What is Flywheel Energy Storage?
Flywheel energy storage systems (FESS) work by accelerating a rotor (flywheel) to a very high speed and maintaining the energy in the system as rotational kinetic energy. When energy is extracted from the system, the flywheel's rotational speed is reduced as a consequence of the principle of conservation of energy; adding energy to the system correspondingly results in an increase in the speed of the flywheel.
How to Use the Flywheel Energy Calculator
To calculate the kinetic energy stored in a solid cylindrical flywheel, you need three primary values: the mass of the object, the radius of the wheel, and the angular velocity (measured in revolutions per minute or RPM). Our calculator uses the standard formula for a solid cylinder (I = 1/2mr²) to determine the moment of inertia, and then applies the rotational kinetic energy formula (E = 1/2Iω²).
Simply enter your parameters into the fields above and click calculate. The tool provides results in Joules, Kilojoules, and Watt-hours (Wh), allowing you to understand the power potential of your mechanical battery setup.
Key Components of the Calculation
1. Moment of Inertia (I): This represents the object's resistance to rotational acceleration. For a solid disc, it is determined by mass and radius. The further the mass is from the center of rotation, the higher the inertia.
2. Angular Velocity (ω): This is the speed of rotation. In physics, this is calculated in radians per second. Our calculator handles the conversion from RPM to radians per second automatically.
3. Energy Storage: The energy stored increases linearly with the mass and the square of the radius, but it increases with the square of the rotational speed. This is why high-speed flywheels are far more effective than heavy, slow ones.
Frequently Asked Questions
Why use flywheels instead of chemical batteries? Flywheels offer high power density, rapid charge/discharge cycles, and a much longer lifespan compared to chemical batteries. They are ideal for grid stabilization and uninterruptible power supplies (UPS).
What materials are best for flywheels? Modern high-performance flywheels often use carbon-fiber composites, which have high tensile strength, allowing them to spin at incredibly high speeds without breaking apart under centrifugal force.