What's in a name?
The father of thermodynamics is the perfect mascot for our discussion of realistic futurism
Try as we might, we will never escape the limits imposed by Carnot’s logic. In that regard, [he] haunts us...As our imaginations run wild on fantastical technologies and fantastical futures, the laws of physics will be there to keep us in check.
Before I venture farther, I owe an explanation of the name I’ve chosen for our website and this project: The Ghost of Carnot. The Carnot here referenced is of the "Sadi" persuasion (Sadi Carnot; 1796 to 1832). In terms of his contribution to science, he stands on par with Newton and Einstein and Darwin. You’ve heard of him, right?
Probably not…unless you’ve studied science at the university level. Maybe it’s because his scientific inquiries had military and commercial motivations. Or because he died young. Or because he was French. Or maybe because the field of science he sired — thermodynamics — is harder to understand than apples falling from trees or not as as cool as time slowing down. Who knows? Let’s talk about what he discovered.
The father of thermodynamics
Carnot lived close to the beginning of the Industrial Revolution, when the steam engine was gaining use and prominence in industrial, military, and transport applications. The problem, though, is at that time steam engines were woefully inefficient, converting perhaps only 5 to 10% of the energy content of their power source — typically coal — into useful work. The rest of the energy ended up as waste heat in the ambient surroundings.
Wanting to improve engine efficiency — fundamentally wanting to improve the conversion of source of energy into useful use of energy — Carnot undertook an inquiry of the matter in his book Reflections on the Motive Power of Fire (published in French in 1824). Eschewing a discussion of specific technical innovations that might be brought to bear on the question, he instead focused on what could be the theoretical maximum efficiency of any engine.
What he worked out is as simple as it is profound. He found that the maximum efficiency of any engine — doesn’t matter how it’s designed or what materials it is made from — is equal to one minus a simple ratio: the temperature of the working fluid at the end of an engine cycle (the cold temperature, usually the ambient temperature) divided by the temperature that the working fluid is heated to at the beginning of the cycle (the hot temperature, or the temperature the combusted fuel reaches in the engine).
Carnot efficiency = 1 - TC/TH
Let me say that again. No matter how you design an engine, no matter what it’s made of, no matter what technology is brought to bear on it, it will never produce more mechanical work than that which is determined by the ratio of its hot temperature to its cold. It is a mathematical certainty.
Carnot laid out this certainty 201 years ago, before, I might add, he or anyone else on the planet actually understood what heat was. It took a while, and Carnot died young in the meantime, but his treatise formed the basis for a new field of science — the study of heat, work, and temperature. From his simple and elegant study, the concept of entropy and the second law of thermodynamics directly emerged (also as mathematical certainties), and the whole field of thermodynamics followed.
I’ll spare you the theory and math. But in case you’re struggling with the importance of thermodynamics, I’ll leave you with this testimonial from Einstein:
“[Thermodynamics is] the only physical theory of universal content, concerning which I am convinced, that within the framework of the applicability of its basic concepts, it will never be overthrown.”
Carnot’s logic will haunt our technological ambitions
Getting back to this website’s name, and what fascinates me about Carnot, it’s this. With simple math, logic, observation, and even an imperfect understanding of what he studied, he showed the absolute, unbreakable, mathematically impervious boundaries imposed by this universe on us, on our ambitions, and on our technologies.
Let our imaginations run where they will, let us tinker and innovate, let us bloviate about technological progress. An engine will never do more work than Carnot’s temperature relationship will allow.
We have grown accustomed to thinking about technology as the cavalry coming to save us. If there’s a problem today, well….technology will fix it in a few years. Technology will come to the rescue. We just need to invest in technology, and we’ll find a solution.
That may have been true in the past. It’s not true any longer in many fields of science and technology. In the case of reciprocating engines (ie, your car engine and just about every other engine you've ever come across), the cavalry got here fifty or a hundred years ago. That’s why a Ford Model T got 21 miles to the gallon in the 1920s and today your typical production car gets barely more than that.
None of this should be a surprise to us. We’ve known it all for 200 years now. But we act like we don’t. For one big example, in the past five years, our naive faith in techno-futurism led to the global wasting of hundreds of billions of dollars of public and private capital on hairbrained clean-energy ideas. A basic understanding of the Carnot Cycle and a high-school education in physics should have prevented most of those from ever receiving a second look.
Try as we might, we will never escape the limits imposed by Carnot’s logic. The same is true for Newton’s and Einstein’s and that of many others who have worked to describe the universe as it is and not as they want it to be. In that regard, Carnot haunts us. They all haunt us. As our imaginations run wild on fantastical technologies and fantastical futures, the laws of physics will be there to keep us in check.
The sooner we shed our biases about the future, the sooner we face Carnot’s ghost head on, the smarter and sounder our decisions about the future will be.
I am so glad to read your musings and get an insight into your brilliant mind and ideas. I look forward to reading your thoughts and learn about them in detail. I wish you much success!