a Silly idea

[Gab250]

Hey, I know for a FACT that this idea will NOT work, but I fail to understand exactly WHY, so I will run it past you guys (and gals) If you get a very high amperage car (or Truck) alternator, and both wire it to an electric motor that requires less current to run than the alternator will put out, and use the electric motor to DRIVE the alternator, and you use a Battery to start the electric motor, WHY wont the electric motor keep on running? I know it wont work but WHY? lol

Gab

[crazy]

Perpetual motion is what you are trying to acheive.
. have a read here about energy conversion. It should help explain that each time you convert energy , you lose some.

[Fernbay]

Of course it would work - IF you could make a motor or generator/alternator with better than 100% efficency

I bet you can't

Friction is your enemy

[trash]

Ah, we've all tried this experiment.
I think I first thought of it when I was about 7 years old and I built it.
Never one to be told that ya just can't do it.
Not knowing a lot about what I was doing, I tried a 12V motor and a 3V motor. After a few minutes I realised I had AC/DC issues and built a bridge rectifier.
Still not luck ... I tried different motors and always ended in failure.

The issue isn't voltage or current, it's power.
Hand cranking motors I realised that high power motors where harder to crank than lower power motors, especially when short circuit.

I encourage anybody to actually dismiss what they are told about the laws of thermodynamics and actually build and test it for themselves. This is science in action and it's often the best way to learn.

In this case as fernbay as mentioned, nothing is 100% efficient.
So each time you convert from electrical to kinetic energy you loose energy.
You also loose it in friction of the motors and the resistance of wires.

Take it to the next level. I was lucky, because ceramic high temperature superconductors were invented when I was still in high school and I not only had access to them, I was taught how to make them.
This meant in theory I could replace the resistive wires with superconductors, the windings could be made from superconductors, and the bearings on the shaft could be magnetic and superconductive to float the assembly.

There are some interesting effects when working with superconductors like inverting waveforms etc. But even after all this effort, air resistance still catches up to you and the experiment (very slowly) grinds to a halt.

When you consider how much energy you put into pumping the heat out, or putting the experiment into a vacuum chamber, and still the experiment won't even achieve unity. (no loss).

[Uncle Fester]

Something that always ghosted around in my head since a kid was a motor that powers a fridge compressor "produced" more energy (in form of heat) than it "consumes".
Therefore this heat, if sufficiently converted back to electricity could power the motor for the fridge compressor and still have enough energy left to power something else as well.

Later (seventh or eighth year high school) I heard something about the second law of thermodynamics, that postulates that such a machine can not be constructed.
I remember arguing with the teacher and not being satisfied with the outcome and explanations.
This is not perpetual motion as the energy is taken from the surroundings with the side effect of cooling the atmosphere(in that observed system), which some ppl might find beneficial .

Such heat to electrical converters could be improved Stirling motors or probably better, inert systems like reversing a Peltier element but using more efficient materials.
A useful semi-conductor combination could possibly be found with enough research.
I played around with Peltiers and got probably way less than 10%, just enough to get a fan running.
The efficiency of the conversion could be lower than 70% as a thermal pump can operate with 300% efficiency, i.e 1kW electrical needed to pump 3kW thermal... well to operate only as a fridge roughly 35%.

[trash]

Ah, well such machines do not violate thermodynamics.

Lets look at it this way....

You're fridge is a machine that moves heat from one place to another.

If you have two boxes, both at the same temperature, lets use TTU's (trash thermal units) each box contains 10 TTU's.
Now there must ALWAYS be 20 TTU's total... since you cannot create or destroy energy (we'll ignore matter for the time being).

You're heat pump takes 5TTU's from one side an puts them on the other.
Now one has 5TTU and the other 15TTU. Pretty simple. One box is hot, the other is cold.

Now, your heat pump is not a perfect machine, it too produces heat as a byproduct of doing its work. Lets say it uses 4TTU's of energy and dumps 2TTU's into the system as part of it's operation 50% efficient. Now one box has 5TTU and the other 17TTU ... that appears that we got an increase of 7 TTU's for nothing more than 4TTU's input.

This is how the new heat pump hot water systems work. They appear to be very efficient, but they are actually stealing heat or mopping up heat from somewhere else.

[Uncle Fester]

So would you agree with me that a fridge could be constructed to run indefinitely on it's own until equilibrium in the universe is achieved ?

I am wondering if a Stirling motor could be internally included in a thermal pump to improve efficiency and direct drive the compressor.
The compressed and hot refridgerant could directly enter the Stirling motor's cycle.
ATM Stirlings can reach up to 30% efficiency which is just not enough (although very efficient for piston engines) and also need high temperatures to get near that value, so a bit of a challenge to construct a heat pump that can operate @ several hundred °C.
Interesting is that a Stirling motor is a heat pump in reverse.

... or I design a heat pump that needs only 20% mechanical energy to convert 100% thermal and then we're there.

[bambbbam]

Well a gravity train would run infinitely..

[trash]

Nice try nomeat.... at first it sounds like a clever idea, but it's still very much the same thing as the motor/generator setup.

Stirling engines work on a thermal gradient. Bambbbam's quote of a train that rolls down a never ending hill is the same thing. But rather than gravity, heat is the energy, and height is measured in Kelvin (or degrees if you like).

We have Box A and Box B again .... the refrigeration system pumps heat from one box to the other, and adds a little.

The stirling engine uses the gradient to power it, It allows heat to move from box B to Box A and produces motion in doing so.
At the same time it too adds heat from friction etc... but not to box B, it adds it to Box A by default. There is no escaping it as this is where the waste energy ends up.
The end result is that while you picked up a gain in energy from friction into the storage of the system, you lost it again in the conversion of the stirling engine.

You don't get Nuffin for Nuffin in physics

The concept I have considered for "other" more fringe uses, on this side of unity.

Coal fired power stations are an interesting example.
Lets start with the absolute basic coal power station.
We burn coal, it heats water to steam, that steam turns a turbine and we get electricity ... nothing more complex than that.

In reality we conserve resources and recycle material.
The steam is condensed back to water and then sent back to the boiler.
It might seem like this secondary cooling is wasted energy, but it's not.
The steam condensed behind the turbine creates a vacuum making the turbine system run more efficiently.

Another method used is the exhaust gases are used to heat a metal plate. Air drawn into the burner is pre-heated as it is drawn over the plate, so heat energy is not lost out the chimney. The trick is to run this system so that there is still enough energy to keep the burners running without the exhaust gas cooling too much and impeding the exhaust system.

A newer development is to use a direct turbine. Coal dust is burned in the turbine and the exhaust gases used to boil water and the remaining exhaust gas is used to pre-heat the air intake.

The idea I've been running past a few friend is to use a heat pump system to recover the latent heat of the secondary cooling system. Recovering 10 degrees C from 100 litres and using it to boil 10 litres of water via a heat pump. effectively mopping up all the latent heat. The energy mopped up is then used to drive the latent heat system and any surplus heat is sent back to the boiler.
I've been told that they don't use this exact method, but there are some places that do something similar, though I'm not familiar with the details of how they do it or how much energy they recover.
It's not a free energy system, it's just like collecting lots of crumbs to make another new cake. It requires energy which it gets from waste heat. The more waste heat there is, the better it works, but this means the less efficient the host power station is.

[trash]

I have heard about a car powered by a latent heat recovery system too.
I've tried searching for it to see how it works or at least if it is some sort of fraud. There isn't a claim of a car that runs on air, but from what I can gather it uses an ammonia/hydrogen/water heat exchanger system and uses kero or LPG as the fuel.

[muddy0409]

The simple fact is: You CANNOT produce energy from nothing!
ALL energy is produced from some other type of energy!

The End!!

All energy that will ever be produced in the universe has already been made, it's just gotta be made useful by conversion.

[mudcrab]

The Laws of Energy Thermodynamics springs to mind guys

[trash]

The End!!

It's never the end. Just to say such a thing is bad science.
Notice to all students of science. QUESTION EVERYTHING.
Science relies on peer review and always questioning if theory is correct even and especially if it already appears so.

Even if you can't knock some rock solid evidence over, you will better understand why. Or discover some other related ideas.

If kids stop trying to connect motors and generators together in various combinations then it shows they have become more stupid than the generation of kids who tried and failed.

The simple fact is: You CANNOT produce energy from nothing!

Yet that appears to have happened about 14.5 billion years ago.

ALL energy is produced from some other type of energy!

Did you forget mass ? Energy and Mass are interchangable.

All energy that will ever be produced in the universe has already been made, it's just gotta be made useful by conversion.

This also does not appear to be true.
The expansion of the universe is accellerating, and that energy does not appear to be sourced from the universe internal.
The door is still wide open for a valid theory considering the entropy of the universe as a whole.

[Chimp]

think i first thought about this when iwas 7 or 8 to. took me a long time to understand but it all comes down to friction and heat generated etc, makes you looose energy.

youd be wirth a fortune if you could create perpetual motion

[bambbbam]

The Laws of Energy Thermodynamics springs to mind guys

In this house, we obey the third law of thermodynamics!

[trash]

In order to achieve greatness, you must be prepared to fail greatly.

Failure, it paves the road to success !

Bloody navman.... where the hell is this road to success ? I'm lost !

[Uncle Fester]

Nice try nomeat.... at first it sounds like a clever idea, but it's still very much the same thing as the motor/generator setup.

Stirling engines work on a thermal gradient...

Yarrh... it sort of sunk in when I realised that the Stirling motor is a reverse heat pump.
So it's just a heat pump powering another heat pump.

Nevertheless I am still stealing energy from the environment so this is NOT nuthin for nuthin.

A means of thermal to mechanical or electrical energy conversion with sufficient efficiency should be technically possible.

Like the infamous hunt for the recipe of a practical room temperature super conductor, we could look for something better than twisting a constantan and copper wire together to directly convert heat into electricity, although it looks like someone is on it:

but only 7.8%, a long way to go.
Still, I was astonished how much power a Peltier element generates at only a delta T of 30°.

I must concentrate more on failing... but so little time