

the lower pressure after the turbine, right before the compressor, is the heat-sink. lower the pressure and the temperature drops.

[Mr Skeptic]

So the temperature of the gas at that point is higher than the temperature of the surrounding air?

[insane_alien]

that cannot be used as a heat sink for a heat engine. nor even a heat pump. the ambiet conditions are the only place available to dump heat regardless of how col an internal part of the system can get.

[swaha]

how about soda water?

[insane_alien]

that would be absolutely terrible you'd be stuck with a noncondensible component building up in your live steam pipes which would crap up your cylinders/turbine/whatever.

[King, North TX]

What if the system was unpressurised...an 'open drip pan', with a heat activated syphon hose that connects the boil chamber to the resevior. Granted you'd loose LOTS of water, but you could chill a tent to catch most of it...

 

Would that work?

[insane_alien]

so... you want to drive a cylinder/turbine without a pressure differential? yeah... good luck with that.

[PaulS1950]

You know there is a guy in Alaska that is using a low temperature differential turbine to generate power. The pressure is generated by using a refridgerant pumped into the ground as a liquid where it is vaporized (somewhere below the perma-frost but still at very low temps) and returned to the turbine where it spins the blades then into a condenser and back to the pump.

 

This would be harder to do with a moving vehicle but the Japanese had a "working" car using a Sterling engine. It wasn't fast or efficient but it would move under its own power.

If you want to re-invent the steam engine why not make use of an environmentally friendly refridgerant in a closed loop system?