Fellow Science Lovers,
Game update: I’m still revising Scribes Emerge. As soon as I’m done, I plan to add another area to the game and sprinkle in some more names. Yours might be among them if you were one of the early reviewers.
My regular farmer’s market has been on break since Dec 21st, so I’ve had many consecutive Saturdays to focus on book edits. I’ve made big redesigns of the final chapters that I think you’ll enjoy when this book finally gets in your hands.
What is Waste Heat?
In A Cartoon Saves the Solar System–my short story in Terrific Tomorrows–you’ll find this passage: “…the Empire gives exotic reactors to the purple planet, raising its power output a million-fold. At first, I think this is awesome, but the waste heat hikes up air temperature to harmful levels.” If you’ve read the story, you may have wondered about this. You probably also suspected I’d write a newsletter article about it.
And you were right!
Let’s use power plants as an example. Most of them generate heat to create steam to turn turbines and produce electricity. This process isn’t fully efficient, though. About 60 to 70% of that heat goes unused and leaks to the environment in different ways. Some rises from cooling towers as steam. Some gets transferred via heat exchangers into a body of water. Some is radiated into the air.
Power plants aren’t the only source of waste heat, though. Cars, factories, refrigerators, electronics, and many other machines all contribute. When we release heat faster than it can escape earth’s atmosphere via thermal radiation, it becomes a problem.
In A Cartoon Saves the Solar System, the Empire gives the purple planet a powerful energy source. The deal sounds enticing: let us build a power plant on your world at our expense and we split the output. You get 10% and we get 90%. (The Empire beams their portion of power back to itself through space.) Admittedly, the percentages sound very skewed, but 10% of a huge output is enough to power their whole world many times over. Who wouldn’t want free and virtually unlimited power?
But this soon creates more waste heat than the world can handle. You see, this planet, being relatively primitive, lacks the infrastructure to remove it. If the Empire had installed the new reactor in orbit above the purple planet, the waste heat would remain in space. Concerned only with gain, the Empire didn’t bother building orbital infrastructure for the purple planet. That would’ve taken more time and expense. Instead, it built everything on the planet’s surface.
It’s Not Just Machines
All living creatures create waste heat. Ever wonder how many people our world could support? Futurist Isaac Arthur answers this in a video I found fascinating: https://www.youtube.com/watch?v=XAJeYe-abUA With the help of infrastructure like arcologies and advanced power sources, he argues earth could comfortably support quadrillions of people… if we could solve the problem of waste heat.
Surprisingly, other concerns aren’t the limiting factors. Physical space? He runs the numbers on how we’d all fit with plenty of room to spare. Food? With hydroponics, we can feed everyone. Power? By building solar arrays in space and sending that power down to earth, we’d avoid most of the industrial heat generation.
But the sheer thermal output of all those human bodies would increase air temperature to over 150F! Arthur points out that we, thermodynamically speaking, are 100 watt generators. The next time you want to compliment someone, don’t say they look like a million bucks. Say they look like 100 watts. 
How would we end up cooking ourselves? Here are the rough numbers:
-2065 kilocalories = 8,640,000 joules (adults metabolize around that much food each day)
-there are 86,400 seconds in a day
-by definition, a watt is 1 joule per second
-8,640,000 joules/86,400 seconds = 100 watts
-so 1,000,000,000,000,000 (1 quadrillion) humans produce 100,000,000,000,000,000 (100 quadrillion) watts, which is almost how much heat the earth absorbs from the sun.
How could we remove waste heat?
We could take the hot exhaust of power plants and pipe it to homes for heating. In fact, some countries already do this. But… this doesn’t remove waste heat from the planet. It merely relocates it to more desirable places.
We could also use waste heat as an input to thermoelectric generators, which I covered in last month’s newsletter. And while this squeezes more use out of power production, this won’t solve a global buildup, either. In fact, the thermoelectric effect is even less efficient than power plants.
So then how would we solve the problem? Sabine Hossenfelder shows some interesting methods in this video: https://www.youtube.com/watch?v=9vRtA7STvH4&t=262s One proposed device, called a “super-chimney”, is a 5km-tall air conditioning unit designed to cool the entire planet! Rather than shifting the heat to another place on earth, it exhausts heat into space. Kind of like sticking a huge window AC unit on the edge of the sky. Remember when your parents told you they weren’t paying to air condition the outdoors? We might actually do that someday.
Would the super-chimney work? It’s inventor made a small prototype that seems functional: https://www.superchimney.org/ We won’t know if it works at scale until someone scrounges up enough money to build the full-size version. You can find detailed specs for how to construct it here: https://www.superchimney.org/build.asp
If any of you decides to have a go at building this, please take lots of pictures and send them to me! 
Writing update: After moving some chapters from the end of Scribes Emerge into Scribes Beyond (book 4), I realized that the cover art for Scribes Emerge no longer made sense–all the content shown on the cover got moved to book 4. So I’ll use that cover for Scribes Beyond instead. That left me with a problem: Now I had no cover for Scribes Emerge. This time around, I created my own. Once final tweaks, I’ll do a cover reveal.
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