Mechanical Energy Storage Guided by: - Presented by: - Mr.S.K. Choudhary DINESH SAHU Lecturer B.E. (VI semester) 0133ME081015

CONTENT INTRODUCTION TYPES OF STORAGE FUNCTION OF STORAGE INTRODUCTION TYPES OF STORAGE FUNCTION OF STORAGE

INTRODUCTION Energy storage is accomplished by devices or physical media that store some form of energy to perform some useful operation at a later time. A device that stores energy is sometimes called an accumulatorenergy accumulator Storing energy allows humans to balance the supply and demand of energy. Energy storage systems in commercial use today can be broadly categorized as mechanical, electrical, chemical, biological and thermal.supply and demand Energy storage is accomplished by devices or physical media that store some form of energy to perform some useful operation at a later time. A device that stores energy is sometimes called an accumulatorenergy accumulator Storing energy allows humans to balance the supply and demand of energy. Energy storage systems in commercial use today can be broadly categorized as mechanical, electrical, chemical, biological and thermal.supply and demand

Three Types of Storage Pumped hydroelectric storage (PHS) Compressed air energy storage (CAES) Flywheels Pumped hydroelectric storage (PHS) Compressed air energy storage (CAES) Flywheels

Pumped Hydroelectric Storage (PHS) Used for load balancing of energy Water is pumped up in elevation during time of low demand Water flows back down during times of high demand Turbines recapture the energy. Used for load balancing of energy Water is pumped up in elevation during time of low demand Water flows back down during times of high demand Turbines recapture the energy.

Pumped Hydroelectric Storage (PHS) 70-85% of electrical energy is recovered Energy loss due to evaporation and Pump/generator inefficiency Currently the most cost effective way to store large amounts of electricity Low energy density calls for large bodies of water Never used in portable technology 1000 kg at 100 ft =.272 kWh

Pumps: On the Grid The Us has 19.5 gigawatts capacity 2.5% of baseload Technology is in use world wide Hundreds of plants around the world Man made reservoirs as well as natural reservoirs

Future Of PHS This energy storage can be used to level the grid for renewable energy Wind power and solar power are not constantly on Using salt mines to increase energy density This energy storage can be used to level the grid for renewable energy Wind power and solar power are not constantly on Using salt mines to increase energy density

Compressed air energy storage (CAES) Large tank is buried underground During times of low demand electricity compresses air During times of peak demand compressed air is heated and released Large tank is buried underground During times of low demand electricity compresses air During times of peak demand compressed air is heated and released

Types Of CAES Adiabatic storage Heat from compression is captured and stored in a solid or liquid Hot Oil C Molten Salt C Heat is reincorporated during release Close to 100% efficiency No utility scale plants Adiabatic storage Heat from compression is captured and stored in a solid or liquid Hot Oil C Molten Salt C Heat is reincorporated during release Close to 100% efficiency No utility scale plants Diabatic storage Heat is lost through cooling Natural gas is burned to reheat compressed air Very inefficient 38-68% Uses 1/2 gas of an all gas plant

More about CAES Can use sandstone layer to hold compressed air USA has good ground for this type of storage Can be used to level load from wind and solar MW Plants Can use sandstone layer to hold compressed air USA has good ground for this type of storage Can be used to level load from wind and solar MW Plants

Compressed air in Cars Zero pollution Motors Stores air at around 300atm Under 35 mph it is zero emissions Over 35 mph uses combustion engine to compress air Runs on many different types of fuel 1 air tank + 8 gal gas= 848 miles Zero pollution Motors Stores air at around 300atm Under 35 mph it is zero emissions Over 35 mph uses combustion engine to compress air Runs on many different types of fuel 1 air tank + 8 gal gas= 848 miles

Fueling/Refueling Flex engine runs off of gas, diesel, alcohol, possibly even vegetable oil Refueling air tank at refuel station about 3 minutes Home refuel unit takes 4 hours, electrical cost $2 3 cents per mile

Future of Air Vehicles Flowair- release in 2010 First needs to pass US safety ratings 6 seats 106 mpg mile range Top speed 96 mph $17500 Flowair- release in 2010 First needs to pass US safety ratings 6 seats 106 mpg mile range Top speed 96 mph $17500

Flywheels Captures energy in a rotating Mass Flywheel is charged using electric motor Electric generator extracts energy

Operation Of Flywheel Energy held in Spinning Rotor (Steel or Carbon composite) Steel rotors can spin at several thousand rpm Carbon composite spin up to 60k rpm Kinetic Energy 1/2mv 2 Energy held in Spinning Rotor (Steel or Carbon composite) Steel rotors can spin at several thousand rpm Carbon composite spin up to 60k rpm Kinetic Energy 1/2mv 2

Bearings Mechanical bearings not practical Friction is directly proportional to speed Magnetic bearings used to minimize friction Rotor is suspended- state of levitation Operates in a Vacuum Mechanical bearings not practical Friction is directly proportional to speed Magnetic bearings used to minimize friction Rotor is suspended- state of levitation Operates in a Vacuum

Superconductors New technology uses high temperature superconductors (HTSC) HTSC operate at C or F Diamagnetism- creates a field of opposition to a magnetic field Hybrid systems use conventional magnets to levitate and superconductors to stabilize New technology uses high temperature superconductors (HTSC) HTSC operate at C or F Diamagnetism- creates a field of opposition to a magnetic field Hybrid systems use conventional magnets to levitate and superconductors to stabilize

Energy Stats Composite FlywheelLi-ion Battery Cycles100,000 to 10 millionAround 1200 Energy Density130 Wh/kg160 Wh/kg CapacityRange from 3 kWh to Max of 133 KWh Equal to 13, Li-ion Over 4 times what is used to power the Tesla Charge Time15 minSeveral Hours Self discharge time“0 run down time”- Years10-20 months Energy ExchangeLimited by generatorLimited by chemical process

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