H2 From Electrolysis PV Powered

1
H2 From Electrolysis PV Powered

• Ben Dietsch
• MEE 573
• 4/25/02

2
Overall System
H2
02
H20
02
3
Objectives

• Goal Get Johnny Solar to work and back (40
  km) using renewable energy.
• No emissions
• Free ride
• Specific objectives
• Determine power requirements for production and
  compression of H2 for fuel tank
• Determine size of PV array necessary to fill fuel
  tank

4
Fuel Cell Bicycle

• Aprilia Enjoy
• Fuel cell PEM
• 780 g, 600 W
• H2 container carbon fiber
• 2L, 300 bar (4350 psi)
• Total weight 24 kg (53 lb)
• Range 75 km (45 mi.) _at_ 25km/h (15 mph)

5
Electrolysis

• Electrolysis break something apart using
  electricity
• Redox reaction
• Energy 2 H2O(l) ? O2(g) 2 H2(g)
• Electrolyzer efficiency
• 100 3.0 kWh/m3
• 67 4.5 kWh/m3 (typical industrial plants)
• 51 5.9 kWh/m3 (Hydrogen Wind, Inc.)

e-
-

e-
H2
O2
H
e-
O
e-
H
OH-
H2O
6
H2 Production and Compression

• Electrolyzer demand
• 0.1175 m3 (2 L) 5.9 kWh/m3 0.693 kWh
• Isentropic compression
• 25ºC, 1 bar ? 25ºC, 300 bar 0.171 kWh
• 80 efficiency ? 0.218 kWh
• Total energy demand 0.911 kWh

7
PV Modeling

• Visual Basic PV system model (from homework)
• Adequate power (gt 0.911 kWh) in summer w/ 25 ft2

8
Conclusions

• Johnny Solar can get to work and back with just
  25 ft2 PV array, electrolyzer and compressor, and
  a FC bike! (and street smarts)
• Todays system is expensive
• Tomorrows system will give a
• free ride with no emissions.