Hydrogen thruster fuel consumption rate

[Sethiall.dat]

I've been running a few tests with hydrogen thrusters and how long it takes them to deplete a tank when i came across an interesting discrepancy in their fuel consumption rates. My methods aren't super precise (simple stopwatch) but the data i'm getting seems to indicate that depending on what kind of tank the thruster is connected to, it's fuel draw changes. I've only tested this with small grid so far and i've run each test 5 times.

Large thruster Small tank: ~350 L/s
20 second burn time at 100% thrust

Large thruster Large tank ~385.5 L/s
6 minute 55 second burn time at 100% thrust

Is this a bug or a feature?

[herrschaftg35]

I did see on here that hydrogen tanks are limited to how much fuel they can push out.

[BLU REMOTE]

I though hydrogen consumption rate was a super complicated mathematical problem

[Dealman]

Just look at the wikipedia for the exact consumption rates, then you can divide their consumption rate by the hydrogen tank's volume - should give you a decent approximate of how long it will last.

As for the numbers not being exact, could either be a bug or an optimization. Don't really need super mega accurate numbers to simulate the hydrogen usage.

[Spaceman Spiff]

Wikipedia data for SE tends to be really out-of-date. I wouldn't depend on its results for the current SE configuration.

[Buzzard]

Hydrogen consumption rates are available on the Control Panel for the thrusters. Maximum in/output for the tanks is also available. It should be some fairly simple math to determine if your available tanks will be able to supply the number of thrusters you have.
H2 thrusters, like the electric-powered versions, scale in performance when not fully supplied with gas.

[Rox]

The only place you will find guaranteed accurate current data is in the game files themselves.

Look in :

<installation path>\Steam\steamapps\common\SpaceEngineers\Content\Data\CubeBlocks

at file :

CubeBlocks_Logistics.sbc

and you will see the precise specification of the gas tanks...

and in file :

CubeBlocks_Thrusters.sbc

the specification of the thrusters.

But.. the format and units used are not always clear, consistent or sane, because, Keen. ^.^

[Thalyn]

Wait, wait, wait... they separated the files!? Outstanding! I'll have to update my mods.

In terms of consumption, the tank doesn't factor into it. The thrusters have no idea what they're attached to - just how much gas they're able to access on a given tick. This is why they can operate off one or more tanks or straight off one or more generators. The only variables which play in are how much thrust you've got them set to use (in this case, 100%), the MaxPowerConsumption property in their SBC file, and the EnergyDensity in the GasProperties.sbc file.

To that end, the Hydrogen will always have an energy density of 0.001556 per unit (officially the measurement is MWh/litre). The Small Grid, Large Hydrogen Thruster has a MaxPowerConsumption of 0.6 (officially in MW). Due to a fault in Keen's logic, the gas is consumed as if it were measured in joules rather than watt-hours, so the per-second consumption is 0.6 / 0.001556, or ~385.6 units per second.

The Small Grid Hydrogen Tank has a capacity of 160,000, while the Small Grid, Small Hydrogen Tank has a capacity of 7,000. This leads to a full burn time with the same thruster of approximately 415 seconds (6:55 minutes) and 18.2 seconds respectively. Given the closeness of 18.2 to 20 even, I'd suspect your mismatch is simply due to inaccuracy with the stopwatch.

Originally posted by herrschaftg35:

I did see on here that hydrogen tanks are limited to how much fuel they can push out.

This is untrue. Tanks have an unlimited flow rate, both in and out. Even the generators have an infinite flow rate, though in practice that doesn't matter since they only produce a finite amount over time.

[ShadedMJ]

Originally posted by Spaceman Spiff:

Wikipedia data for SE tends to be really out-of-date. I wouldn't depend on its results for the current SE configuration.

That may be getting better. I've seen some edit dates from last month.

[Buzzard]

@Thalyn - Check your tanks again. They now have flow limits both in and out. The CONVEYOR system has no limits, but the tanks, like batteries, have a max in/out. We can see the limits in the control panel. If there were no limit on flow, we could instantly fill tanks using Stockpile.

[Thalyn]

Hmm... any idea as to when that was added? I can't find any reference to ti in the configuration, so if there is such a limit it must be hard-coded into the game. Granted it makes sense that such a limit would exist but I don't recall it, and will need to ensure I haven't accidentally removed it using mods.