Hydrogen bugged?

[TOOK14]

So I'm just posting this here to confirm it's a bug, and I haven't just missed something.  I have this hydrogen condenser to fuel my shiny new rocket, but it's not generating any liquid hydrogen, even though the hydrogen in the room is -254, and hydrogen's condensation point is -252.

In case you are curious, it's ceramic insulated pipe and tile, granite normal pipe for the tiny heating loop, the thermo sensor is set to "under 150c" and the pipe thermo sensor is set to "above -242c"

Spoiler

If anyone can spot a flaw in my design, I'll be very grateful, otherwise this is going on the bug tracker.

[Zarquan]

You actually need to overshoot the condensation point.  I thing this is made to be analogous to enthalpy of vaporization, but some think its so that you don't have as many strobing phase changes.

It will become liquid before you hit -257, but I don't know exactly where it does that.

[crypticorb]

Liquids, gasses, and solids do not change phase for about a 3 degree difference in either direction. This was a quick and dirty method to simulate the latent heat of condensation/vaporization, and to keep liquids/gasses from toggling between states when sitting on that border.

You can see this when trying to melt ice, and the ice will stay ice until it is about 2.4C, instead of melting at -0.6 as it says it should. Same thing with freezing liquids, or condensing gas, you need to bring it below the target temperature by several degrees to reliably condense it.

This is particularly irritating and difficult when condensing hydrogen, because it effectively gives players only a 4C range target to hit to reliably make LH2. Any higher, and the hydrogen won't always condense. Any lower, and the hydrogen will solidify and be worthless.

[Saturnus]

50 minutes ago, Zarquan said:

It will become liquid before you hit -257, but I don't know exactly where it does that.

-254.7C

[TOOK14]

I bumped the pipe thermo sensor 2 more degrees and everything is fine now.  I think maybe there should be some explicit in game mention of needing to overshoot transition temps and by how much, or they should retune the parameters of phase changes so you don't need to overshoot by more than 1 degree C to get a phase change.

[Zarquan]

12 minutes ago, TOOK14 said:

I bumped the pipe thermo sensor 2 more degrees and everything is fine now.  I think maybe there should be some explicit in game mention of needing to overshoot transition temps and by how much, or they should retune the parameters of phase changes so you don't need to overshoot by more than 1 degree C to get a phase change.

If you are using liquid hydrogen for rocket fuel, you do want to overshoot a little unless you have insulation insulated pipes, (the space age pipes) as the liquid hydrogen will heat up in the pipes and could break them.

[TOOK14]

Just now, Zarquan said:

If you are using liquid hydrogen for rocket fuel, you do want to overshoot a little unless you have insulation insulated pipes, (the space age pipes) as the liquid hydrogen will heat up in the pipes and could break them.

I do, and it still heats up and breaks them anyway.  I think insulation is a bit buggy ATM and does not actually have 0 thermal conductivity.  I'm using ceramic instead, at least it's easy to supply repair material.

[Zarquan]

5 minutes ago, TOOK14 said:

I do, and it still heats up and breaks them anyway.  I think insulation is a bit buggy ATM and does not actually have 0 thermal conductivity.  I'm using ceramic instead, at least it's easy to supply repair material.

A second option, if you can manage it, is actually low specific heat pipes.  If you use tungsten pipes through a vacuum (jumping walls with bridges), then the pipes can be reduced to the temperature of the liquid hydrogen.  No heat transferred if they are the same temperature.  But reducing the temperature of a pipe system is hard or expensive.

Also, I believe insulation has a thermal conductivity of 0.00001 or something like that, and it rounds to 0.  Are you using insulated insulation pipes, or just normal insulation pipes?

[TOOK14]

Insulation insulated pipes, and I do use normal granite pipes where I feel they won't be subject to external temps.  Unfortunately, my setup was a learning experience in setting up an advanced rocket silo, so I don't have the room to guarantee thermal isolation in my LO2 and LH2 pipes.  Fortunately, the map I'm on has 2 hot water geysers and 3 cold steam vents, so water is no issue, and my power setup is very good, so I only really care about the wasted building materials and time ATM.

[Coolthulhu]

6 hours ago, TOOK14 said:

I think insulation is a bit buggy ATM and does not actually have 0 thermal conductivity.

The display is buggy. It has the same heat conductivity as abyssalite, which also has non-zero conductivity.

But at some point, Klei changed the display to round the values instead of using scientific notation.

[Doddler]

The display in-game that lists freezing/condensation temperature should probably just show the real temperatures for phase change including the buffer, there's really no reason it couldn't just tell you the actual temperature the shift will happen. It might be initially weird seeing water freeze at -2 and ice melts at 2 in the UI,  but that's how it works in game so there's no reason not to communicate it. It wouldn't even be that bad since some materials have weird shift points already, like methane that turns into a solid at -182 but doesn't melt again until heated back to -161 (where it instantly turns into a gas since that's the vaporization point of methane). Actually I wonder if that's a bug...