Environmental Engineering Reference
In-Depth Information
ment and power electronics and controls. Hydrogenics' HyPM 10 Proton
Exchange Membrane (PEM) fuel cells are used. The power pack is 33 inch-
es long x 40 inches wide x 24 inches high. The low-pressure cell is rated
10-kW net continuous power at 39 to 58 Vdc with a maximum system ef-
ficiency of 56%.
The HyPM 10 fuel cell is fueled by hydrogen. The low-pressure de-
sign ensures quiet operation while maintaining high performance. The
four-wheel forklift uses regenerative braking. Electric energy is stored in
Maxwell Technologies' Boostcap ultracapacitors.
Ultracapacitors have demonstrated a higher recovery of energy from
braking than batteries. They are also lighter, have a longer life and are bet-
ter for the environment. When used with fuel cells in stop-and-go mobility
applications such as forklifts, ultracapacitors provide a burst of power for
lifting acceleration and enable regenerative braking. A small 12-volt bat-
tery is also included to start up the fuel cell.
Since these forklifts had previously been powered by heavier batter-
ies, one issue in the modification was weight. The fuel cell power pack it-
self was relatively easy to integrate into the equipment since it was smaller
and lighter than the lead acid battery system. But, since the battery pro-
vided part of the counterbalance, additional weight was added to provide
enough stability for the forklift.
The fuel cell is supplied with hydrogen from a Hydrogenices HyLyzer
hydrogen refueling station. The HyLyzer produces hydrogen by the hy-
drolysis of water using electricity. Depending on the size of the HyLyzer,
the unit can produce up to 65-kg of hydrogen daily. The HyLyzer refueling
station can refuel a forklift in less than two minutes, much less than batter-
ies can be changed or recharged. The forklift's 4 pound hydrogen storage
capacity is enough for up to eight hours of operation.
The modular design of the HyPM fuel cells allows scaling for higher
power requirements using a variety of configurations, such as series and
parallel systems. Potential applications for the technology include vehicle
propulsion, auxiliary power units (APU), stationary applications including
backup and standby power units, combined heat and power units and por-
table power applications for the construction industry and the military.
HYDROGEN-POWERED AIRCRAFT
The hydrogen economy may be the solution to most of the hydro-
carbon problems of today's oil dependent transport systems. Hydrogen-
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