Bottled Hydrogen

[Icosahedron]

Just to generate some smiley happy discussion on the board, here are my house rules for using bottled gas - please comment:

Gaseous Hydrogen (or other gas) is stored in metal bottles which weigh 2kg/L at all TL (higher TLs have thinner walls). They cost 20cr/L. These figures are exclusive of contents. Bottles have a minimum size of 5L and a maximum of 1000L (max 1ML/atm for TL4-). Because of the reduced density of the fuel when stored as a gas, it will have a fuel use multiplier dependent on the storage pressure according to the following table:

TL H2 Storage Density g/L Fuel use Multiplier
1 1 atm. 0.0832 858
2 2 atm. 0.1664 429
3 5 atm. 0.416 172
4 10 atm. 0.832 85.8
5 100 atm. 8.32 8.58
6 200 atm. 16.64 4.29
8 300 atm. 24.96 2.86
10 400 atm. 33.28 2.14
12 500 atm. 41.6 1.72
14 600 atm. 49.92 1.43
5+ Liquid 71.4 1.00

So if a device uses LHyd at a rate of 5L/hr, it would use gas from a TL5 bottle at a rate of 5x8.58=42.9L/hr.
The advantage of using gas is that it can be produced at low TL and small quantities can be carried.

Optional Rule:
The minimum size of LHyd tank is 50L, owing to the difficulty of insulating smaller quantities. Note: Power plants smaller than 1m³ cannot subsume the cooling and insulating equipment for LHyd systems. Smaller power plants must add discrete equipment with a mass of M+10kg, where M is the mass of the fuel, and a volume of 5L+F/10 where F is the volume of the fuel.
Example. A vehicle uses LHyd fuel at a rate of 5L/hr. A minimum size LHyd tank will have V=50L, M=3.57kg (fuel) + 3.57+10=13.57kg tank = 17.14kg. and will last for 10 hrs.
A 2 hr bottle at TL 15 will have 14.3L of fuel with V=14.3L and M=28.6kg. This is important if volume needs to be minimised, and 2hrs of fuel is usually adequate.

EDIT: Can someone who understands why tabs don't work in the thread please adjust the table, thanks.

 

[Gadrin]

TL   H2 Storage    Density g/L   Fuel use Multiplier
1    1 atm.        0.0832        858
2    2 atm.        0.1664        429
3    5 atm.        0.416         172
4    10 atm.       0.832          85.8
5    100 atm.      8.32            8.58
6    200 atm.     16.64            4.29
8    300 atm.     24.96            2.86
10   400 atm.     33.28            2.14
12   500 atm.     41.6             1.72
14   600 atm.     49.92            1.43
5+   Liquid       71.4             1.00

EDIT: Can someone who understands why tabs don't work in the thread please adjust the table, thanks.

1. Don't use tabs, use spaces, and
2. wrap the table inside [code][/code] tags and
3. play around with it until it looks right.


>

 

[aramis]

Also, I find it best to edit the table in a monospace font exterior to my browser, then paste it in.

Gadrin: added the close tag for clarity (and edit it to see how to demo tags...)

 

[Icosahedron]

Thanks guys.

Any comments about the use of gas rather than LHyd?
Any comments about the figures?

With hindsight I'm wondering if a mediaeval (TL2) culture could use bellows and a flap-valve or something to achieve twice atmospheric pressure, or whether Leonardo's Renaissance (TL3) culture could quintruple it? I'm fairly sure that by Steam Age, 10 atmospheres should be achievable.