Gandhinagar Institute of Technology Guided By: Prof. Amit Patel Active Learning Assignment Topics: “Introduction to Flywheels ” Name Enrollment no Dave rushabh 130120119044 Patel Deep 130120119045 Deepak Kumar 130120119046 Branch : Mechanical Engineering Div: A Guided By: Prof. Amit Patel

Introduction :- A flywheel is a rotating mechanical device that is used to store rotational energy. A flywheel is such a device which is attached to an engine, reciprocating, compressors, pumps etc. Flywheel store energy mechanically in the form of kinetic energy. Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage system.

Flywheel is basically a rechargeable battery. It is used to absorb electric energy from a source, store it as kinetic energy of rotation, and then deliver it to a load at the appropriate time, in the form that meets the load needs. Power in Input electronics Motor Flywheel Output electronics Generator Power out

What does it do? A flywheel at its most basic is a device to store energy. In the case of a flywheel used in automotive applications, it actually serves several purposes. First, it does store energy to help smooth out the torque and power flow of the engine as it runs through its combustion cycles. The flywheel gains energy as the engine accelerates, and stores it as rotational kinetic energy. It then gives some of that energy back to the system to help create momentum to carry the crank and pistons through the compression cycle and help optimize power delivery. Secondly, the flywheel also helps deliver rotational and torsional stability and balance to the engine’s rotating assembly (crank, rods pistons, etc.) in order to help the engine run smoother and reduce wear.

It releases this energy between power impulses, and fluctuations in speed and smoother engine operation. The flywheel is mounted at the rear of the crankshaft near the rear main bearing The flywheel on large, low-speed engines is usually made of cast iron. This is desirable because the heavy weight of the cast iron helps the engine maintain a steady speed. Small, high-speed engines usually use a forged steel or forged aluminum flywheel for the following reasons: (1) The cast iron is too heavy, giving it too much inertia for speed variations necessary on small engines. (2)Cast iron, because of its weight, pulls itself apart at high speeds due to centrifugal force.

Construction of Flywheel :- Flywheels are typically made of steel and rotate on conventional bearings; these are generally limited to a revolution rate of a few thousand RPM. The number of arms depends upon the size of the flywheel and its speed of rotation. But the flywheels above 2-5 meters are usually casted in two pieces. Such a flywheel is known as “ split flywheel”

Types of Flywheels :- Flywheels are of two types as follows Disc type flywheel Rim type flywheel

Otto engine and single cylinder desiel engine

Street car The Connelly Compound Gas Engine: 1888 This is the intended application of Connelly's compound engine to a street-car. The engine is partly hidden behind the large fly-wheel and the variable-ratio friction disc, but the horizontal LP cylinder can be seen to the lower right. The variable-ratio drive was intended to give full control of speed and forward/reverse by one lever. While it was relatively sophisticated, in that the friction wheel contact pressure was varied with the amount of power transmitted, it seems highly unlikely that it could have been made to work for very long.

Applications Typical applications for flywheels include; Dynamic balancing of rotating elements. Energy storage in small scale electricity generator sets. Automotive applications such as clutches.

One Important point A flywheel's momentum can be increased either by making it heavier or by getting it to spin faster. In the past flywheels used for more ambitious energy-storing purposes have tended to be bulky. That is because at speeds above several thousand revolutions per minute (rpm) the materials they were made of could disintegrate. This made them practical for applications in which size does not matter much, such as balancing loads across power grids. They have only found one widespread use in transport: on trains, where they propel some locomotives across gaps in the power rail

Advance and Modern Flywheel Advanced flywheels are also now used for protecting against interruptions to the national electricity grid. The flywheel provides power during period between the loss of utility supplied power and either the return of utility power or the start of a sufficient back-up power system Flywheels have also been proposed as a power booster for electric vehicles. Speeds of 100,000 rpm have been used to achieve very high power densities. Modern high energy flywheels use composite rotors made with carbon-fibre materials. The rotors have a very high strength-to-density ratio, and rotate at speeds up to 100,000 rpm. in a vacuum chamber to minimize aerodynamic losses.

Like the V60 PHEV and unlike most hybrids on the market today, the conventional and unconventional "motors" are separate. In this car, a production turbocharged four-cylinder gasoline engine drives the front wheels while the flywheel KERS unit drives the rear wheels. The operation is fairly simple. Under braking, the wet clutch closes and the KERS drags on the rear wheels to spin up the flywheel. When moving off again, the clutch closes again and feeds the mechanical energy from the spinning flywheel back to the rear wheels to move the car forward. While not currently designed to do so, Volvo says the KERS has enough energy to move the car from a stop. It can already power the car under light throttle to maintain speed.

Use of Flywheel in NASA NASA use the flywheel for deep space propulsion

Benefits in Aerospace Flywheels are preferred over conventional batteries in many aerospace applications because of the following benefits: 5 to 10+ times greater specific energy Lower mass / kW output Long life. Unaffected by number of charge / discharge cycles 85-95% round trip efficiency Fewer regulators / controls needed Greater peak load capability Reduced maintenance / life cycle costs

Single acting cylinder Double acting cylider application of fly wheel

Lets discuss about working of flywheels of heavy vehicles

Conclusion :- Flywheels are one of the most promising technologies for replacing conventional lead acid batteries as energy storage systems for a variety of applications, including automobiles, economical rural electrification systems, and stand-alone, remote power units commonly used in the telecommunications industry. Recent advances in the mechanical properties of composites has rekindled interest in using the inertia of a spinning wheel to store energy.

Abstract In developing countries like India, with rapid growth in the economy, the demand for electricity is also increasing. As the renewable energy percentage increases in the total energy mix, the inherent intermittency and variability of renewable energy sources poses a challenge when these energy sources are integrated. This is where energy storage becomes very critical as it improves the dispatch rate of the electricity generated by renewable energy resource. With the rising demand for reliable, cost-effective, and environmentally friendly energy storage, the Flywheel Energy Storage System (FESS) is quickly coming into its own. This study presents an analysis which shows that using an FESS is a promising alternative in mitigating energy storage problems in decentralized electricity generation projects where an uninterrupted power supply (UPS) is required. With the help of HOMER simulations, we have tried to establish that energy storage through flywheel is a viable option.

Conclusion of research paper:-

Refernce http://www.motortrend.ca/en/car-reviews/sedans/1307-volvo-s60-flywheel-kers-prototype-first-drive/ http://www.fao.org/docrep/010/ah810e/AH810E09.html http://www.boatdesign.net/forums/propulsion/flywheel-energy-storage-systems-32427.html