HUMAN POWERGENERATIONMODEL ADIRA NURANI VAIDYANTHAN1, VIJAYA ILANGO 2* 1, 2Birla Institute of Technology & Science, Bits Pilani, Dubai Corresponding author: [email protected]
bits-pilani.ac.in Abstract: The demand for power isincreasing day by day. Efficient, inexpensive and cleanalternatives need tobe devised. Human Power is oneofthe most efficient alternativesource of energy. To fulfill the demands of the growing populationaneffective and efficient technique to convert mechanical energy to electricalenergy needs to be devised.
This paper discusses the proposal of a new model whichiscost-effective, less complicated andeco-friendly as compared to the existing models. The process describes the conversionof human footsteps to electrical energy by converting linear motion to rotational motion and furtherconverting mechanical energyto electrical energy. The electrical powergenerated can be stored in batteries. This stored energy can be used for a widerange of purposes. Every step given as input counts. Keywords: Mechanical energy, Electrical energy, Linear motion, Rotational motion, Piston,Sphygmomanometer INTRODUCTIONThe human body contains tremendous quantities of energy.
In fact, the average adult has as much energy stored in fat as a one-ton battery. That energy is used for our everyday activities, but if those actions could in turn run the electronic devices we rely then we do need an external source of power. In the past, devices that turned human kinetic energyinto electricity, such as hand-cranked radios, computers and flashlights, involved a person’s full participation.
But a growing field is tapping into our energy without even us noticing it. It is a biologicalprocess that turns fat into energy which is beyond currently available technology.Scientists have an idea that one way to stem climate change might be to harvest tiny amounts of energy in the form of the body’s heat, movement, metabolism and vibrations. In one formof the technology, experts are turning to piezoelectricity, which means “electricityresultingfrom pressure”. Ina piezo-electric material, small amounts of power aregeneratedwhenit is pushed out of shape. As an extraordinary example of what’s now possible with thesematerials, the heart itself couldbe used topower anartificial pacemaker. But as Dr AminKarami at the University of Michigansays, a pacemaker that harvests the energy of theheartbeat itself might operate for a lifetime.
In a recent address to the American Heart Associationin Los Angeles, he pointed out that a sliver of a piezoelectric ceramic onehundredth of an inch thick, powered by vibrations in the chest cavity, can generate almost 10 times the power required to operate a pacemaker. The technology can be used on the outsideof the body as well. Nanotechnologyresearchers are developing the perfect complement to the power tie: a “power shirt” wovenfrom pairs of fibres coated with tiny strips of zinc oxideandgold. As you move, the fibres rub against each other to produce a current. Prof Zhong LinWang, at theGeorgia Instituteof Technology, says that “we could providea flexible, foldableandwearable power source that, for example,would allow people to generate their ownelectrical current while walking. 1 SOURCE POWER PRODUCED (in watts) Basal metabolic rate 80 watts Well – trained cyclist (1 hour) 400 watts Modern racing cyclists 1000-1100 watts Average adult 50 watts Vigorous exercise 150 watts Manual laborer (8-hour work shift) 75 watts Table No. 1:Power Produced by various sources However potential yield of human electric power is decreased bythe inefficiencyof anygenerator device, since all real generators incur considerable losses during the energyconversion process 2.
While attempts have been made to fit electric generators to exercise equipment, the energy collected is of low value compared to the cost of the conversionequipment. 3 The latest techniques which were developed to produce energy from human power includethe following: – 1. Automatic Watches: -Some wristwatches are powered by kinetic energy (called automatic watches), in this case movement of the arm is used. The arm movement causes winding of itsmainspring.
A newer design introduced by Seiko (“Kinetic”) uses movement of a magnet in theelectromagnetic generator instead to power the quartz movement. The motion provides arate of change of flux, which results in some induced emf on the coils. The concept issimply related to Faraday’s Law.
3 Fig 1: Seiko Kinetic Drive Fig 2: Faraday’s Law 2. Piezoelectric Fibers: -Piezoelectriccrystals or fibers generate a small voltage whenever they are mechanically deformed. Vibration from engines can stimulate piezoelectric materials, as can the heelof ashoe, or the pushing of a button. 3Fig 3: Piezoelectric disks generate voltage when deformed 3. Power Keys: -Powerfrom keys pressedduring use of aportable electronic device or remotecontroller, using magnet and coil or piezoelectric energy converters, may be used to help power thedevice. 3 Fig 4: Remote control 4.
Human electric hybrid vehicle: -It is a hybrid vehicle, or more specifically a hybrid human powered vehicle, whose drive train consists of a human being and an electric motor/generator (and one or moreelectricity-storage device(s) such as a battery(ies) or ultra-capacitor(s)). Some vehicles can operate off both human power and be plugged in to operate on battery power. 3 Fig 5: Human electric hybrid vehicle PROPOSED MODEL The main aim of the model is to generate electric current while walking. A large amount ofelectricitycan be generated through this model when arranged on a large scale in places wherepublic pedestrian movements are enormous.14 This setup can be located on foot-stepsor on staircase of any metro or airports, shopping malls, supermarkets where pedestrian movement is the maximum.
This idea is based on the Pascal’s law on pressure and Electromagnetic Induction. It involves the conversion of mechanical energy to electrical energy.15 Air is used to transmit the pressure produced on one end totheother.
Linear motiongets converted to rotational motion. This method is cost effective and can be widely used from charging a battery to powering a room. Compared to the other methods mentioned above thisproposal is simplifiedand does not involve the use of complex sensors or equipments. It is efficient and can act as a source for a wide range of demands.4 • On an average for each step taken =12V * 0.5A = 6Watt.
• 6Watt is produced assuming constant voltage of 12V. The laws involved are: – 1. Pascal’s law on pressure: -Pascal’s law on pressure states that a pressure change occurring anywhere ina confinedincompressiblefluidistransmitted throughout the fluid such that the same changes occur everywhere. Fig 6: Pascal’s law representation 2.
Electromagnetic induction: -Electromagnetic Induction is the production of an electromotive force (i.e. Voltage) across an electrical conductor in a changing magnetic – field. Fig 7: Electromagnetic Induction PROPOSED SCHEMATIC DIAGRAM OFTHEMODEL Fig 8: Detailed sketch MATERIALS REQUIRED • Wooden box – acts as a step and a case for the air bag• Sphygmomanometer – Air bag• Squeezable bulb – it is connected to one of the ends of the sphygmomanometer and isused to pump in air into the air bag• tube wires – is used to pass the air released without any loss• Syringe 60ml – it acts as a piston• Gear arrangement – it is where the conversion of the linear motion to rotational motiontakes place• Generator – is where the mechanical energy gets converted to electricalenergy• Battery – is to store the electricalenergy produced RESULTS ANDDISCUSSION DESCRIPTION OF THE COMPONENTS Fig 9: Human Power Generation Model 1.
Wooden Box – The wooden box acts as a case for the air bag. It is used as a step on whichan external pressure is exerted. The dimensions of the wooden box arelength = 50cm,breadth = 40cm, height = 6cm. The box is made of wood so that it is sturdyenough to withstand even if a strong pressure is exerted.2. Sphygmomanometer -An instrument for measuring blood pressure, typically consisting ofaninflatable rubber cuff which is applied to the arm and connected to a column of mercury next to a graduated scale, enabling the determination of systolic and diastolic bloodpressure by increasing and gradually releasing the pressure in the cuff.
But here, we use it as an air bag which transports the pressure exerted on one end to the other. 73. SqueezableBulb – It is part of the sphygmomanometer which is used to pump in air intotheair bag. It has a knob to adjust the flow rate entering the air bag and can be closed to confine the air within the bag.4.
Tube wires – These wires are inexpensive and prevent the loss of pressure while transporting them from one end to the other.5. Syringe -Thesyringe is used as a piston. It is attached to a small wooden board and the end of the syringe is tied to the clamps using elastic bands. This is done to get an upwardand downward motion like in the piston.
This is the linear motion. Here, Pascal’s law on pressure is applied. The syringe used here has 60ml capacity.6. Gear arrangement – The gear arrangement is where the linear motion is converted torotational motion. The arrangement consists of 2 gears.
First one slightlylarger than the second one.7. Generator – Here the input is rotational motion and the output comes out as electricalenergy. We apply the Electromagnetic Induction principle here.
8. Battery – The electrical energy which comes out as output from the generator can be storedin the battery. This stored electrical energycan be further used as an input for anyequipment. WORKING OF THE MODEL The sketch was made based on the aim of producing energy for each step taken by an individual, not even a single step is wasted here. • As a pressure on the box is applied the air bag releases air due to the force experienced.• Both ends of the sphygmomanometer (which is placed inside the wooden box), isconnected.
One end is connected tothesqueezable bulb andthe other to the wire. This air is transmitted through tube wires to a syringe which acts as a piston (here Pascal’s LawonPressure is applied).• The motion of the piston is controlled by elastic bands which helps it to produce an up anddown motion for every step.• This linear motion is converted to rotational motion using the gear arrangement. The piston and the first gear is attached using a strong copper rod.• The gears are fitted with the help of shafts and the hole on the metalplate is enlarged foreasymovement (through which the shaft passes). The gears are placed at a height to ensure free movement without intervention with the flat metal plate.• The shaft of the second gear is made movable and is attached to the rotor shaft so that as the second gear rotates, the rotor shaft also rotates along with it.
The generator is clampedonto the metalplate; to avoid the rotation of the generator with the shaft.• This rotational motion is given as an input to the generator which produces electricalenergy (here Electromagnetic Induction is applied).• The mechanical energy to electrical energy conversion happens within the generator. This generator can also act as a motor.• This electrical energy is stored in batteries. The wires are soldered on the generator andthen it is connected to the battery. GEAR ARRANGEMENT PLASTIC GEARS– These gears are very light-weight and their cut teeth is perfectly defined. They rotate freelywithout any friction when arranged on a particular height with the help of shafts.
3D PRINTING – An alternative method to design the required design of gear online and print it. Fiber is used here instead of plastic. • A Software called Tinkercad was used to design the gear models on a 3-dimensional workplane.• A .stl code was generated which was converted to a .
gcode and printed using a 3D printer.• Time taken – It took 4 hours to print a 2inch gear.• The gear arrangement is in descending order of size.• As the first gear experiences a 0.5 rotation the next gear will rotate more than 1 completerotation; refer Fig 11.• The gear models can be downloaded and can be edited using this online software.• The unit of measurement used is mm in the software.• The gears need to be arranged in such a way that allthem rotate freely without friction or without getting stuck; refer Fig 10.
• Dimensions of gears are: – Gear 1: h1 = 20mm, d1 = 137.36mm Gear 2: h2 = 30mm, d2 = 100mm Fig 10: Gear arrangement Fig 11: Gear rotation IMPLEMENTATION This setup can be placed in locations where a large population is always present. It can beplaced in malls, airports, schools, colleges, metro stations, fitness facilities etc. 5 Every step counts. A large amount of energy will get stored in the battery for every step. Voltage = 12V,for 1 step = 12V *0.
5A = 6Watt. This setup’s efficiency can be increased with the addition of an additional generator or an extra gear to the gear arrangement. 6 The additionalgeneratorwill increase the input to the generator so more electricity is produced. The gear will increase the rpm so more output is obtained. This experiment can be kept under the entrance carpets. If the setup is placed on a stair more pressure will be applied as the pressure exerted by a humanwhile walking and whileclimbing stairs is different. Hence, if placed on a stair more pressure is exerted.
The wooden box is sturdy enough to support a powerful external pressure exerted onit. The height of the box is 6cm, a small plank is placed to raise the height as the air bag should experience the pressure exerted for the air to flow. A multimeter can be used toanalyze the current obtained for aspecific time period. Analyzing the dataof currentproduced for unit time with the population; refer Fig 12. Fig 12: Population vs electricity RESULT OBTAINED This setup was assembled and kept in the entrance of a flat with approximately 72 householdsfor 2 hours. 7 The power collected was approximately 2V which is the power requirement fora AAA battery.
This AAA battery can be used for remote controls. 8 Fig 13:Setup assembled for testing CONCLUSIONS ADVANTAGES ·It is cost effective compared to the latest and complicated technologies where piezoelectricsensors are used to detect and collect the electrical energy. 9·No externalsource of energy is required other than the human power.12· It ranges from charging your phone to supplying electricity to a household.
13·The entire setup costed around 150aed; which is cost efficient compared to the other techniques mentioned. 10·This setup can be easily implemented anywhere to obtain electricity and can also besupplied as an input source in that environment.· Easy to transport and easy to understand. MAINTENANCE · The pressure in the air bag must be maintained to ensure easy flow of air throughout.· Ensure no leakage in the tube wires to avoid the loss of pressure. 11· Piston and Gear arrangement must be attached properly on a rigid surface.
· The Piston must be lubricated with oil to ensure for easy movement. FUTURE SCOPE This model can be used for a large-scale purpose,· By increasing the size of the syringe more air can be pumped in.· The rpm can be increased by adding more gears of smaller diameter.· Bearings can be used for easy movement of the copper rod and hence increasing therpm giving more output. ACKNOWLEDGEMENTS The authors would like to thank the Director of Bits Pilani Dubai Campus for hisencouragement and support in facilitating the research and other experimental activities.
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