Established Methods Based on Compression and Cryogenics - Hydrogen Generation, Storage, and Utilization - page 80

Manual Valve, or
Electrical Valve or
In-Tank Regulator

Impact-Resistant
Dome

· Light-weight
· Energy Absorbing
· Cost-Competitive

Ploymer Liner

Carbon-fiber
Reinforced Shell

Reinforced External
Protective Shell

· Light-weight
· Corrosion resistant (hydrogen
embrittlement)
· Permeation barrier
· Cost-Competitive
· Flexible in Size

· Gunfire safety
· Impact safety
· Cut/Abrasion
Resisitance

· Corrosion resistant
(acids, bases)
· Fatigue/Creep/Relaxation
resistant
· Light-weight

FIGURE 5.3 TriShield™ Tank construction. Source : Reproduced with permission from http://www1
.eere.energy.gov/hydrogenandfuelcells/pdfs/32405b27.pdf [5].

external electrical energy. The actual work done to compress a gas is usually
between the theoretical estimations of an isothermal and an adiabatic com-
pression process. The work W required to compress the gas is

V
= ∫ 1

2

W PdV .

(5.11)

V

For an isothermal compression, the temperature of hydrogen is assumed
not to change during the process, and for an ideal gas, the work W T is

W nRTln P
P

2

T = .

(5.12)

1

For a nonideal gas with a Z -factor (Eq. 5.8),

W nZRTln P
P

2

T ≈ ,

(5.13)

1

where V 1 and P 1 are the initial uncompressed volume and pressure, while V 2
and P 2 are the final compressed volume and pressure of hydrogen. For an
ideal gas in a adiabatic compression (no heat exchange with the environ-
ment), it is well known that [7]

γ γ

PV = PV = constant,

(5.14)

1 1