nicklockard said:
No, it's called "Gibbs Free Energy" and its name is not to suggest that it is "free" as in "costs nothing" but to infer that it is stored chemical potential and enthalpic energy available for chemical or PV work.
Hey, someone's paying attention. (The constant volume case is of course the Helmholtz free energy, and who in his right mind thinks "free energy" means you get something for nothing?!?)
weedeater said:
From what I could glean, it has to do with magnetic fields. They claim they can get more energy out than they put in.
In a previous life I was a (non-VW) quantum mechanic, so let's see if I remember enough to make this make sense ... let's say you have something, could be a ball bouncing in rough terrain, a feather in an updraft, the economy. The behavior of that something depends on what controls it -- its boundary conditions.
Now if you just have boundary conditions you can solve for the energy states that can exist in those BCs (the "eigenfunctions of the Hamiltonian" each with a discrete "eigenvalue"). It turns out that free space behaves like an electromagnetic harmonic oscillator with BCs being "walls" effectively infinitely far apart (actually, stars, galaxies, whatnot affect them), or equivalently an infinite number of harmonic oscillators with periodic BCs. The energy levels (eigenvalues) allowed for each oscillator is (n + 1/2)hv, where the frequency v is set by the spacing of the BCs (this will be key later) and n is the quantum number. Even for n = 0, the energy level is nonzero. There are an infinite number of these oscillators, so infinity times 1/2 hv = infinity, so even in the lowest possible energy state the energy level associated with this "zero point field" is infinity. This unfortunately causes much confusion with those would use the zero point field as an energy source. (In fact, we can't measure this infinity, but since all measurable energy levels are above this infinity we simply subtract off this infinity. Infinity + something - infinity is actually not defined -- it can take any value -- the way we deal with this is called "renormalization".) Anyway, because time and energy (scaled by action) have inverse units, they are related by Heisenberg's uncertainty principle, so we can't know when or if the HOs are at n = 0 (or n = anything else, for that matter, we can only determine the "expectation value"), so the zero point field has fluctuations, random excitations into higher energy states. This is true even in total vacuum at 0 Kelvins (the zero point field is aka the vacuum field)
Since we're blithely subtracting off infinities when we measure anything, is this field observable or a purely theoretical construct? Actually, it can be observed. If you put 2 conducting plates very near each other (micron separation) in a vacuum they will v e r y slightly attract each other. This is called the Casimir effect, and is used by zero-pointers as justification that useful work can be done. Well, if you think about it, the mode density (resonances or eigenfunction solutions to the Hamiltonian which are set by the BCs and
different between the plates compared to outside the plates) and therefore the energy density between the plates will be lower than outside the plates, so the plates will be forced together. Well, why not stack a whole bunch of plates together? In that case only the outermost plates see a difference in mode density so you'll get no more out than from a single pair of plates. (Where does the energy ultimately come from? The thermal or "blackbody" field, in the absence of anything else. You'll still have vacuum fluctuations at 0 K but you can't do any work)
If you didn't quite follow all of that
completely, don't worry, you're doing better than those who would try to extract energy from the zero point field.