Posted at 12.11.2018
When we hear the word, 'green energy' the first things which come in your thoughts are solar power panels, wind turbines, hydroelectric power plus some may consider waste materials incineration as a means of producing energy. Albeit as an island, few of us stop and reflect on the huge energy probable that there surely is in the waters bordering our island. Influx energy is little by little being used round Europe, particularly in countries facing the Atlantic. Malta falls in the medium range of wave heights gives the possibility to utilize small wave energy generators which can make a considerable amount of energy.
Through this task our aim is to create a device which harnesses wave energy and changes it into electricity. The look must be cost effective, with no or limited contribution to aesthetic pollution and most importantly useful. Through this job we hope that people not only succeed in developing a design which works but also think of a design that has a potential to be advanced further in order to be utilized as a means of producing electrical energy in the Maltese Islands.
After initially, choosing what we try to do, our first step was to analyse wave shape, wave habits and wave levels round the Maltese Islands. Within our initial steps, we looked into current types of influx energy generators in order to obtain a clear picture to what has already been found globally. The final design which we came up with was that which we codenamed 'Sea Saw' the name itself expresses the good thing about the design. The design swings on the waves and as it swings electricity is produced. As part of our task, we also completed a survey with the purpose of analyzing the general public awareness and belief on wave energy. Another part of the task was interviews with Jamie Taylor, to be able to access learn about wave energy in European countries.
Being constantly reminded that traditional methods of energy development are adding to serious environmental problems, government authorities across the world are seeking new means of producing electricity. Malta is not any exception. By 2020, at least 20% of Malta's energy development has to result from renewable options.
As a reply to the urgent dependence on pollution-free power era, the energy sector was pressured via a renovating process, which sees its beginning towards renewable energy. One of the new emerging establishments in the renewable energy industry is the influx energy industry. However the technology is relatively new and currently not financially competitive with aged systems such as wind energy, the interest from government authorities and industry is continuously increasing. A significant feature of sea waves is their high energy denseness, which is the best among the renewable energy resources.
The notion of converting the energy of ocean surface waves into useful energy varieties is not new. You will find techniques that were first patented as soon as 1799 by Girard & Kid in France.
Consider an average ocean influx, wavelength 200m, wave height 1. The wave is 10 ms-1. This inflatable water particles progress and down just as a typical wave however they also move sideways. Both of these motions combine to provide a circular action. The water debris have both kinetic energy and gravitational energy. Both can be captured by suitable devices. A difficult computation of the influx energy are available by assuming a square wave as shown:
The square influx has wavelength 200m and amplitude 1m. The wave entrance is assumed to be 1m large. The crest of the wave is above the standard level while the trough is below. The centre of gravity changed by this particular as it moves from crest to trough, is 1m. The quantity of water, transferred is the volume of the crest.
F is found using the equation c = f», f = c/» = 10/200 = 0. 05 hZ
Power = Energy x Frequency = 106 x 0. 05 = 5 x 104 Watts
For a sinusoidal influx, the power is about half approximately that of a rectangular wave. Hence, the energy of a sinusoidal influx is equivalent 25 x 103 W. Besides, potential energy, a wave also has kinetic energy. This will be add up to the kinetic energy according to the theory of simple harmonic action. Therefore, total ability, KE + PE = 5 x 104 Watts. Used, the actual electric power made will be smaller anticipated to energy losses and inefficiencies of the complete system.
Wave energy occurs in the motion of water close to the surface of the sea. A wave is produced when the wind, effectively drags at this particular as it blows across. As the wind flow becomes stronger and the distance over which it blows boosts, a lot more energy the waves have. As waves address the coastline, they begin to lose energy through friction with the seabed and finally break on the shoreline. Thus the higher amount of energy is situated in waves in the deeper well-exposed waters just offshore. All the various types of energy devices, take energy out of the motion of this inflatable water nearby the surface by changing the action of the waves into motions that electric power generators to create electricity.
Being an island, were an totally surrounded by sea. Statistical data from WERMED Malta shows that Malta is well placed to make use of the power stored in waves, that happen to be normally of medium elevation to produce electricity. Amount 1: Average Significant Influx Height and Influx Route (Source: WERMED Malta)
After initially choosing the theme of the task, an activity of designing the ultimate wave generator was undergone. We posted the properties that the final design should have. Then we started out designing designs including the following:
Figure 2: Requirements of the Wave Generator
In all different designs were taken into account. Each design was assessed and its benefits and drawbacks were outlined. Through this process, our goal was to come up with the best possible design which isn't only practical but also efficient.
The first design was inspired by the shake torch device which features a magnet passing through a coil as it passes it creates a power current. As the float bobs on drinking water (when there are waves), the magnet moves through the tube, moves through the coil and creates an electric current. The pipe is connected to a capacitor which stores the existing. This design was ruled out, since it isn't enough for large scale energy generators.
Figure 3: Design 1
The influx generator is flexible such that it moulds itself on the wave. At any time, one of the three barrel like floats is found at the trough and the other two barrel like floats are found at crest. At the same time, weights in the medial side arms strike piezo plates which convert mechanical stress into electrical energy and a magnet steps through the coil to be able to produce electricity by electromagnetic induction. The look is anchored from only 1 cylinder to permit free rotation to face current wave path. The rotation is aided by triangle shaped set ups mounted on the barrel like floats.
The two exterior barrels would be customized so they will have both weight and buoyancy. The center barrel will be modified therefore the total weight of the center barrel is twice that of 1 of the exterior barrels.
This design was ruled out after analyzing each facet of the design. The vitality production tube associated to piezo was deemed highly inefficient because piezo disks, only produce millivolts and so not suitable to produce energy in large range projects. The vitality creation system associated to gearbox system was regarded inefficient because there would be huge energy loss associated, to turning the gear wheels. Alternatively, we observed that there is potential in energy production using electromagnetic induction, thus we established our project on this form of energy creation.
Figure 4: Design Nos. 2
Figure 5: Design Nos. 3
This design consisted of a tube, with coil wound around and a magnet moving inside. As the magnet rolled, through the coil, electricity is produced. Waves cause, the pipe to shift to 1 part and the magnet as a result gains more acceleration as it steps towards the end of the tube. This design was ruled out because as the magnet shifts to the finish of the pipe and strikes the other area, energy is lost as it hits the end of the pipe. Thus, the design is considered inefficient credited to significant energy losses.
In designing, the ultimate design a design which has continuous movement was organized.
The influx generator is an extended, narrow package pivoted and anchored in the middle so that, as you end goes up, the other falls. One end continues on the influx crest and the other falls with the trough of the influx. When one end, rises the smooth inside the tube falls and transforms the turbine which is connected to the coil. As soon as it reaches the end of the pipe, the flap closes and forces the fluid to stream backwards and the liquid takes the road along the other side. As it moves downwards, it becomes the other turbine, which is connected to the magnets. The turbine and magnets submit the opposite route, making electricity by electromagnetic induction.
Figure 6: Design Nos. 4
Building the model
Copper Wire - Coil
In practice, the ocean Saw should be half wavelength predicated on average worth, so that one end rests on a crest and the other end rests on a trough. Its axis should be parallel to the action of the influx, it is perpendicular to the influx front.
It should be anchored from the centre, to the ocean foundation. The anchor should be versatile such that it can modify itself to drinking water level/level.
String was wound round the magnets shaft. It was spun by pulling the string. Voltage was checked out by using an AC Voltmeter. Average reading was About 2. 3 Volts.
The same reading was obtained with an oscilloscope. Peak was 2 cm, pattern was 8 cm long. Configurations were 2 volts per cm. Time base was 10 ms per cm. These match a top voltage of 4 volts. RMS (Main Mean Square Voltage) was 2. 8. Periodic Time was 80 ms. Occurrence was 12. 5 Hz.
Theoretical voltage was computed the following:
Emf made by each length of the coil when slicing the field lines is given by
Where B = Magnetic Flux Density = 0. 04 T
l = Diameter of Magnet 4. 5 cm = 0. 045m
v = Average velocity
To find Average Velocity:
R = Average Radius of coil 5 cm = 0. 05m
F = Regularity of Rotation 12. 5 Hz (obtained from oscilloscope)
At any time the coil is lowering the magnets at 4 different tips. The coil got 70 converts.
Total Optimum Voltage = 5 Volts
This agrees with the value from the oscilloscope.
In the initial design, the gates were 20 cm high (Bottom to hinge). These started to hit the edges of the tank and didn't open properly. These were reduced to 13 cm. Weights by means of heavy nut products were attached to them using silicon sealer, in order to reduce the gate's buoyancy since they are manufactured from Perspex.
The fish tank was filled up with water. Wave movements was simulated by rocking the fish tank manually.
Gates didn't open up properly and there was leakage of water. Water didn't flow the entire circuit but started to flow backwards. Normal water did not have sufficient space to move to at the ends. The look was emended by extending the tank incorporating a circular pathway.
Friction at the bearings tended to make the magnet disc and coil to rotate in the same path. This was because of the common shaft on which they were turning. The common shaft was found in order to stabilize the system. On a more substantial model, the utilization of common shaft can be averted.
Backward movements was halted by placing a ratchet with each water turbine.
Hinge moves in direction of the pedal but not backwards.
Use turbines instead of drinking water mill.
Smaller gates in order that they open better.
Larger and longer Perspex package.
Instead of drinking water, use a denser liquid such as mercury.
Water mills will need to have less flaps so that they do not reduce the flow of drinking water.
The aim of the study was to review people's perception on influx energy and their knowledge. A duplicate of the survey which was distributed is situated in the appendix. The majority of those who answered the survey placed wave energy as the second best way of producing electricity in Malta using green energy sources. That is understandable since actually when observed in context wave energy continues to be in its first stages to be used as the primary way of producing electricity thus it should be implemented together with other forms of alternative energy.
There was a considerable majority who clarified that they never heard of wave energy. Given that renewable energy has been on the agenda going back five years and influx energy seem to learn of it, it appears that the federal government and other authorities are not giving wave energy its anticipated importance nor are they considering its potential at least in small levels. The lack of importance given to wave energy is also shown through the results obtained for question 4.
The majority understand that wave energy has a potential but at exactly the same time accept that further research should be completed before it is applied on a huge scale. This is the general response both for question 5 and question 3.
Question was mainly misunderstood and the few survey respondents who known the question correctly accepted that influx energy can have a poor environmental impact, which may be minimised by building a wave generator which is more green and has a smaller visual impact.
The survey results show that individuals are not well informed and this point must be studied into consideration in developing the reasonable stand. The purpose of the good stand should not be merely to inform the public on our job but also on influx energy all together including its advantages and its disadvantages.