Subsurface Liters to Bar

[TwoTankers]

I noticed there's a difference in how Subsurface calculates bar from volume of gas used for dive planning, it seems takes into account the pressure rather than just volume divided by tank size.

For example, if I have 2529 liters used and I have my tank set to 24L/200bar, I get 108 bar - I would I have expected 105bar, but close enough.

However, if I set my tank to 12L, 400 bar, I get 249 bar, but would expect 210 bar, which is quite a difference.

I'm curious if somebody knows how the pressure factors into these equations, and if there's an equation for it?

 

[elmo]

There’s a great explanation here

When real gas corrections matter – The Theoretical Diver

thetheoreticaldiver.org

 

[TwoTankers]

There’s a great explanation here

When real gas corrections matter – The Theoretical Diver

thetheoreticaldiver.org

Ah great, thank you.

 

[scubadada]

From the Dive Gear Express website:

Calculating SCUBA Cylinder Capacity | Dive Gear Express®

Or why does my Aluminum 80 SCUBA tank only hold 77 cubic feet of air? ©2018-2020 by Mark Derrick, Gas Blending Instructor at Dive Gear Express ...

www.divegearexpress.com