I met Doug Farren in the summer of 2012 at the Launchpad Astronomy Workshop in Laramie, Wyoming. Doug is a popular and successful indie writer of science fiction and fantasy. Check out his Amazon page here. Doug does an occasional column on “The BS in SF.” I really liked his post on thermodynamics and asked if I could re-post it here. Enjoy!

Thermodynamics: I consider it the bane of science fiction. Nothing is 100% efficient and most of the loss in efficiency shows up as heat. A perfect example is something I deal with every day—power production. Nearly every large power plant has a cooling tower and all that vapor pouring out the top is waste heat. How much? About 65% of the energy generated in the reactor or boiler! This waste heat creates a MAJOR problem for science fiction. In order to understand why, let’s take a step back and talk about heat transfer for a moment.

Heat can be transferred in three ways: convection, conduction, and radiation. Convection and conduction require the heat source to be in physical contact with the transfer medium. A spacecraft is isolated from everything else by the vacuum of space which rules out both of these as a means of dumping waste heat. That leaves radiation, which is the transfer of heat through the emission of electromagnetic radiation. This means that if you want to keep your ship cool you need large radiators to dump the excess heat.

If you look at a picture of the International Space Station (ISS), the first thing you will most likely notice are the huge panels extending away from the primary truss. The largest of these are the solar panels that provide the station with electricity. The others are the heat radiators. Damage enough of these and the station will quickly become uninhabitable. Ever wonder why the space shuttle kept its cargo doors open the entire time it was in space? Because the inside of the doors served as heat radiators to keep the shuttle cool. If you’re building a nuclear powered warship equipped with directed energy weapons, you’re going to have to get rid of a tremendous amount of waste heat. To do that, you’ll need a heat radiator with a very large surface area. Now you have a problem. (more…)