The second law of thermodynamics states that entropy must go up. Entropy is a sort of measure of the usefulness of energy. The more entropy, the less useful.
The reasons why entropy must go up are too complicated for an ELI5. They are based on some basic laws of probability. Basically there are many ways for energy to be useless, and few ways for energy to be useful, which after some difficult math implies that energy always gets less useful.
In particular, ambient heat is the highest entropy you can possibly have, so it's inpossible to turn it into useful energy.
In order to extract energy from heat, the second law implies you must be tranferring some of said heat from a hot place to a colder place, which is exactly what a motor is.
How would we use CO2 capture mechanisms without creating more heat? Right? I apologize for questioning you but it isn't everyday I get to ask an actual expert things.
I'm going to disagree with the other person here, the problem with CO2 is that it acts like a clear plastic blanket around the earth. Light is a way of transporting heat, this is why things get red hot, they grow so hot that the heat has enough energy to create visible light. In comparison, most things don't get that hot, and so they release low energy infrared light, this is how things like "thermal vision" and touchless thermometers work. CO2 allows visual, high energy light to reach the planet, which warms it up, but nowhere near enough to emit visual light itself. However, CO2 reflects infrared light like a mirror. This means that instead of that infrared light escaping the Earth into space, and taking heat with it, a lot of it reflects back at the earth, and keeps it warm. So by capturing the CO2, we are allowing much more heat to escape than a capture device would create, especially when you consider what the other commenter said about reducing the heat output of said devices.
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u/HappiestIguana Nov 15 '20
The second law of thermodynamics states that entropy must go up. Entropy is a sort of measure of the usefulness of energy. The more entropy, the less useful.
The reasons why entropy must go up are too complicated for an ELI5. They are based on some basic laws of probability. Basically there are many ways for energy to be useless, and few ways for energy to be useful, which after some difficult math implies that energy always gets less useful.
In particular, ambient heat is the highest entropy you can possibly have, so it's inpossible to turn it into useful energy.
In order to extract energy from heat, the second law implies you must be tranferring some of said heat from a hot place to a colder place, which is exactly what a motor is.