How to Calculate Flywheel Energy
What is Flywheel Energy?
Flywheel energy storage uses rotational inertia to store and release kinetic energy. It's used for power smoothing and peak shaving.
Formula
Power = dE/dt (rate of energy change)
Step-by-Step Guide
- 1Calculate: E = 0.5 × I × ω² where I is moment of inertia, ω is angular velocity
- 2Energy stored = change in kinetic energy
- 3Power = dE/dt (rate of energy change)
Worked Examples
Input
Flywheel I=100 kg·m², ω=500 rad/s
Result
E = 0.5 × 100 × 500² ≈ 12.5 MJ energy stored
Significant storage capacity
Common Mistakes to Avoid
- ✕Neglecting bearings friction losses
- ✕Over-sizing flywheel (excessive cost and weight)
Frequently Asked Questions
Why use flywheels over batteries?
Flywheels handle high power (charge/discharge rate); good for short-duration storage.
What limits flywheel speed?
Material strength; excessive speed causes material failure. Typically limited to 20-60% ultimate stress.
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