In a lot of the FE blogs and claims you’ll see some “interesting” ideas about “where the energy comes from”. Some people of course avoid that little theoretical bit and purely say “this works” and “give me some money and I’ll show you a video of it”. Alternatively, they may say it worked when they did it before and if you give them some money they’ll build a bigger one that will solve all the world’s problems.
Of course, human languages tend to be circular in their definitions, since each word is defined in terms of others, and it’s only when we’re describing something solid, like a tree, that we can point at it and say “that’s what this word means”. There is thus some question of what we actually mean (or maybe what is understood) when we talk of mass, energy or suchlike where there isn’t something to actually point at. This is maybe worse when we talk about mass and energy, since they are the same thing in a different state.
We can start with the point that energy is the capacity to do work, but that means we also have to define work and also misses the point that when we do work we have the same amount of total energy at the end as when we started – that work is actually done in the course of movement of energy from one place to another and energy itself is neither created or destroyed in any process we know of. All too quickly the conversation gets tied into little knots and the original idea of pinning down where the energy comes from is diverted into needing to also say where it goes to.
I’ll assume that you can look up the terms in the wiki or elsewhere and get a grounding in the ideas of what mass and energy are, therefore. We know what mass is. In a gravitational field a mass has weight and if you use a certain force on it it will accelerate in the direction of the force. Convert that mass into energy (using the formula E=mc²) and instead of a small amount of mass you have a whole lot of energy. That conversion of a small amount of mass into energy powers everything we do. When we burn oil we convert a small amount of mass into the kinetic energy of heat, and so there is a small loss of our initial mass – almost too small a difference to actually measure but we can calculate it. Kinetic energy is energy of movement, and it thus is always moving. It makes sense that any potential energy of any type is actually stored as mass, too, so the spring under tension is just that little bit more mass than the relaxed spring and the weight you’ve just lifted above your head (thus adding gravitational potential energy) has thus also just a bit more mass than when it was on the floor.
We’ve thus reached the point where I can say kinetic energy is stored in movement and potential energy is stored in mass. I’ve also stated that work can only be done when energy moves from one place to another, so the only thing that can do work is kinetic energy.
If we place some kinetic energy into a box (see the starting state in the first picture), then it will move from where we put it. When we’re talking about heat in a gas, then the direction it moves in will be random. Sometimes it will go towards the centre, sometimes it will move away, but since there are far more directions that are away from the centre than directly towards it, after a bit of time t we’ll see this second picture, where although there is a bit more density around the centre area the energy density is less and more diffuse. Pretty-well whatever type of energy we put into an open space, it will spread away from where it’s put in all directions open to it. In these pictures I haven’t put in any constraints except for the outer bounding box, but similar pictures could be produced for any actual situation by applying a bit of maths. Of course, if it’s actually photons we put in to the box instead of some hot air, the diffusion outwards would be a lot quicker.
A bit later on, the initial denser patch has almost gone away. I don’t think there’s much point in adding the final state of just a bit grey all over – if you haven’t seen where this heads by now there’s not much point in reading further.
Basically, when we’re dealing with particles such as air molecules, and the random distribution of collisions and energy transactions, the heat will spread out until there is no measurable difference between any two small sections of the entire space available to that energy. The heat will move from hotter to cooler, and that will always happen. This is the basis of the Second Law of Thermodynamics. Once we have reached the end-state and the energy-density is even, we will no longer be able to measure any differences in temperature and, if we need a temperature difference to get work done, we’re stuffed and no work is possible.
What’s really happening, though, when we’ve reached that point? Those air-molecules are bouncing around just as much as they did before. There is the same distribution of actual kinetic energy across the range whatever volume you care to look at. There is the same pressure, and we know that for a gas, pressure is the sum over a fairly-small (but not infinitesimal) time of the momentum-transfers of the colliding gas molecules. In short, not really a large difference from the way it was at the start with a nice concentrated lump of energy in the middle. If you took a very short time-slice over a small volume (say somewhere around 100ps and a cubic micron with air at STP) you actually wouldn’t be able to say what the temperature or pressure actually was. You might be able to make a rough stab at what it was, but you couldn’t actually be at all sure.
There is still energy moving around in this gas, but there is no longer any net energy movement when you use a reasonably-human scale of time and space. There’s a basic rule in that kinetic energy will tend to spread out so that the space available to it will be evenly filled at the same density, and this can be seen for any situation when the scale is such that it masks the statistical variations over time and space. There’s also the observation that potential energy in a system will tend to drop to the lowest level available. Water finds its own level, and atoms naturally exist in their ground states. These are things we see so often that we don’t really think about it that deeply, except as here where we’re asking that perennial question of “WHY?”.
The question is whether you can still get work out of this body of gas at a single uniform temperature. If you stick to human-scale pistons or fan-blades, no way. For human-scale mechanisms, the 2LoT is going to be right every time. The numbers of molecules we’re dealing with are so gigantic that statistical variations just won’t be useful. If you can get down to scales of mean-free-path in distance and the collision frequency in time, yes there is movement at these scales and so you should be able to harness the obvious movement (kinetic energy) to perform work. If that work comes out as real work, which means that it is either stored as potential energy or goes into kinetic energy, then that volume of gas will be seen to cool, but if it’s virtual work (moving something from one place to another) then no cooling will be seen. For this reason Brownian motion, where the dust or Lycopodium powder is bouncing around all over the place, is just displacement work, averages out to zero, and doesn’t take energy from the gas. Energy is conserved, but work isn’t.
Back to the start again and where the energy comes from in various Free Energy ideas, then. The real answer so far is that it doesn’t because they don’t actually work. That applies to all the designs I’ve seen except for Dan Sheehan’s work and the Lovell device as replicated by RMS. The actual work output from those so far is minute, though. It’s enough to tell me that 2LoT is not exactly correct, and that if we can beat it by a small amount we can maybe push that up to a useful amount of power.
For one that does work, though, there is a large store of energy in the ambient that, if we’re clever enough, we could use. If it’s a real device, then unless it’s harnessing an obvious energy flow in the way that a solar panel harnesses the Sun’s rays, then using the energy flows within the ambient will mean that the device will cool down in the course of putting out power. If you can’t see an obvious energy flow, and it doesn’t cool down, then it probably doesn’t work.
The natural energy flows you need to know about to help you decide are:
Sunlight – about 1.4kW/m² at the top of the atmosphere, and around 1kW/m² at ground level.
RF – in the region of 1W/m² legally allowed. If it’s a lot more than this then maybe you’d want to move somewhere else.
IR from room-temperature – around 1W/m² at 300K.
EDIT: As noted by Phil Hardcastle, the actual blackbody radiation at 300K is 457W/m² at unity emissivity, and here I’ve used the monochromatic power at 10 microns wavelength (peak power). To utilise all that power would need a very wide-band receiver.
Wind – look at some data such as http://www.wind-power-program.com/Library/Turby-EN-Application-V3.0.pdf but at 11m/s there’s about 800W/m² available, and you can harvest up to 59% of that (Betz limit) with a perfect machine. Normally, though 25-50% is more reasonable, so we’re talking maybe 200-400W/m² when it’s pretty blowy.
Water-power – here we have a lot more mass so at 1m/s we’d have 500W/m² and at 10m/s we’d have 1000 times that (yep, 500kW/m², but that’s pretty fast water). Again you can’t harvest all of it.
Heat-flows from hotter to colder objects gets a bit more complex, and can be calculated from the engineering data on heat-transfers, U-values if you’re a builder, and the temperature difference. Since something has to maintain that temperature difference, though, that doesn’t really figure in this discussion.
In case you’re wondering what kicked off this article, it was an email from Sterling (seems I’m still on his list) talking about how we need to repent and that the Noahs Ark ERR generator was in the news again. I sent a reply saying it’s about time he repented and stopped publicising scams such as the ERR, Rosch etc.. If you want to look up the ERR generator, it’s at http://pesn.com/2015/11/18/9602680_James-Schwartz-of-ERR_backs_Remnant-Gathering-initiative/ and though Sterling says he has inside information that is amazing I beg to differ. Check on the actual level of energy available from IR and the smallest 300W one would need around an acre of area to harvest the specified amount. None have ever been sold, none have ever been verified and it’s just another scam asking for money again. These sorts of things annoy me.
I doubt if Stuart or Sterling will read this or whether it will make any difference. Sterling is certain the Rosch bubble machine works and that the ERR generator works, and is rather pleased he’s managed to get rid of most of the sceptics from his site by either editing or deleting comments or by insulting the people who deign to disagree. He did not however manage to point to any of his favourite scams where there is at least one happy customer, though.