Tesla's "Ambient Heat Engine" Experiment

[Tom Booth]

Another thing I think happens is on the return stroke the air in the cylinder is compressed, maybe not to the extent that air is compressed in a fire piston, but the principle is the same.

https://youtu.be/-39wmSBO2FM

It seems strange that you have ignored that fact and are now attempting to conjure up a non observed "contraction" to deny it.

The work gained in expansion is lost in isentropic compression.

Cooling it during compression saves energy. ... And it is internal energy that is rejected as heat. ...

I don't think a diesel engine would work too well if it carried out compression by cooling and removing the heat of compression or removing the "internal energy".

At the start of the compression stroke (in a Stirling engine) the working fluid is cooling and contracting and the piston is driven in by atmospheric or buffer pressure.

Towards the end of the stroke heat and pressure build up suddenly as the velocity of the piston slows down and the momentum is converted to heat.

I don't think I've ever said any different.

Your simplistic either/or scenario is unrealistic.

[Fool]

A turbo charged diesel engine uses an intercooler between the compressor and intake to the cylinder.

[Fool]

Towards the end of the Stirling's compression stroke the displacer is moving the gas to the hot side, and the regenerator is heating the gas. Your description is misleading.

[Tom Booth]

A turbo charged diesel engine uses an intercooler between the compressor and intake to the cylinder.

Apples to oranges.

The intercooler is to prevent OVERHEATING because the turbocharger is hot, being powered by exhaust gases. Different purpose, different application. In an IC engine you want dense oxygen rich air at the intake for better combustion.

Compression in the cylinder hasn't begun.

I feel you are "tracking" me, just to argue for arguments sake in an effort to debunk any comment whatsoever that I make, no matter how ridiculous it makes you look. That IS against the forum rules, so please STOP!

[Tom Booth]

Towards the end of the Stirling's compression stroke the displacer is moving the gas to the hot side, and the regenerator is heating the gas. Your description is misleading.

True, (in bold) but so what?

viewtopic.php?t=5556

You want all the heat you can get at TDC.

Cooling at BDC increases velocity at the start of the return stroke which is converted to heat at TDC.

The displacer movement adds additional heat.

You may not be able to comprehend that, but there is nothing "misleading' in my description.

[VincentG]

A turbo charged diesel engine uses an intercooler between the compressor and intake to the cylinder.

Pretty sure Tom was talking heat of compression, the very basis of diesel ignition.

[matt brown]

At the start of the compression stroke (in a Stirling engine) the working fluid is cooling and contracting and the piston is driven in by atmospheric or buffer pressure.

And where is the heat from this "cooling" going ???

Towards the end of the stroke heat and pressure build up suddenly as the velocity of the piston slows down and the momentum is converted to heat.

Did the unicorns explain how momentum is converted into heat ??? In the Carnot camp they say any piston momentum during expansion comes from the kinetic energy of the expanding gas while any 'momentum' during compression comes from a flywheel or other external force. These Carnot lads never said anything about how a decrease in this external force could be converted into heat. Please share...

Your simplistic either/or scenario is unrealistic.

Maybe unrealistic in the unicorn forest, but right on, outside of the forest.

bridge-unicorns.jpg (290.9 KiB) Viewed 3924 times

[Tom Booth]

At the start of the compression stroke (in a Stirling engine) the working fluid is cooling and contracting and the piston is driven in by atmospheric or buffer pressure.

And where is the heat from this "cooling" going ???

The preference would be to have a drop in temperature that results from work output during the power stroke.

Towards the end of the stroke heat and pressure build up suddenly as the velocity of the piston slows down and the momentum is converted to heat.

Did the unicorns explain how momentum is converted into heat ??? In the Carnot camp they say any piston momentum during expansion comes from the kinetic energy of the expanding gas while any 'momentum' during compression comes from a flywheel or other external force. These Carnot lads never said anything about how a decrease in this external force could be converted into heat. Please share...

When the piston slows down, as a result or meeting resistance from the increasing pressure during compression, it looses kinetic energy.

The kinetic energy of an object is directly proportional to the square of its velocity, so as velocity decreases, kinetic energy decreases as well

The "lost" kinetic energy is converted into heat.

This is well established physics. Contrary to your uninformed opinions.

[Fool]

A turbo charged diesel engine uses an intercooler between the compressor and intake to the cylinder.

Pretty sure Tom was talking heat of compression, the very basis of diesel ignition.

Turbocharging and intercooling diesels has improved them to the point where they can be an effective automobile engine. It isn't without it's share of problems and benefits.

If the compression stroke in a diesel cycle were cooled and the fuel ignited some other way at TDC, the cycle would be more efficient. That cycle is called the auto cycle. Since there hasn't been a way to cool the compression cycle effectively, Otto cycles run at a much lower compression ratio. If the Otto cycle were to run at the same compression ratio as the diesel it would be more efficient. The Otto cycle is more efficient than the diesel cycle at the same compression ratio.

Knowing that compression increases gas temperature, crossing that over to a Stirling, the temperature reduction during and at the start of compression can only be attributed to outward heat flow, into regenerator and cold plate.

Cooling during the power stroke is detrimental to energy output.

[Fool]

The "lost" kinetic energy is converted into heat.

What is less misleading?

1: The "lost" kinetic energy is converted into heat.

2: The "lost" kinetic energy is converted into internal energy as seen by a temperature and pressure rise in the gas.

Or are you implying that since there is a temperature rise during compression at a loss of kinetic energy, heat is rejected to the cold plate as a result of the temperature difference, thus reducing the rise? Cause I like that too.

[VincentG]

Professional bloviating. Lots of professional bloviating is what I see on here.

[Tom Booth]

The "lost" kinetic energy is converted into heat.

What is less misleading?

1: The "lost" kinetic energy is converted into heat.

2: The "lost" kinetic energy is converted into internal energy as seen by a temperature and pressure rise in the gas.

Two ways of saying the same thing, IMO.

Or are you implying that since there is a temperature rise during compression at a loss of kinetic energy, heat is rejected to the cold plate as a result of the temperature difference, thus reducing the rise? Cause I like that too.

No.

An IC engine generates heat by combustion.

A Stirling engine has to concentrate heat by other means, certainly not by heat being "rejected to the cold plate". Especially considering at TDC the cold plate is covered and the hot plate exposed.

[Fool]

Heat is not internal energy. To imply that the two are the same, as you often do, is misleading.

To claim gases contract, as you do, is misleading.

A Stirling engine has to concentrate heat by other means, certainly not by heat being "rejected to the cold plate". Especially considering at TDC the cold plate is covered and the hot plate exposed.

Here we are again. Taking about one stroke, completely missing the other stroke, further misleading the discussion towards the power stroke, when it was clearly about the return or compression stroke. Why?

The return stroke begins at BDC. The volume of the gas gets smaller during this stroke. Please consider the whole cycle, or at least the part being discussed.

[Tom Booth]

Heat is not internal energy. To imply that the two are the same, as you often do, is misleading.

To claim gases contract, as you do, is misleading.

A Stirling engine has to concentrate heat by other means, certainly not by heat being "rejected to the cold plate". Especially considering at TDC the cold plate is covered and the hot plate exposed.

Here we are again. Taking about one stroke, completely missing the other stroke, further misleading the discussion towards the power stroke, when it was clearly about the return or compression stroke. Why?

The return stroke begins at BDC. The volume of the gas gets smaller during this stroke. Please consider the whole cycle, or at least the part being discussed.

I'm not "misleading" anything. Apparently you just have poor reading comprehension, always jump to wrong conclusions, entirely misrepresent, misconstrue or intentionally strawman whatever I say, or maybe just don't know a Stirling cycle any better than you know refrigeration.

We were talking about the end of the compression stroke, and what I said applies to the end of the compression stroke, which also happens to be the beginning of the power stroke.

Fancy that.

[Fool]

The end of the compression stroke and beginning of the expansion stroke is where the displacer is moving away from the hot side pushing the gas to the hot side through the regenerator away from the cold side at the highest rate. The piston is at the top of its travel and is moving at its slowest rate. Any temperature changes are a direct result of heat flow from hot plate, cold plate, and regenerator. Little is a result of volume change or work. Another change in direction of this discussion. Another partial cycle description. Why?