Gases and temperature

[Kotcha]

Another question that I've looked for an answer for, but couldn't find.

Do different gases react differently to heating/cooling? I'm asking this because it seems like everyone is using hydrogen for their cooling. And currently I'm trying to heat up this small area, and there's hydrogen in there. Will hydrogen heat up slower than other gases?

[SakuraKoi]

Hydrogen has the highest specific heat capacity (per gram) of any gas (besides Steam). This makes it the best choice for things like Wheezeworts which decrease the temperature of whatever it sucks in by 5°C and it sucks in at most 1000g/s. This makes three Wheezeworths nearly equal to one thermo regulator but without the effect of the wheezeworts heating up in place.

Additionally Hydrogen has the highest thermal conductivity of any gas, making it in return the best choice to cool thermo regulators (the specific heat capacity also allows in return for a bigger temperature gap which increases thermal exchange).

Hydrogen in a way heats up slower because of the highest SHC which requires more DTU being put into the area to achieve the same temperature.

Chlorine could be a choice due to being nearly half the SHC of CO2 (which is the 2nd lowest and around a third of Hydrogen, Cl is 1/5th) but it is worth mentioning that it may take a lot of time due to the Thermal Conductivity being the lowest, by far.

If you can spare a lot of (explosive) energy, then Hydrogen is the choice. If you have time instead, Chlorine or CO2 it is. Mind you depending on the use, Hydrogen is suitable for heat retention.

[thejams]

When heating/cooling a material in ONI, the temperature change depends on 3 things

1) The amount of heating/cooling expressed in DTU (Dupe Thermal Units which equals Joules)

2) The mass of the object in g

3) The Specific heat (capacity) of the material (DTU/g)/°C

You can see the specific heat for each material in its properties panel.  What this number means is basically how many DTU of heating/cool (energy transfer) needs to be done per each gram of the material to change it's temperature 1°C.

Different gasses have different Specific heat attributes:

	Specific Heat
	(DTU/g)/°C
Hydrogen	2,400
Natural Gas	2,191
Sour Gas	1,898
Polluted Oxygen	1,010
Oxygen	1,005
CO2	0,846
Chlorine	0,480

1 hour ago, Kotcha said:

Will hydrogen heat up slower than other gases?

So basically as Hydrogen has the highest Specific heat of all gasses, yes it needs to absorb/release more energy to change its temperature.

This comes in handy for things that have fixed temperature change - like for example a Wheezewort which cools down 1kg of gas every second by 5°C.  This means that for Hydrogen its cooling is (1 000g/s * -5°C * 2,4(DTU/g)/°C) = 12 000 DTU/s (or 12 kDTU/s).  The same Wheezewort in Chlorine would only cool down 2,4kDTU/s.

[SakuraKoi]

9 minutes ago, thejams said:

Different gasses have different Specific heat attributes:

You might like to replace one Polluted Oxygen with "Clean Oxygen", specifically the lower one and adjust the value by -0.005.

To make it even more helpful one might also like to add Thermal Conductivity as well as the ratio of both, even if that is only noteworthy if two elements of the same kind exchange heat (which is actually more often than not the case, especially in an insulated mono-element chamber).

Fun Fact: When Polluted Oxygen becomes "Clean" Liquid Oxygen, no dirt is produced.

[Kotcha]

Thanks guys. Much appreciated.