Civil Engineering Reference
In-Depth Information
TABLE 10-7
Maximum Specific Energy Storable in a Thin Rim
Flywheel with Various Rim Materials
Maximum Specific Energy
Storable Wh/kg
Wheel Material
Aluminum alloy
25
Maraging steel
50
E-glass composite
200
Carbon fiber composite
220
S-glass composite
250
Polymer fiber composite
350
Fused silica fiber composite
1000
Lead-acid battery
30-40
Lithium-ion battery
90-120
FIGURE 10-21
Flywheel rotor design using two composite rings. (Adapted from the DOE/Oakridge National
Laboratory's prototype design.)
10.10.2
Flywheel System Components
The complete flywheel energy storage system requires the following com-
ponents:
•
high-speed rotor attached to the shaft via strong hub.
•
bearings with good lubrication system or with magnetic suspension.
•
electromechanical energy converter, usually one machine which
can work as a motor during charging, and as a generator while
discharging the energy.
•
power electronics to drive the motor and to condition the generator
power.
•
control electronics for controlling the magnetic bearings and other
functions.
