# REPORT PEDAL OPERATED BATTERY CHARGER.docx

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20 de May de 2023
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### REPORT PEDAL OPERATED BATTERY CHARGER.docx

• 1. 1 CHAPTER -1 INTRODUCTION This is a mechanical device which uses the flywheel to store energy in the form of inertia. Let us explain all the system. In this system we apply extra energy source to start the main motor like electricity or by applying the mechanical energy. In this system a main motor is used to drive a series of pulley and belt arrangement which forms a gear train arrangement which produce a twice/ thrice speed at the shaft of generator. The intriguing thing about this system is that grater electrical can be drawn from the output generator than appears to be drawn from the input drive to the motor. The inertia of flywheel can be increase by increasing the radius of flywheel, weight of flywheel. It also increase if the flywheel weight is concentrated as far out toward the rim of the flywheel as is possible. Firstly the requirement for an effective system needs to be a suitable flywheel with as large a diameter as is practical, and vast majority of the weight needs to be close to rim. The construction needs to be robust and secure as ideally, the rate of rotation will be high as possible, and of course, the wheel needs to be exactly at right angles to the axle on which it rotates and exactly centered on the axle. The main motor is low speed and low voltage input motor and the generator is high speed and high voltage output generator. So when we apply an extra energy to the main motor it start running, which causes to rotate
• 2. 2 the flywheel. When the motor is reaches the highest speed (constant speed) we switch the power by applying the electrical energy generated by the generator. We add the extra thing in the system like transformers, inverter, any extra needed circuits etc. to run the system and take the efficienciable output. The use of fossil fuels and other non-reusable sources of energy must be reduced in order to keep emissions low and alleviate the use of diminishing resources. The idea of human powered generation has been implemented in many different situations. Some examples include hand-crank radios, shaking flashlights, and receiving power from gym equipment (William and Jeffrey, 2012). The use of exercise equipment for a clean source of energy would turn out to be an even more fun experience for participants; it would provide them a means to exercise while indirectly generating power. The pedal operated power generator utilizes human energy to produce electricity quickly and efficiently. The goal is to provide technological solution to problem in the rural world by using detailed opportunity recognition, evaluation, and development of prototype. The prototypes are then turned over to the developing world for manufacturing, distribution and use. Less commonly, pedal power is used to power agricultural and hand tools and even to generate electricity. Some applications include pedal powered laptops, pedal powered grinders and pedal powered water wells. Some third world development projects currently transform used bicycles into pedal powered tools for sustainable development.
• 3. 3 Using human powered generation gives a power source that is not directly derived from natural sources. An example is that a human powered generator can be operated if there is no sun for solar generation, no wind for wind generation, and no water for hydro generation. The power generated from pedal is perfect for remote areas, hilly regions, strategic location, Islands etc., where electricity generation is scanty if not nil. In these situations, a small portable power generating unit would be of great help to provide power supply to charge battery- operated gadgets like mobile phones, lamps, radio, communication devices, etc. It is important to visualize new ways to bring power to the people as population continues to grow and power shortages continue to occur. Much of the power that is provided to people today is done in very un-sustainable ways; new ideas are needed to transit into a post cheap-petroleum era. This design relates to very compact and easily portable power-generating unit, which besides being used as a power generator can also be used as cycle exerciser. It serves dual purpose of power generation and helping the person to maintain physical fitness through exercise of muscles of legs. It can be pedaled or cranked by hand/foot to charge 12 volt batteries and run small appliances.
• 4. 4 CHAPTER – 2 LITERATURE SURVEY 2.1 SHORT HISTORY ON PEDAL POWERED MACHINES Throughout human history, energy has generally been applied through the use of the arms, hands, and back. With minor exceptions, it was only with the invention of the sliding-seat rowing shell, and particularly of the bicycle, that legs also began to be considered as a "normal" means of developing power from human muscles (Wilson, 1986). Over the centuries, the treadle has been the most common method of using the legs to produce power. Treadles are still common in the low-power range, especially for sewing machines. Historically, two treadles were used for some tasks, but even then the maximum output would have been quite small, perhaps only 0-15 percent of what an individual using pedal operated cranks can produce under optimum conditions. However, the combination of pedals and cranks, which today seems an obvious way to produce power, was not used for that purpose until quite recently. It was almost 50 years after Karl von Krais invented the steerable foot-propelled bicycle in 1817 that Pierre Michaud added pedals and cranks, and started the enormous wave of enthusiasm for bicycling that has lasted to the present. Ever since the arrival of fossil fuels and electricity, human powered tools and machines have been viewed as an obsolete technology. This makes it easy to forget that there has been a great deal of progress in their design, largely
• 5. 5 improving their productivity. The most efficient mechanism to harvest human energy appeared in the late 19th century: pedaling. Stationary pedal powered machines went through a boom in the turn of the 20th century, but the arrival of cheap electricity and fossil fuel abruptly stopped all further development (Kris, 2011). Otto Von Guericke is credited with building the first electrical machine in 1660. This form of electricity precedes electromagnetic energy which dominates today. The landscape for today's electricity usage practices bloomed from 1831 to 1846 with theoretical and experimental work from Faraday, Weber and Gauss in the relationship of current, magnetic fields and force. These theories enabled the design modern motors and generators. From 1880 to 1900, there was a period of rapid development in electrical machines. Thus this section reviews the works that has been done on human power generation. 2.2 EARLY DEVELOPMENT Studies in power generation shows that bicycling is one of the most efficient forms of power generation known, in terms of energy expended per person. McCullagh, (1977) gives us an insight into the test conducted by Staurt Wilson using a 24V (at 1800rpm), 20A generator to charge a 12V car battery. A belt-drive was used to connect a 15.5” diameter bike flywheel to a 2.5” diameter pulley that turned the generator. During this test, an average cyclist produced 75W of sustainable electrical power 12V (900rpm) for a period of one hour.
• 6. 6 In 1980, Carl Nowiszewski a mechanical student at the Massachusetts Institute of Technology worked with Professor David Gordon Wilson on a design of a human powered generator which when built will serve as an auxiliary control function in a sail boat in an Atlantic crossing. The energy storage was primarily for automatic steering while the pilot sleep and the pedaling was a way of keeping warm and avoid boredom. The overwhelming problem in the design was the cramped quarters which Nowiszewski eventually solved. And then in 1988, George Alexander Holt III designed a human powered generator using recumbent bicycle technology for use in a sail boat using 6061-T6 aluminum; he built a light weight foldable apparatus. The human power requirement was 120watt at 75rpm (George, 1988). 2.3 RECENT DEVELOPMENT Mohd and others (2013) discussed charkha device in India, stated that spinning wheel horizontally could be rotated by a cord encircling a large, hand- driven wheel where the fiber is held in the left hand and the wheel slowly turned with the right. Holding the fiber at a slight angle to the spindle produced the necessary twist. Jansen and Slob (2003) improved the power generation system known as “Better Water Maker” (BWM) water disinfection system. The BWM was designed for use where water is unsafe for drinking and electricity is scare. The BWM utilizes a manual hand crank to provide power to its pump. They also studied one hand cranking and found that 50w of power could be sustained for up to 30 minutes, which is more than double the 17w required by the BWM.
• 7. 7 As early as 2007, fitness facilities around the world have begun researching applications for converting human power to electricity. The California Fitness facility in Hong Kong was one of the first gym establishments to incorporate human powered machines. Started by French inventor Lucien Gambarota and entrepreneur Doug Woodring, the gym began a program called “Powered by YOU” in which the excess energy generated by members on 13- step cycling and cross training machines is diverted and converted to power lighting fixtures in the gym (Gerard, 2008). Maha and Kimberly (2010), in the Proceedings of ASME 2010 4th International Conference on Energy Sustainability made us to understand that other gyms in the United States began to harness human power as well. The Dixon Recreation Center at Oregon State University (OSU) is one of the many facilities retrofitted between the years 2008 and 2009 by the Clearwater, Florida based company known as ReRev. The company retrofitted 22 elliptical machines at OSU so that the excess energy generated by patrons was diverted to the electric grid. According to the company’s website, “An elliptical machine in regular use at a gym using ReRev technology will generate one kilowatt-hour of electricity every two days.” Dean (2008) revealed that human legs are up to four (4) times more powerful than human arms. On average, a human can sustain about 100W of power through pedaling for an hour but only hand crank about 30Ww of power in an hour. Wilson (2004) demonstrates that a person's oxygen consumption, and
• 8. 8 consequently their potential power output, decreases with age, with the peak of potential power output being between 20-40 years of age According to Jamie and Aaron (2012), Windstream, Convergence Tech and Magnificent Revolution have manufactured stationary pedal powered generators. Typical design included a back-wheel stand that elevates the bicycle and causes the back wheel to come in contact with a smaller wheel that is hooked up to a “bicycle dynamo”and a large battery. K. Ghedamsi- “The flywheel energy storage systems (FESSs) are suitable for improving the quality of the electric power delivered by electric motor. Jamie Patterson, 2004, “The broad goal of this project was the development and demonstration of a complete prototype Flywheel Power System (FPS) and successful proof of the feasibility of this energy storage technology. The next step in development will be final system modifications for the transition from laboratory to field testing, and interface engineering for a field experiment.” Michael Mathew, 2009, “Flywheels serve as kinetic energy storage and retrieval devices with the ability to deliver high output power at high rotational speeds as being one of the emerging energy storage technologies available today in various stages of development, especially in advanced technological areas, i.e., spacecraft’s. Today, most of the research efforts are being spent on improving energy storage capability of flywheels to deliver high power at transfer times, lasting longer than conventional battery powered technologies. Mainly, the performance of a flywheel can be attributed to three factors, i.e., material
• 9. 9 Strength, geometry (cross-section) and rotational speed. While material Strength directly determines kinetic energy level that could be produced safely Combined (coupled) with rotor speed, this study solely focuses on exploring the effects of flywheel geometry on its energy storage/deliver capability per unit mass, further defined as Specific Energy”. Federal energy management program, “Flywheels have been around for thousands of years. The earliest application is likely the potter’s wheel. Perhaps the most common application in more recent times has been in internal combustion engines. A flywheel is a simple form of mechanical (kinetic) energy storage. Energy is stored by causing a disk or rotor to spin on its axis. Stored energy is proportional to the flywheel’s mass and the square of its rotational speed. Advances in power electronics, magnetic bearings, and flywheel materials coupled with innovative integration of components have resulted in direct current (DC) flywheel energy storage systems that can be used as a substitute or supplement to batteries in uninterruptible power supply (UPS) systems. Although generally more expensive than batteries in terms of first cost, the longer life, simpler maintenance, and smaller footprint of the flywheel systems makes them attractive battery alternatives”. Rickard Östergård, “The main conclusion of the literature review was that FESS is a promising energy storage solution; up to multiple megawatt scale. However, few large-scale installations have so far been built and FESS is not a mature technology. Therefore further research and development is needed in multiple areas, including high strength composite materials, magnetic bearings
• 10. 10 and electrical machines. The model was implemented with the necessary control system and tested in a simulation case showing the operational characteristics”. R. Hebner, 2014, “A FESS stores energy in the form of kinetic energy of a spinning mass. Energy transformations from electrical into mechanical and back are carried out by an electrical motor/generator. Potentially, a FESS can offer an essentially unlimited number of charge/discharge cycles. Furthermore, if magnetic bearings and a brushless motors/generator are used, the rotor can be suspended without any mechanical contact. This allows very high rotational speeds and energy densities without affecting the system life”. Seong-yeol Yoo,2009,” Flywheel energy storage systems (FESS) store electric energy in terms of the kinetic energy of a rotating flywheel, and convert this kinetic energy into electric energy when necessary. A FESS is a viable technology for energy storage because it is environmentally safe, can sustain infinite charge/discharge cycles, and has higher power-to-weight ratio than chemical batteries”.
• 11. 11 CHAPTER – 3 METHODOLOGY 3.1 MECHANISM OF OPERATION The Pedal Operated Power Generator (POPG) is a type of generators in which the source of mechanical power is provided by the human effort while spinning a shaft, with its corresponding angular speed (ωhuman) and torque (Thuman). Usually, a sort of mechanical transmission system is needed to adapt these variables into the generators required ones (ωgen and Tgen). Then, this mechanical power is turned into electric power by the generator (Pout gen). Eventually, Poutgen is converted with the aim of being stored (Pin storage), without damaging the storage system. Figure 3.1 Block Diagram of the Generation System
• 12. 12 The principle of using your pedal motion to create the same motion as a motor can be translated to almost any device, and the parts needed are all the same, and in the case of the pedal powered electrical device, the components include: A stationary bike or exercise bike, belt and pulley system, chain drive system, generator, blocking diode, fuse, battery and inverter system. The voltage induced across the terminals of a wire loop when the magnetic flux passing through the loop varies can be calculated using the following equation: E = Nturns Δ∅/Δt Where: E = the voltage induced across the terminals of the wire loop, expressed in volts (V). Nturns is the number of turns of wire in the loop. Δ∅ is the variation in intensity of the magnetic flux passing through the wire loop, expressed in Webers (Wb). Δt is the time interval during which the magnetic flux variation occurs expressed in seconds (s).
• 13. 13 CHAPTER – 4 SYSTEM IMPLEMENTATION 4.1 FLYWHEEL ENERGY STORAGE SYSTEM (FESS) A flywheel stores energy in a rotating mass, depending on the inertia and speed of the rotating mass. According on the need of the grid, the kinetic energy is transferred either in or out of the flywheel. FIG 4.1 Block diagram Flywheel Energy Storage System Flywheel is connected to a machine that works as either the motor or generator. The energy conversion in a FESS is accomplished by the electrical machine and a bi-directional power converter.
• 14. 14 4.2 COMPONENTS There are five mainly five components in flywheel energy storage system:  Flywheel  Motor/Generator  Power Electronics  Magnetic bearings  External Inductor  Battery 4.3 FLYWHEEL Flywheels store energy in a rotating mass of steel of composite material. Mechanical inertia is the basis of this storage method. Use of a motor/generator, energy can be cycled (absorbed and then discharged). Increasing surface speed of flywheel, energy storage capacity (kWh) of unit increased. Figure 4.2: Flywheel and generator pulley arrangement
• 15. 15 4.4 FLYWHEEL ROTOR The energy stored in flywheel is given by E = ½ I ω ^2 where E is the stored kinetic energy, I is the moment of inertia, and ω is the angular velocity. The maximum specific energy is given by where σ is the maximum stress, ρ is the density of the flywheel and K is the shape factor. FIG 4.3 Flywheel Rotor 4.5 Motor/Generator Permanent Magnet (PM) machines have the most advantages, including higher efficiency and smaller size when compared with other types of motors/generators of the same power rating. PM also exhibit lower rotor losses
• 16. 16 and lower winding inductances, which make it more suitable for a vacuum operating environment and the rapid energy transfer of flywheel applications. The motor/generator is designed to be operated at high speed for minimize system size. 4.6 ELECTRIC MACHINE The electrical machine is coupled to the flywheel to enable the energy conversion and charging process. The machine acting as a motor, charges the flywheel by accelerating it and drawing electrical energy from the source. The stored energy on the flywheel is extracted by the same machine, acting as a generator. Common electrical machines used in FESS are  Induction Machine (IM)  Variable Reluctant Machine (VRM)  Permanent Magnet Machine (PM) 4.7 DC MOTOR A direct current (DC) motor is another widely used device that translates electrical pulses into mechanical movement. In the DC motor we have only + and - leads. Connecting them to a DC voltage source moves the motor in one direction. By reversing the polarity, the DC motor will move in the opposite direction. One can easily experiment with the DC motor. For example, small fans used in many motherboards to cool the CPU are run by DC motors. By
• 17. 17 connecting their leads to the + and - voltage source, the DC motor moves. While a stepper motor moves in steps of 1 to 15 degrees, the DC motor moves continuously. Fig 4.4 Internal View of DC Motor In a stepper motor, if we know the starting position we can easily count the number of steps the motor has moved and calculate the final position of the motor. This is not possible in a DC motor. The maximum speed of a DC motor is indicated in rpm and is given in the data sheet. The DC motor has two rotation speeds no-load condition and loaded condition. The manufacturer's data sheet gives the no-load rpm. The no-load rpm can be from a few thousand to tens of thousands. The rpm is reduced when moving a load and it decreases as the load is increased. For example, a drill turning a screw has a much lower rpm speed
• 18. 18 than when it is in the no-load situation. DC motors also have voltage and current ratings. The nominal voltage is the voltage for that motor under normal conditions, and can be from 1 to 150V, depending on the motor. As we increase the voltage, the rpm goes up. The current rating is the current consumption when the nominal voltage is applied with no load, and can be from 25mA to a few amps. As the load increases, the rpm is decreased, unless the current or voltage provided to the motor is increased, which in turn increases the torque. With a fixed voltage, as the load increases, the current (power) consumption of a DC motor is increased. If we overload the motor it will stall, and that can damage the motor due to the heat generated by high current consumption. 4.8 GENERATOR The generator converts the mechanical energy of the turbine to electrical energy (electricity). Inside this component, coils of wire are rotated in a magnetic field to produce electricity. Different generator designs produce either alternating current (AC) or direct current (DC), available in a large range of output power ratings. Most home and office appliances operate on 120 volt (or 240 volt), 60 cycle AC. Some appliances can operate on either AC or DC, such as light bulbs and resistance heaters, and many others can be adapted to run on DC. Storage systems using batteries store DC and usually are configured at voltages of between 12 volts and 120 volts. Generators that produce AC are generally equipped with features to produce the correct voltage (120 or 240 V) and
• 19. 19 constant frequency (60 cycles) of electricity, even when the wind speed is fluctuating. FIG 4.5 GENERATOR 4.9 CHARGE CONTROLLER Battery stores the electric power in the form of a chemical reaction. Without storage you would only have power when the sun is shining or the generator is running. We need battery of 48V. Charge controller has basic function is that it control the source which is to be active or inactive. It simultaneously charge battery and also gives power to the load. The controller has over-charge protection, short-circuit protection, pole confusion protection and automatic dump load function. It also the function is that it should vary the power as per the load demand. It add the both the power so
• 20. 20 that the load demand can fulfill. And when power is not generating it should extract power from battery and give it to the load. We have to choose battery bank size per the load requirement so that it should fulfill the requirement of load for calculating the battery bank size we need to find following data. 1. Find total daily use in watt-hour (Wh). 2. Find total back up time of the battery For increase in battery bank size we need to connect cell in series so that we can get the larger battery bank size. 4.10 BATTERIES Here generally lead acid batteries are used. These batteries are generally low in cost. It helps the vehicle to run not only in day but also in night because it has the capability to store energy which is stored in day time. Battery is used to store energy which will be further used in Peltier module. We will use 12 volt lead acid rechargeable having 6.8 amp rating. The storage battery or secondary battery is such battery where electrical energy can be stored as chemical energy and this chemical energy is then converted to electrical energy as when required. The conversion of electrical energy into chemical energy by applying external electrical source is known as charging of battery. Whereas the conversion of chemical energy into electrical
• 21. 21 energy for supplying the external load is known as discharging of secondary battery. During charging of battery, current is passed through it which causes some chemical changes inside the battery. FIG 4.6 BATTERY This chemical change absorbs energy during their formation. When the battery is connected to the external load, the chemical changes take place in reverse direction, during which the absorbed energy is released as electrical energy and supplied to the load. Now we will try to understand principle working of lead acid battery and for that we will first discuss about lead acid battery which is very commonly used as storage battery or secondary battery. The main active materials required to construct a lead-acid battery are  Lead peroxide (PbO2)  Sponge lead (Pb)  Dilute sulfuric acid (H2SO4)
• 22. 22 A charge controller is needed to prevent the overcharging of the battery. Proper charging of battery will prevent the damage and increase the life and performance of it. A rechargeable battery or storage battery is a group of one or more electrochemical cells. They are known as secondary cells because their electrochemical reactions are electrically reversible. Rechargeable batteries come in many different shapes and sizes, ranging anything from a button cell to megawatt systems connected to stabilize an electrical distribution network. Several different combinations of chemicals are commonly used, including: lead-acid, nickel cadmium (NiCd), nickel metal hydride (NiMH), lithium ion (Li-ion), and lithium ion polymer (Li-ion polymer). FIG 4.7 BATTERY CIRCUIT
• 23. 23 Rechargeable batteries have lower total cost of use and environmental impact than disposable batteries. Some rechargeable battery types are available in the same sizes as disposable types. Rechargeable batteries have higher initial cost, but can be recharged very cheaply and used many times. During charging, the positive active material is oxidized, producing electrons, and the negative material is reduced, consuming electrons. These electrons constitute the current flow in the external circuit. The electrolyte may serve as a simple buffer for ion flow between the electrodes, as in lithium-ion and nickel-cadmium cells, or it may be an active participant in the electrochemical reaction, as in lead-acid cells. The energy used to charge rechargeable batteries usually comes from a battery charger using AC mains electricity. Chargers take from a few minutes (rapid chargers) to several hours to charge a battery. Most batteries are capable of being charged far faster than simple battery chargers are capable of; there are chargers that can charge consumer sizes of NiMH batteries in 15 minutes. Fast charges must have multiple ways of detecting full charge (voltage, temperature, etc.) to stop charging before onset of harmful overcharging. Rechargeable multi-cell batteries are susceptible to cell damage due to reverse charging if they are fully discharged. Fully integrated battery chargers that optimize the charging current are available.
• 24. 24 Attempting to recharge non-rechargeable batteries with unsuitable equipment may cause battery explosion. Flow batteries, used for specialized applications, are recharged by replacing the electrolyte liquid. Battery manufacturers' technical notes often refer to VPC; this is volts per cell, and refers to the individual secondary cells that make up the battery. For example, to charge a 12 V battery (containing 6 cells of 2 V each) at 2.3 VPC requires a voltage of 13.8 V across the battery's terminals. Non-rechargeable alkaline and zinc-carbon cells output 1.5V when new, but this voltage gradually drops with use. Most NiMH AA and AAA batteries rate their cells at 1.2 V, and can usually be used in equipment designed to use alkaline batteries up to an end-point of 0.9 to 1.2V. 4.11 POWER ELECTRONICS Flywheel energy storage system is the three-phase IGBT-based PWM inverter/rectifier. The IGBT is a solid-states device with ability to handle voltages up to 6.7 kV, currents up to 1.2 kA and most important high switching frequencies. The energy conversion in a FESS is accomplished by the electrical machine and a bi-directional power converter. The power electronic converter topologies that can be used for FESS applications are
• 25. 25  DC-AC  AC-AC  AC-DC-AC The widely used configuration of power converters in FESS is AC-DC-AC configuration 4.12 BEARINGS Fig 4.8 Structure and components of a flywheel. Bearings are required to keep the rotor in place with very low friction to provide a support mechanism for the flywheel. Different types of bearing systems are  Mechanical bearing
• 26. 26  Magnetic bearing The widely used bearing technology is magnetic bearing. 4.13 MAGNETIC BEARINGS Magnetic bearings consist of permanent magnets, which support the weight of the Flywheel by repelling forces, and electromagnets are used to stabilize the Flywheel. The best performing bearing is the high-temperature superconducting (HTS) magnetic bearing, which can situate the Flywheel automatically without need of electricity or positioning control system. HTS magnets require cryogenic cooling by liquid nitrogen.  Magnetic bearings consist of permanent magnets, which support the weight of the Flywheel by repelling forces, and electromagnets are used to stabilize the Flywheel.  The best performing bearing is the high-temperature superconducting (HTS) magnetic bearing, which can situate the Flywheel automatically without need of electricity or positioning control system.  HTS magnets require cryogenic cooling by liquid nitrogen. 4.14 EXTERNAL INDUCTOR The high-speed PM machines offer low inductances with low number of stator turns and large operating magnetic air gaps. The low inductances result in High Total Harmonic Distortion (THD) which increases the machine power losses and temperature. Using an external inductor in series with the machine in
• 27. 27 charging mode is necessary to reduce the THD and bring it within an accepted range. 4.15 HOUSING The housing has two purposes  To provide an environment for low gas drag.  For the containment of the rotor in the event of a failure. The housing or enclosure is the stationary part of the flywheel and is usually made of a thick steel or other high strength material. The container holds the rotor in a vacuum to control rotor aerodynamic drag losses by maintaining the low pressure inside the device.
• 28. 28 CHAPTER -5 DESIGN ANALYSIS 5.1 General Design Considerations Generally, the design of this system depends primarily on the ratings of the DC permanent magnets which produce the DC and the required output power. The output power to be produced affects the dimensioning as well as the input parameters like torque, speed, etc. In light of the above constraints, the following design considerations and assumptions has been made for this project design; 1. Sizing and economic considerations: This system is design to compact in consideration of the power requirement as well as reduction in the cost of fabrication. For affordability, the device is relatively small. 2. Safety Considerations: This system is design in such a way that women and children can use it for sustained period of time. It preserves the safety of our immediate environment from noise and air pollution because it’s noiseless and smokeless. Stability of the unit was also considered to ensure that the equipment remains upright at all time, i.e. it should not drift or bend to one direction and it should remain stationary. 3. Ergonomics: The ergonomics aspect has to do with optimizing the physical contact between human and the equipment. Four important areas of bike ergonomics are usually considered: • The strain of the arm and shoulder
• 29. 29 • The muscle support and the position of the lower back • The work of proper pedaling • The crank length 4. Technological consideration: The design of this system is well considered in such a manner that it can be produced within the technology of our immediate environment. 5.2 Frame Design 5.2.1 Choosing Frame Material One of the key elements of the design process of objects under cyclical changing loading is the knowledge of service load history. It is especially important in the case of the bike exerciser in which components are under threat of fatigue damage formation because of the diversified influence of many factors of deterministic and random nature. Bike frames encounter a complex set of stresses which in most cases cannot be calculated by hand. Therefore, in designing a frame, engineers usually makes use of an older design which has proven reliable as a starting point. The frame of the POPG was designed to replicate a typical Schwinn DX bike exerciser with little modifications on the materials used in order to minimize cost and also considering availability of materials. The materials used for exercise bike frames have a wide range of mechanical properties. For most bike builders, steel is the material of choice; steel bikes impart a certain level of confidence in the ability of the bike. It provides the ideal combination of performance and purchase cost.
• 30. 30 They can be inexpensively repaired and have the ability to reveal frame stress injuries before they become failures. When a steel frame breaks, it tends to break slowly rather than suddenly and they have the ability to store and release energy at different degrees of the pedal strokes. 5.2.2 Frame Dimensions To ensure the safety of the user and promote efficient cycling, the dimensions of the bike and cyclist must be taken into account, along with the amount of lateral and vertical clearance needed, in the planning and design of bicycle facilities. The dimensions of a typical bicycle are a handlebar height of 0.75 - 1.10 m (2.5 - 3.5 ft.), handlebar width of 0.61 m (2 ft.), and bicycle length of 1.5 - 1.8 m (5 - 6 ft.). They often provide little traction. The general dimensions adopted for the design was (1200 x 200 x 860)mm (Mn/DOT, 2007). System Force Torque and Power Input This system is designed assuming the average mass of 65kg and pedaling time as 60mins. From reviewed literatures, the pedal input force, torque and power can be computed as below: Input force F = mv/t Input Torque T = F x R
• 31. 31 Input Power P = 2πNT/70 Power Output of the pedal systems Work on a bike exerciser is determined according to the basic work equation Work = Force x Distance The force is a friction resistance (T1) provided by the belt around the large flywheel. This belt can be tightened to varying degree to apply different amount of resistance. One revolution of the flywheel is equal to a distance computed as follows the circumference of the flywheel Distance = 2πr Therefore, the work can now be computed as Work = f * d = T1*2πr To determine the power, we now substitute the number of revolution done in a given period. Power = work / time = T1*2πr * N Pedal Mechanical Efficiency Using the volume of oxygen consumed during exercising, the persons overall or gross mechanical efficiency can be computed as follows:
• 32. 32 Power Output = T1*2πr * N This power output is equivalent to 2.1Kcal/min Pedal Power input = Pinpedal = VO2/min * 5Kcal/ VO2 Expended Power in the Pedal system = Pout - Pin 5.3 Calculation based on sprocket No. of teeth in larger sprocket (𝑇1) = 48 teeth No. of teeth in smaller sprocket (𝑇2) = 13 teeth So Gear ratio will be 𝑇1/𝑇2 =48/13 = 3.7:1 It simply means that it will rotate the flywheel with a speed = (3.7× speed of rear wheel) In a bicycle, gear ratio of pedal sprocket & rear wheel sprocket is usually 2.5:1 So now, In a general case when pedal speed is 30 rpm. Then Speed of rear wheel = 2.5×30 = 75 rpm
• 33. 33 Now again, The speed of flywheel will be = 75× 3.7 rpm = 277.5 rpm Now, we can easily say that by using smaller sprocket on the flywheel end we can get more rpm and so that more energy can be stored because energy stored in flywheel is directly proportional to angular speed. Maximum energy storage in flywheel can be achieved by either increasing the no. of the teeth of larger sprocket or reducing the no. of teeth on smaller sprocket. In this system, gear ratio concept helps us to calculate separate speeds of various parts at different situations .This makes our calculation easier. All above values will be useful in design of flywheel.
• 34. 34 CHAPTER -6 ADVANTAGES  Flywheels are not as adversely affected by temperature changes.  High power capability  Instant response  Working lifespan is high.  They are also less potentially damaging to the environment.  It is possible to know the exact amount of energy stored by a simple measurement of rotation speed.
• 35. 35 CHAPTER -7 APPLICATIONS TRANSPORTATION  Flywheels are used in hybrid and electric vehicles to store energy, for use when harsh acceleration is required or to assist with uphill climbs.  Energy from regenerative braking during vehicle slowdown is stored in flywheels.  In electrical vehicles with chemical batteries as their source of propulsion, flywheels are considered to cope well with fluctuating power consumption. SPACECRAFT  In space vehicles where the primary source of energy is the sun, and where the energy needs to be stored for the periods when the satellite is in darkness.  Initially designs used battery storage, but now FESS is being considered in combination with or to replace batteries.  FESS is the only storage system that can accomplish dual functions, by providing satellites with renewable energy storage in conjunction with attitude control.
• 36. 36 RAILWAY  The reuse of regenerative energy from vehicle braking is the important benefit of using energy storage in electrical railways.  It can increase electrical railway energy efficiency.  Regenerative brake decelerates the train by changing its kinetic energy into electricity and it can be fed back to the power grid in a short time or stored until required.
• 37. 37 CHAPTER -8 PHOTOGRAPHY
• 38. 38 CHAPTER -9 CONCLUSION Flywheel based Energy Storage system used in the vehicles satisfies the purpose of saving a part of the energy lost during braking. Also it can be operated at high temperature range and are efficient as compared to conventional braking system. The results from some of the test conducted show that around 30% of the energy delivered can be recovered by the system. This system has a wide scope for further development and the energy savings. The use of more efficient systems could lead to huge savings in the economy of any country. Here we are concluding that this system got a wide scope in engineering field to minimize the energy loss. As nowadays energy conservation is very necessary thing. Here we implemented Flywheel based Energy Storage system in a pedal operated with an engaging and disengaging clutch mechanism for gaining much more efficiency. As many mating parts are present large amount of friction loss is found in this system which can be improved. Boost is reduced because of friction. Continuously variable transmission can be implemented to this system which would prove in drastic improvement in energy transmissions.
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