Friday Facts #310 - Glowing Heat pipes

[conn11]

I believe that modern reactors have anti-hydrogen-accumulation measures ?
(Of course, very few currently operating reactors are "modern", the overwhelming majority of them having been built in the 70's...)

The modules against accumulating hydrogen, usually catalytic recombinators (wich recombine H back to H2O) can be added quite easily to containment buildings or other relevant areas.
Here‘s some rather old paper giving a brief overview about special types:

https://inis.iaea.org/collection/NCLCol ... 030457.pdf

[Philip017]

some people cant just be happy with the glowing pipes they need more immersion into the colors and brightness, but i think it looks great, so keep up the good work!

im the guy who brought you immersive laser beam glow.
sorry for improving the game.

lol no, thank you for doing your part to make it better, but still if you got something to contribute, please dont mind me and add your work to it.

[damerell]

Glowing heat pipes make me feeling smth wrong and willing to fix pipes wasting energy for glowing.

Very much this. The way steam pipes don't lose any energy in spite of being apparently just lumps of iron already picks at my suspension of disbelief, but heat pipes that glow orange is pretty absurd. A little window in an otherwise insulated pipe would make more sense (although it's not clear _why_ the pipe would have a window...)

[Light]

Choosing between realism and aesthetically pleasing, I'm going to choose the latter here. Sometimes it's not worth getting too uppity about every little detail when what's presented is perfectly serviceable.

It is nice to see little details being added in general as I didn't expect nuclear to get any sort of revisit.

[Adamo]

I think we're arguing that it would be more aesthetically pleasing to choose the color of a 1000C blackbody over a 2000C blackbody. It's too yellow, right now.

[BlueTemplar]

Glowing heat pipes make me feeling smth wrong and willing to fix pipes wasting energy for glowing.

Very much this. The way steam pipes don't lose any energy in spite of being apparently just lumps of iron already picks at my suspension of disbelief, but heat pipes that glow orange is pretty absurd. A little window in an otherwise insulated pipe would make more sense (although it's not clear _why_ the pipe would have a window...)

Hmm, I tried to find some information comparing copper thermal conductivity to its radiated power, but came up with naught.

So I guess that I'll have to do it myself :

Blackbody radiated power is P = A.σ.T^4, with σ = 5.7x10^-8 W.m^-2.K^-4 (and A = surface area)
So, for 1300 K (=1000 °C), that should be 0.16 MW/m². (Meanwhile, a 300K blackbody environment emits around 460 W/m², so, negligible...)
Note that it's going to be less for (oxidized) copper.
Also note, that it would probably be pretty hard to insulate a pipe like that for long before the insulator itself started to glow !
I really have to read up on those molten metal Russian nuclear subs !

Copper has a thermal conductivity of around 340 W/m/K near 1000 °C.
So assuming a 1m long pipe of copper, one end of which is at 1000°C, and the other at 500°C, the energy flux would be :
340×(1000-500)/1 = 0.17 MW/m²

Note that the two /m² are quite different : in the first case, it's the pipe surface area A ; in the second case, it's its cross-section S !
(For a cylindrical pipe, they would be related by S=(τ/2)×R² ; A=1m×τ×R ; S/A=R/2 ;
for R=1m, S/A=1/2)

Wow, I wouldn't have expected these two to be of the same order of magnitude, but the radiative one to be much smaller !

On the surface, it feels to me that Factorio uses a simulation that ends up with much higher effective thermal conductivities ?

P.S.: That's not even considering thermal conductivities of the ground & air around the pipes, and the convection of air...

[Adamo]

Nice job with the analysis. I am surprised, too: I also would have guessed that the radiative losses were negligible. On the subject of reactors, the liquid-sodium-cooled reactors I know about have a hot plenum that contains the liquid metal, contained in a pool of cold sodium, and then a cold plenum as the outer wall, which contains the cold sodium. When the sodium is passed from the hot tank, out of the hot plenum, into the cool tank, the work is picked up as the sodium cools down. I can't find what material is used as the piping for that transfer, although I know that sodium is considered a good material because it doesn't corrode steel, so maybe steel is used. I don't think liquid copper is considered a good way to go, so this makes the game a bit "unphysical", which is why I find it easy to let go of these concerns. I definitely agree that if you had red-hot sodium contained inside just steel, the steel would equilibriate and eventually glow, as well. My point is simply to inform that in working models, I think the extreme heat is typically contained behind some wall of cooler liquid inside a larger chamber.

[luc]

all the realism doesn't matter as long as its fun and looks good, realism is just a tiny bonus.

Agreed. People often go "but that's not realistic" when that is not actually the goal of a game.

That said, I actually want to comment on this to say the opposite

Namely, one of the reasons I fell in love with Factorio is that there is some level of realism. It made me think about the ingredients of things like plastic, or how one would make power from scratch (burn some water, drive a steam turbine). It was around the time that I had watched some primitive technology videos which I also found fascinating, so the two kind of played together. As someone who is both terrible at and knows nothing about physics, my inner nerd also loves the power system with units that you just don't see in real life (irl everything is this imperial-like kWh unit, which divides or multiplies nicely with exactly nothing, but in-game it's all Joules and Watts and discharge rates that make sense etc.). Maybe it's not realism per se, but it at least made me think about things a little and tickles my inner nerd, as well as being a great game.

[Adamo]

Totally agreed. This is one of the major draws of factorio for many of us, I'm certain. Not all, of course. For example, I was sad when they took away efficiencies, but as long as it's still in the engine, I'm happy to just use my mod to reintroduce them. No game model is going to be perfect, and simplicity is important to provide a good gameplay system. What gets me is that people seem to think these are opposing concepts, though. There's no reason that with a bit of thought we can't come up with a nice optimization for both gameplay and realism in nearly all cases. It just requires a bit of critical thinking and patience and, I dare say, can be strongly aided by consultation with a few good physicists, chemists, and engineers.