A Quick Walk Through Thermodynamics

The reason I am talking about Thermo is that some people just blithely toss off a conclusion that waste must always take place because of the Second Law of Thermodynamics. This conclusion, which has no basis, can immediately be seen to be false, because the Second Law applies to closed systems and the earth is not even close to being a closed system. It is constantly bathed in incoming energy from the sun.

It is common for people to just throw up their hands and decide that Thermo is too difficult for them (or any ordinary human) to understand so leave it to scientists. But I figure that the more people understand the argument I made about how the 2nd Law does not limit design for Zero Waste, the better. And also, I don’t think that Thermo is all that hard to grasp if explained in reasonable terms.

Take a deep breath now and go read the Wikipedia article on the 2nd Law. It reports many funny comments made about the Law. You will feel more like tackling the 2nd Law after reading them.

Thermo has two main laws.(Sometimes a zeroth and a third law are added). The first one is the conservation of energy, which you are probably familiar with. What it says is that there is a thing called energy that has many forms but can always be measured no matter what form it takes. And when it changes its form, the amount of energy in a CLOSED SYSTEM remains the same.

It gets to be important, for our argument, what those forms are. Energy is defined not by pushing and prodding it to see if there is some, but by testing the thing that has it or contains it to see if the energy can be converted into a mechanical form. We define energy as the ability to do work, meaning to be able to push mass, solid things, around. So if we think that some battery has chemical energy inside of it, we test it by converting the energy to electrical energy and then (using a motor for example) into mechanical energy. If we can turn a shaft or gear which can push on a mass and move it, that is the ability to do work. That proves the battery had chemical energy.

Compare this to the handwaving about “energy pathways” in the body that goes by the name of “chi” and moves through “channels” that the mystics talk about. Anyone can use the word energy. Using it is free, even if they have no idea what it means. Anyone can invent words like chi that have no meaning. Physicists challenge themselves with real tests. Can energy be used to do work? If not, it doesn’t exist.

We are still heading to an explanation of the 2nd Law. Basically, the first law says that energy moves around without being lost and the 2nd Law says sure, but what if the energy is broken down into so many tiny pieces that we lose control of it? What if we have no way to line up all those tiny pieces and get the energy back into a form that can be used to do work? When those tiny pieces are atoms and molecules that are bouncing around in all directions, we are screwed. The 2nd Law tells us that in order to get some usable energy back out, we are going to have to lose some of the total energy to some external system which is out of our control.

The classical, and beautiful example of energy conversion is a pendulum. It consists of a weight that swings back and forth on a string. When the weight is at the top of its swing, we say it has potential energy. That is energy based only on its high position. It isn’t actually doing anything we can see except sitting there. But we can make it do work by letting it go to fall or swing. So it had energy. Then at the bottom of the swing, the weight is moving so we can let it hit some mass or a spring for example and get work out of it. So we say it has kinetic energy – the energy inherent in movement. As the pendulum swings, the two forms of energy keep converting into each other over and over. As usual, we ignore the interferences of friction and air. It seems like a simple conversion between two kinds of energy but not all conversions are that simple.

Imagine that we take a heavy steel block and while the pendulum is at its top, we push it right into the path of the weight near the bottom. Now the weight swings down and smashes into the block. The weight stops moving. So where did that kinetic energy go to?
A little of it went into moving the heavy block a tiny bit but most of it – it sort of disappeared. But that can’t be. The first law tells us that doesn’t happen. If we think about it, and do some experiments, we discover the kinetic energy became heat energy. The weight and block both became hotter. The atoms and molecules in the weight and block began to vibrate more strongly. That’s what heat means. This makes sense after all, since the weight had to hit something to stop it. It hit the closest molecules in the block and they hit their neighbors and the neighbors hit their neighbors and so on until the energy was distributed through the whole block. But this is our worst nightmare. We had usable energy and now we have all these molecules moving. How can we ever herd them together and get back our lovely energy and do work with it?

As an aside, we can wonder what would happen if the weight and block weren’t made out of atoms. What if they were made of Superman’s Kryptonium with no internal structure at all? Just solid matter. In that case the weight wouldn’t lose its energy at all. If the block of Kryptonium were too massive to move at all, the weight would bounce off and back to its highest point with no loss of energy. Some real materials have atoms held so rigidly that they can’t easily move. Then collisions work a bit like the Kryptonium. Billiard balls are a common example.

Let’s consider a gas that has heat energy because it’s simpler than solid blocks. The molecules are free to move through space in straight lines until they bounce off another molecule or a wall. Why can’t we just reach in with a tweezer or a needle and select the molecules all moving left, let’s say, and move them into a separate container?

You have to realize how small these molecules are. Let’s say you took a trillion iron atoms and put them into one spot on a glass slide. You still would not be able to see that spot with a normal microscope.

Now, a trillion sounds like a whole lot. You might think it should be visible. But consider this: a trillion dollars is also a large number. But if you distribute it among a bunch of lobbyists and weapons manufacturers and crooked legislators, most politicians wouldn’t be able to see it at all, even if they had an investigating committee to serve as their microscope.

Nowadays we would add in Quantum Mechanics to make it even harder to keep track of molecules. But even before Quantum Mechanics was discovered, physicists knew that molecules were simply too small to keep track of.

So how can we get back any of the heat energy into a form that we can use to do work? The only way we know is to cool down all of the molecules enough so that they line up more than they do now. But in order to do that we need to transfer that heat to something else which is cooler because heat always flows from a hot body to a cooler body. So where is this cooler body? We have to find some external body that can absorb the heat and heat it up a little. In doing this, WE ARE THROWING AWAY SOME OF THE ENERGY IN OUR SYSTEM.

Here’s where my explanation stops, because in order to calculate exactly how much energy has to be thrown away, I would have to derive the exact statement of the 2nd Law and I can’t do that here. Early scientists studying heat resorted to closed cycles of energy movement to figure it out. They figured out that if they defined a quantity they called ENTROPY, and defined it as the amount of heat energy that flows to a cooler body divided by its temperature, they would get an exact measure of how much of the energy was lost when heat energy was moved to a cooler body or other kinds of energy passed through a heat phase.

So is this all just some unimportant theoretical discussion. Not at all. Heat conversion is at the heart of everything we do when using energy. Consider:

  1. Every combustion engine (internal or not) uses the heat of combustion to move a piston. Energy is always lost when combustion heat is converted this way.
  2. Nuclear power plants works by heating water using nuclear energy. Then the heated water has to be converted into electricity by first moving an armature. The 2nd Law tells us how much energy MUST BE sacrificed.
  3. A conventional power plant does the same thing, but the water is heated by fuel combustion.

What we have arrived at up to now is the realization that heat energy can only be captured and used productively by throwing away some WASTE HEAT. Do you see any requirement in here for throwing away some PROCESS WASTE. I don’t. So where does the idea come from that the 2nd Law requires the creation of physical waste?

Perhaps we should look to the work of Ludwig Boltzmann, a nineteenth century physicist. He analyzed the heat of molecules and came up with an amazing conclusion. The concept of entropy, which had previously been defined only in terms of heat transfers, turned out to measure the probability that a collection of gas molecules would be in a particular state. For example, all the molecules inside a balloon are all free to bounce around anywhere in the balloon. A different kind of state would be if all the nitrogen molecules in air were to separate from all the oxygen molecules and occupy different sides of the balloon. Clearly, with time, they would just get mixed up again, but that would be one kind of state converting to another state (exactly how such a state could be created is not important. This is a theoretical discussion. Assume it could happen!) From here it can be generalized that entropy measures the probability of finding any system in a particular state. If all the molecules are jumbled up and sharing all their energy equally, that is the most probable state. If the molecules are held in some compartment, or some of the molecules start with more than their ultimate share of the common energy, that is a low probability or ORDERED state. When the compartment is opened up and the molecules are able to share their energy, they become more mixed up and indistinguishable. The change increases the entropy and therefore the DISORDER.

This then is the common understanding of entropy. It measures the ways in which states of matter are disordered. That is why it always increases. Humpty Dumpty never spontaneously heals his shell and jumps back up on the wall. Inorganic things always break, and become jumbled up. They don’t spontaneously fix themselves. When materials do crystallize and become ordered spontaneously, they give off some extra heat and entropy still increases. Living things can force healing but they consume and metabolize food in order to do it, thus increasing entropy somewhere else. Thus disorder is sometimes interpreted to mean waste production. But the connection is a bit tenuous.

Now let’s ask if the availability of the sun’s energy really, really means that we can always process any kind of disorder, whether a waste or a jumble, and prevent entropy from increasing locally.

How could solar energy be used to put Humpty Dumpty’s egg back together? Here’s how. Collect it all up and grind it into a fertilizer. Add it to the sun’s energy to grow certain plants. Add water that solar energy has distilled into fresh water. Grow a food. Feed it to a chicken. Take the chicken’s egg and put it back on the wall. Voila!

If we are technically clever enough, we usually can find a way to use solar radiation to reverse wasting behavior and we can incorporate that reversal into our entire process and call it a single process. But capturing the sun’s energy doesn’t happen by itself. We need some kind of solar panel or wind turbine or a plant to absorb light and carbon dioxide, create starches and turn into oil after millennia underground. Most of the sunlight falling on the earth is wasted, except for heating. To capture and apply sunlight energy requires machinery or chemical manipulation and that costs money. So there may be a political or commercial decision made that running a process for zero waste is too expensive. On the other hand, most of the time, this is a specious argument that is made only to tear down intelligent design because there are many players who know how to make money from wasting and won’t accept any change that threatens their precious garbage. In fact, intelligent design, is usually much LESS expensive to put to work than dumb design and the money argument is made mindlessly, without any comparison, for the reason pointed out above. Economically powerful players know how to make money from garbage. The last thing they want is to reduce garbage creation, sun energy or no sun energy.

The inescapable comparison is between entropy and garbage. Both are always increasing. Entropy because of a physical law and garbage because of a financial law. The physical law can’t be changed. The financial law can be overturned if people just have the will.

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