Open Systems

[LibreEnergia]

Do you have a mind of your own? Or do you just repeat what others have already said-and whats with all the googlegasms you keep having?.

googlegasms ?  Well I admit to having refreshed my thermodynamics knowledge courtesy of the internet on multiple occasions recently but I can still remember learning this as part of an engineering degree some 30 years ago. We used the knowledge modelling heat engines on software and then actually building,  instrumenting and testing them.

The agreement of the theory to practical experiment was as accurate then as it is today.

[MarkE]

You really need to get out of the past.-200 year old calculations based on a gas that dosnt exist-thats the ticket

Now in regards to my setup, what energy do you think Elvis took with him when he left the building?

Tinman I really do not know what has gotten into you.  You have become obstinately ignorant and shrill.  As have several others:  I've explained to you repeatedly what would occur in your set-up, and pointed you at suitable references.  If you choose to be deliberately ignorant so be it.  If you choose to act like a jerk at the same time, then again so be it.

[MileHigh]

Tinman you have made some points that have no backing or logic to them.  The example that comes to mind is the false argument that "HHO" was not like an ideal gas and therefore what Mark was talking about didn't apply.  For some reason you were suggesting that the ideal gas laws applied to a different gas, or a gas consisting or only one element, and that was not comparable to "HHO."

Why would you say that?  Hydrogen is a gas like any other gas.  Oxygen the same.  Both follow the "bouncing balls" analogy to the letter.  A mixture of hydrogen and oxygen gas will undergo thermodynamic compression/expansion cycles just like any other gas and behave like any other gas.  These gasses are most likely operating under conditions where the ideal gas law relationships are perfectly linear.  It simply makes no sense to advance the argument that "HHO" is different from H2 of O2 or N2 or just plain air because that is obviously not the case.  I am assuming that your experiment does not push the gasses into any extreme regions where the ideal gas law deviates from linearity.  But even if it did, the "HHO" gas would still behave like any other gas.

MileHigh

[MarkE]

MH Tinman has gotten himself really, really lost.  He'll find out sooner or later just how badly he has deceived himself when he tries to make something based on his misconceptions work.

[MarkE]

I don't think so.

First there is the question that you have NOT answered,, by compressing the gas into a smaller volume does that actually add heat energy or only raise the temperature, there is a difference between the heat energy stored and the temperature of the gas,, basic stuff there so there should be a basic answer,, or maybe all those before you were just really really lost.

The internal energy of the gas is the product:  n (number of molecules) * R (Boltzmann's constant) * T (absolute temperature in Kelvin).  That means if you've got a certain amount of gas, the energy of that gas is proportional to the absolute temperature.  Under static conditions, the product P*V is equal to the internal energy of the gas.

You seem to be forgetting that the temperature of the gas will go up with the decrease in volume and that increase goes along with the increase in pressure,, see work in changes the potential of the system but NOT the stored heat energy, and that energy value is determined at the start and is therefore a static condition that is then set in motion to make a full cycle and returns to the same static condition.

That tangled text really makes no sense in our physical world.  n*R*T is an absolute measure of the internal energy of an ideal gas.  Real gasses come very close to the ideal.  Add energy as heat by any means, or add energy by performing mechanical work and n, and R being constant, T being the only variable, rises.  The work increases: both the pressure and the P*V product.

After all Mark,, if this were either at absolute zero Pa or K it would be at both,, they are a balance,, simple really.

Simple it indeed is.  Unfortunately, you still managed to get it wrong.  The hang-up that you seem to share with Tinman is that you do not recognize that it takes an exchange of work to change the pressure or volume of a fixed amount of gas.  So, while it is perfectly feasible to store 1J of energy at say 20C in an infinite number of different pressure and volume combinations, changing from one combination to another with higher pressure requires work that then results in a greater P*V product (bicycle pump gets hot), or to another with a lower pressure releases work that results in a lower P*V product (can of dusting spray gets cold). 

An adiabatic process would change the pressure / volume relationship without exchanging any energy with the outside world.  That would keep the energy inside Tinman's system constant, no external work would be performed and his premise of performing outside work would fail.  A real process exchanges work with the outside world, specifically, the piston is supposed to do something useful when it moves, the energy to do that cools the gas, just like a can of dusting spray cools when gas is released, and the n*R*T has now gone down inside Tinman's system, meaning that it has given up the energy that performed the external work:  Elvis has left the building.  And again his premise fails.