Flywheel Energy Storage: Increasing or decreasing speed, to add or extract power

By Fouad Sabry

What Is Flywheel Energy Storage

The flywheel energy storage (FES) system works by keeping the energy in the system as rotational energy while simultaneously increasing the speed of a rotor (the flywheel) to an extremely high rate. When energy is removed from the system, the rotating speed of the flywheel slows down as a direct result of the theory of energy conservation. On the other hand, when energy is added to the system, the flywheel's rotational speed rises as a direct result of the principle of energy conservation.

How You Will Benefit

(I) Insights, and validations about the following topics:

Chapter 1: Flywheel energy storage

Chapter 2: Energy storage

Chapter 3: Superconducting magnetic energy storage

Chapter 4: Gyroscope

Chapter 5: Electric motor

Chapter 6: Flywheel

Chapter 7: Regenerative braking

Chapter 8: Magnetic bearing

Chapter 9: Brushless DC electric motor

Chapter 10: DC motor

Chapter 11: Motor-generator

Chapter 12: Revolutions per minute

Chapter 13: Grid energy storage

Chapter 14: Microturbine

Chapter 15: Control moment gyroscope

Chapter 16: Retarder (mechanical engineering)

Chapter 17: London moment

Chapter 18: Hybrid vehicle drivetrain

Chapter 19: Kinetic energy recovery system

Chapter 20: Attitude control

Chapter 21: Flywheel storage power system

(II) Answering the public top questions about flywheel energy storage.

(III) Real world examples for the usage of flywheel energy storage in many fields.

(IV) 17 appendices to explain, briefly, 266 emerging technologies in each industry to have 360-degree full understanding of flywheel energy storage' technologies.

Who This Book Is For

Professionals, undergraduate and graduate students, enthusiasts, hobbyists, and those who want to go beyond basic knowledge or information for any kind of flywheel energy storage.

• Language: English
• Publisher: One Billion Knowledgeable
• Release date: Oct 16, 2022

Book preview

Copyright

Flywheel Energy Storage Copyright © 2022 by Fouad Sabry. All Rights Reserved.

All rights reserved. No part of this book may be reproduced in any form or by any electronic or mechanical means including information storage and retrieval systems, without permission in writing from the author. The only exception is by a reviewer, who may quote short excerpts in a review.

Cover designed by Fouad Sabry.

This book is a work of fiction. Names, characters, places, and incidents either are products of the author’s imagination or are used fictitiously. Any resemblance to actual persons, living or dead, events, or locales is entirely coincidental.

Bonus

You can send an email to [e-mail] with the subject line Flywheel Energy Storage: Increasing or decreasing speed, to add or extract power, and you will receive an email which contains the first few chapters of this book.

Fouad Sabry

Visit 1BK website at

www.1BKOfficial.org

Preface

Why did I write this book?

The story of writing this book started on 1989, when I was a student in the Secondary School of Advanced Students.

It is remarkably like the STEM (Science, Technology, Engineering, and Mathematics) Schools, which are now available in many advanced countries.

STEM is a curriculum based on the idea of educating students in four specific disciplines — science, technology, engineering, and mathematics — in an interdisciplinary and applied approach. This term is typically used to address an education policy or a curriculum choice in schools. It has implications for workforce development, national security concerns and immigration policy.

There was a weekly class in the library, where each student is free to choose any book and read for 1 hour. The objective of the class is to encourage the students to read subjects other than the educational curriculum.

In the library, while I was looking at the books on the shelves, I noticed huge books, total of 5,000 pages in 5 parts. The books name is The Encyclopedia of Technology, which describes everything around us, from absolute zero to semiconductors, almost every technology, at that time, was explained with colorful illustrations and simple words. I started to read the encyclopedia, and of course, I was not able to finish it in the 1-hour weekly class.

So, I convinced my father to buy the encyclopedia. My father bought all the technology tools for me in the beginning of my life, the first computer and the first technology encyclopedia, and both have a great impact on myself and my career.

I have finished the entire encyclopedia in the same summer vacation of this year, and then I started to see how the universe works and to how to apply that knowledge to everyday problems.

My passion to the technology started mor than 30 years ago and still the journey goes on.

This book is part of The Encyclopedia of Emerging Technologies which is my attempt to give the readers the same amazing experience I had when I was in high school, but instead of 20th century technologies, I am more interested in the 21st century emerging technologies, applications, and industry solutions.

The Encyclopedia of Emerging Technologies will consist of 365 books, each book will be focused on one single emerging technology. You can read the list of emerging technologies and their categorization by industry in the part of Coming Soon, at the end of the book.

365 books to give the readers the chance to increase their knowledge on one single emerging technology every day within the course of one year period.

Introduction

How did I write this book?

In every book of The Encyclopedia of Emerging Technologies, I am trying to get instant, raw search insights, direct from the minds of the people, trying to answer their questions about the emerging technology.

There are 3 billion Google searches every day, and 20% of those have never been seen before. They are like a direct line to the people thoughts.

Sometimes that’s ‘How do I remove paper jam’. Other times, it is the wrenching fears and secret hankerings they would only ever dare share with Google.

In my pursuit to discover an untapped goldmine of content ideas about Flywheel Energy Storage, I use many tools to listen into autocomplete data from search engines like Google, then quickly cranks out every useful phrase and question, the people are asking around the keyword Flywheel Energy Storage.

It is a goldmine of people insight, I can use to create fresh, ultra-useful content, products, and services. The kind people, like you, really want.

People searches are the most important dataset ever collected on the human psyche. Therefore, this book is a live product, and constantly updated by more and more answers for new questions about Flywheel Energy Storage, asked by people, just like you and me, wondering about this new emerging technology and would like to know more about it.

The approach for writing this book is to get a deeper level of understanding of how people search around Flywheel Energy Storage, revealing questions and queries which I would not necessarily think off the top of my head, and answering these questions in super easy and digestible words, and to navigate the book around in a straightforward way.

So, when it comes to writing this book, I have ensured that it is as optimized and targeted as possible. This book purpose is helping the people to further understand and grow their knowledge about Flywheel Energy Storage. I am trying to answer people’s questions as closely as possible and showing a lot more.

It is a fantastic, and beautiful way to explore questions and problems that the people have and answer them directly, and add insight, validation, and creativity to the content of the book – even pitches and proposals. The book uncovers rich, less crowded, and sometimes surprising areas of research demand I would not otherwise reach. There is no doubt that, it is expected to increase the knowledge of the potential readers’ minds, after reading the book using this approach.

I have applied a unique approach to make the content of this book always fresh. This approach depends on listening to the people minds, by using the search listening tools. This approach helped me to:

Meet the readers exactly where they are, so I can create relevant content that strikes a chord and drives more understanding to the topic.

Keep my finger firmly on the pulse, so I can get updates when people talk about this emerging technology in new ways, and monitor trends over time.

Uncover hidden treasures of questions need answers about the emerging technology to discover unexpected insights and hidden niches that boost the relevancy of the content and give it a winning edge.

The building block for writing this book include the following:

(1) I have stopped wasting the time on gutfeel and guesswork about the content wanted by the readers, filled the book content with what the people need and said goodbye to the endless content ideas based on speculations.

(2) I have made solid decisions, and taken fewer risks, to get front row seats to what people want to read and want to know — in real time — and use search data to make bold decisions, about which topics to include and which topics to exclude.

(3) I have streamlined my content production to identify content ideas without manually having to sift through individual opinions to save days and even weeks of time.

It is wonderful to help the people to increase their knowledge in a straightforward way by just answering their questions.

I think the approach of writing of this book is unique as it collates, and tracks the important questions being asked by the readers on search engines.

Acknowledgments

Writing a book is harder than I thought and more rewarding than I could have ever imagined. None of this would have been possible without the work completed by prestigious researchers, and I would like to acknowledge their efforts to increase the knowledge of the public about this emerging technology.

Dedication

To the enlightened, the ones who see things differently, and want the world to be better -- they are not fond of the status quo or the existing state. You can disagree with them too much, and you can argue with them even more, but you cannot ignore them, and you cannot underestimate them, because they always change things... they push the human race forward, and while some may see them as the crazy ones or amateur, others see genius and innovators, because the ones who are enlightened enough to think that they can change the world, are the ones who do, and lead the people to the enlightenment.

Epigraph

The flywheel energy storage (FES) system works by keeping the energy in the system as rotational energy while simultaneously increasing the speed of a rotor (the flywheel) to an extremely high rate. When energy is removed from the system, the rotating speed of the flywheel slows down as a direct result of the theory of energy conservation. On the other hand, when energy is added to the system, the flywheel's rotational speed rises as a direct result of the principle of energy conservation.

Table of Contents

Copyright

Bonus

Preface

Introduction

Acknowledgments

Dedication

Epigraph

Table of Contents

Chapter 1: Flywheel energy storage

Chapter 5: Distributed generation

Chapter 3: Superconducting magnetic energy storage

Chapter 4: Gyroscope

Chapter 5: Electric motor

Chapter 6: Flywheel

Chapter 7: Compressed air car

Chapter 8: Regenerative braking

Chapter 9: Magnetic bearing

Chapter 10: Brushless DC electric motor

Chapter 11: Motor–generator

Chapter 12: Motor–generator

Chapter 8: Peaking power plant

Chapter 14: Microturbine

Chapter 15: Control moment gyroscope

Chapter 16: Retarder (mechanical engineering)

Chapter 17: London moment

Chapter 18: Hybrid vehicle drivetrain

Chapter 19: Kinetic energy recovery system

Chapter 20: Attitude control

Chapter 21: Flywheel storage power system

Epilogue

About the Author

Coming Soon

Appendices: Emerging Technologies in Each Industry

Chapter 1: Flywheel energy storage

The flywheel energy storage (FES) system works by keeping the energy in the system as rotational energy while simultaneously increasing the speed of a rotor (the flywheel) to an extremely high rate. As a result of the concept of energy conservation, the rotational speed of the flywheel slows down as energy is removed from the system; conversely, adding energy to the system causes the flywheel's speed to rise in direct proportion to the amount of energy introduced into the system.

The majority of FES systems rely on electrical energy to speed up and slow down the flywheel, however researchers are working on developing devices that directly utilise mechanical energy.

A flywheel that is held in place by rolling-element bearings and that is coupled to a motor-generator is an example of a common setup. It is possible to enclose the flywheel and the motor–generator in a vacuum chamber in order to lessen the amount of friction and the amount of energy that is lost.

In flywheel energy-storage devices of the first generation, the energy is stored in a massive steel flywheel that rotates on mechanical bearings. Carbon-fiber composite rotors are used in more recent systems because they have a higher tensile strength than steel and can store a much greater amount of energy for the same mass.

Magnetic bearings are occasionally used in place of mechanical bearings because of their lower coefficient of friction.

Because of the high cost of cooling, low-temperature superconductors were quickly abandoned as a potential material for use in magnetic bearings. High-temperature superconductor (HTSC) bearings, on the other hand, have the potential to be cost-effective and might potentially increase the amount of time during which energy could be stored affordably. The implementation of hybrid bearing systems is most likely to occur initially. In the past, high-temperature superconductor bearings have struggled to offer the required lifting forces for bigger designs. However, these bearings have shown to be adept at supplying the necessary stabilizing force. As a result, load support in hybrid bearings is provided by permanent magnets, while high-temperature superconductors are utilized to stabilize the bearing. Due to the fact that superconductors are ideal diamagnets, they are able to perform very well when it comes to stabilizing the load. If the rotor makes an attempt to move out of its centered position, a restoring force that is caused by flux pinning will bring it back. This property of the bearing is referred to as its magnetic stiffness. It is not possible to employ totally superconducting magnetic bearings for flywheel applications because rotational axis vibration may develop owing to poor stiffness and damping, which are intrinsic difficulties of superconducting magnets.

Because flux pinning is such a crucial component in the process of supplying the stabilizing and lifting force, the HTSC can be manufactured considerably more readily for FES than it can be for other purposes. As long as the flux pinning is sufficiently strong, HTSC powders may be molded into any shape imaginable. Before superconductors can provide the full lifting force for a FES system, one of the ongoing challenges that needs to be overcome is finding a way to suppress the decrease in levitation force and the gradual fall of rotor during operation that is caused by the flux creep of the superconducting material. This is a challenge that has to be overcome before superconductors can provide the full lifting force.

When compared to other methods of storing electricity, FES devices have extended lives (lasting decades with little or no maintenance) and are relatively low in cost; Here m is the integral of the flywheel's mass, and n_{m} is the rotational speed (number of revolutions per second).

The maximum possible specific energy that can be extracted from the rotor of a flywheel is primarily determined by two factors: the first is the geometry of the rotor, and the second is the qualities of the material that is being utilized. This connection may be represented as for rotors made of a single material that are isotropic.

{\displaystyle {\frac {E}{m}}=K\left({\frac {\sigma }{\rho }}\right),}

where

E is kinetic energy of the rotor [J], m is the rotor's mass [kg], K is the rotor's geometric shape factor [dimensionless], \sigma is the tensile strength of the material [Pa], \rho is the material's density [kg/m³].

The optimal value for the form factor of a flywheel rotor, which is the greatest attainable value, is K=1 , It is something that can only be accomplished via the use of the theoretical constant-stress disc shape.

A constant-thickness disc geometry has a shape factor of {\displaystyle K=0.606} , while for a rod of constant thickness the value is {\displaystyle K=0.333} .

A thin cylinder has a shape factor of {\displaystyle K=0.5} .

For the majority of flywheels that have a shaft, the shape factor is below or about {\textstyle K=0.333} .

A shaft-less design has a shape factor similar to a constant-thickness disc ( {\textstyle K=0.6} ), This allows for a density of energy that is twice as high.

For the purpose of energy storage, it is preferable to choose materials that have a high strength but a low density. Flywheels that are considered to be state of the art often make use of composite materials for this reason. The strength-to-density ratio of a material may be represented in Wh/kg (or Nm/kg); some composite materials are capable of achieving values that are higher than 400 Wh/kg.

There are a few recent flywheels that have rotors constructed up of composite materials. For instance, the carbon-fiber composite flywheel developed by Beacon Power Corporation is one example.

The tensile strength of the rotor is one of the key constraints that are placed on the design of flywheels. In general, the disc's strength determines the maximum speed at which it can be spun and the amount of energy that the device is able to store. (Since the flywheel's maximum speed at which it can spin without rupturing will decrease if its weight is increased without a matching increase in its strength, adding weight to the flywheel will not result in an increase in the total amount of energy that it is capable of storing.)

When the tensile strength of the outer binding cover of a composite flywheel is exceeded, the cover will fracture, and the wheel will shatter as the outer wheel compression is lost around the entire circumference, releasing all of its stored energy at once; this phenomenon is commonly referred to as a flywheel explosion due to the fact that wheel fragments can reach kinetic energy comparable to that of a bullet. Flywheels are used in a variety of applications, including automobiles, aerospace, and military vehicles Composite materials that are wound and glued in layers have a tendency to disintegrate quickly, first into small-diameter filaments that entangle and slow each other, and then into red-hot powder; a cast metal flywheel flings off large chunks of high-speed shrapnel. Composite materials that are wound and glued in layers have a tendency to disintegrate quickly.

The binding strength of the grain boundaries in a polycrystalline molded metal determines the failure limit for a cast metal flywheel. Particularly susceptible to fatigue and the development of microfractures is aluminum, which may occur as a result of repetitive low-energy straining. It's possible that angular forces may lead pieces of a metal flywheel to either detach entirely and bounce erratically around the inside, or they could cause those portions to bend outward and begin tugging on the outside containment vessel. The remainder of the flywheel is very out of balance at this point, which might result in the premature failure of the bearings due to vibration and the abrupt shock fracture of huge portions of the flywheel.

Traditional flywheel systems call for the use of robust containment tanks as a safety measure; nevertheless, this results in an increase in the overall mass of the device. The energy that is released when something fails may be reduced by utilizing a gelatinous or encapsulated liquid as the inner housing lining. This will cause the liquid to boil and absorb the energy that is released when anything fails. Despite this, many clients of large-scale flywheel energy-storage systems choose having the flywheels buried in the ground to prevent any material from escaping the containment vessel.

Flywheel energy storage devices that make use of mechanical bearings may lose anywhere from 20 to 50 percent of their energy in the space of only two hours.

Flywheels, when installed in cars, also serve the function of gyroscopes since the order of magnitude of their angular momentum is often comparable to that of the forces that are exerted on the moving vehicle. When turning or driving over uneven terrain, this attribute may be harmful to the vehicle's handling qualities; driving along the side of a steep hill may cause wheels to partly lift off the ground while the flywheel battles lateral tilting forces. On the other side, this trait may be used to keep the automobile balanced in order to prevent it from rolling over during quick bends. This would ensure that the vehicle would not be thrown over.

When a flywheel is utilized only for the impact it has on the attitude of a vehicle, rather than for the storing of energy, we refer to that particular kind of flywheel as a response wheel or a control moment gyroscope.

By putting the flywheel inside a properly adjusted set of gimbals, the resistance of angular tilting may be nearly totally avoided. This enables the flywheel to keep its original orientation without harming the vehicle (see Properties of a gyroscope). This does not eliminate the complexity caused by gimbal lock; thus, a balance must be struck between the number of gimbals and the amount of angular flexibility available.

The axle that runs through the middle of the flywheel functions as a single gimbal, and if it is aligned vertically, it enables the flywheel to yaw through a full 360 degrees in a horizontal plane. Driving uphill, for example, calls for a second pitch gimbal, while driving along the side of a steep embankment calls for a third roll gimbal. Both of these scenarios need additional gimbals.

A free-movement gimbal mounting inside of a vehicle needs a spherical volume for the flywheel to freely spin inside. The flywheel itself may be of a flat ring form, but the mounting itself must be a spherical volume. When left to its own devices, a vehicle's spinning flywheel would gradually precess in the direction of the Earth's rotation, and it would precess even farther in vehicles that travel great distances across the curved spherical surface of the Earth.

Because of precession, which occurs as the Earth spins, a full-motion gimbal presents extra challenges in terms of how to convey power into and out of the flywheel. This is because the flywheel has the ability to turn entirely over once every day. Full freedom of rotation would need slip rings for power conductors to be placed around each gimbal axis, which would further add to the complexity of the design.

To make better use of available area, It's possible that the gimbal system has a design that restricts its range of motion, utilizing shock absorbers to cushion unexpected, quick movements within a set number of degrees of out-of-plane angular rotation using shock absorbers, after which progressively coercing the flywheel into conforming to the prevailing orientation of the vehicle.

This results in a reduction in the amount of area available for gimbal movement around a ring-shaped flywheel, to a compact cylinder with a thicker wall, encompassing for example ± 30 degrees of pitch and ± 30 degrees of roll in all directions around the flywheel.

Having two flywheels that are connected together and rotating in opposing directions at the same time is an alternate method for solving the issue. They would have an angular momentum of 0 in total and there would be no gyroscopic effect caused by them. When there is a difference in momentum between the two flywheels that is anything other than zero, the housing for the two flywheels will display torque. This is one of the problems with this proposed approach. To ensure