Wave energy converter Report
This exercise can be done through two important lines; the first most important exercise is to assess the available resources into details and the second exercise is to develop the most efficient and very reliable wave energy converters (WECS). After coming up with all fundamental resources that are necessary for wave energy conversion then examine the technologies behind the conversion of the wave energies starting with its historical point of view. The idea of wave energy is very old but due to the shortages of oil and environmental impact, modern research has to chip in. Currently researches are coming up with many different fields of research. On the other hand, new technologies are arising and will continue to get into the market.
0Introduction 1 2. 0 Literature Review 3 3. 0 Theory 12 4. 0 Apparatus and Methods 12 5. 0 Observations and Results 15 6. If you add or delete sections remember to renumber the sections. 0 Introduction 1. 1 The problem The increased dependency on fossils as a source of energy has resulted to too many effects to most of the countries and world at large. These effects include; greenhouse effect, exhaustion of the reserves, political conflicts which is accelerated by the exhaustion of the reserves, climate changes and reduced development of the global economy due to fluctuation of oil price. On basis of this grounds, most of the government in the countries that are very cautious of their environment have made a mile on measures to curb the level of carbon fuels dependency. This implies that wind waves that is transmitted on earth can be referred to as solar energy that is highly concentrated.
The potential of wind waves to produce energy has been recognised for so long. This untapped resource was first attempted in the late days of 18th century but thorough and intensive exploration of wave energy conversion and development was started in 1973 after world experienced first oil crisis. According to historical perspective of wave energy, there are two lines that are necessary for wave energy to be fully fledged renewable; the first step is presenting the most spatial and temporary variability in order to assess the particular areas of great interest and determine the quantified potentials, the second step is developing a reliable and more efficient wave energy converters (WECs). Currently thorough research in areas of wave energy conversion is being done by many countries in the world.
Some countries like United Kingdom (UK) has developed and tested the ‘Wells’ turbine. Oscillating wave convertor is advantageous in such that it has only one moving part, which is the turbine. The simplicity of the device is of significant benefit when it comes to marine environment. On the other hand, the main disadvantage of this device is that the building is large, and it is constructed of the concrete in the ocean. Therefore, to counter the challenge in it is by producing precast concreate or in other words to use fabricated steel caissons that can easily be constructed on the dry land and then later get floated into the right position. This is a clear indication that waves that are in deep waters propagate without having any interaction with the bottom part of the sea.
This kind of interaction come out clearly in two processes; refraction and shoaling. These two processes modify properties of waves. When these waves reach the shoreline, then their energy is in the dissipated part through breaking in the part that are reflected back by the sea. Nevertheless, in a given area, let’s say bays that are protected by the land at the end, diffraction of the waves can easily occur. The average wave energy sites present values between 20-70 kWm-1 to the areas of great interest which is generally high latitudes due to its ability to distribute winds. The overall wind variability seasonally lowers as one tend to the southern hemisphere which makes countries in South America, Africa and Australia to be at better position of exploiting wave energy more than other countries in the world.
2 Project Research This idea of transforming wave energy to other usable form of energy has not been realised today but it has been in practice for several years. Among the referred in the exploitation of the wave energy resources is the France’s Girard brothers who made the attempt in 1799. Though little is known on the capturing device, in the late 18th century, there was an attempt to make use of the device in capturing wave energy by lifting sea water so that the energy stored can be used in future date. In the year 1899, a distance of 100km in the south of New York a new idea come in on wave energy convertor device by the Ocean Grove apparatus. The idea was basically on an intake plate that when joined to the shafts having many pumps connected to it, raised water to a number of elevated tanks, made it possible to continuously use the potential energy that is held by the stored water.
This device operated in Oceanographic Museum of Monaco for ten years using wave energy to pump water to the aquarium. The aquarium apparatus was later destroyed by the force generated by the wave’s energy. French scientist Montgolfier is another person who developed “Complaint flap” system in the pilot plant for the first time that was installed in the black sea around 1917 though later it was dismantled. In the same 1970s, research was carried out in depth on cavity resonance devices by Iosho Masuda together with Japan Marine Science and technology center and by R. M Ricafranca in collaboration with RMR research and engineering Services in the Philippines. The two researchers worked separately with an aim of coming up with the first wave energy convertors that can be used for commercial purposes.
The converters they were researching on were later referred to as the oscillating wave columns (OWCs) since their operating principles was based on oscillation of the waters inside the column chambers that were linked with the outer water by an opening that was below the surface. Oscillation wave columns worked in such that when the water level raises, the surrounding air is compressed and released from the chamber hence making the turbine to rotate. The hydraulic fluid that was pumped helped in driving turbine that was connected to the generators that produced electricity. The device that was developed in 1980s was stalled after calculations of its cost effectiveness indicated that its operation costs appeared to be very high. Further investigation that has been done of recent to reexamine the device showed that its cost is ten times less than what was initially estimated.
United Kingdom (UK) was not left behind in the wave energy convertor invention and research. Christopher Cockerell from Southampton worked towards designing and development of wave energy converter system by using relative movement of plates that were connected to each other by hinged joint. The system of the device operates in such that when one pair of the sluice gate open up then the crest of the wave automatically hits the anchored structure which makes water reach the highest level where it is diverted by the turbine in the direction of the twin tank that are located at the sea level of the trough. After the passage of the crest, the second tank sluice gate opens collecting the water directed from the turbine hence making a complete cycle.
The wave energy converter that was developed in 1970s and 1980s did neither pass through experimentation processes nor did they produce a relevant quantity of energy, but as it has been explained in some sections of this paper, the investigations and the research made by various scientist during that period build the bases that are used in developing the devices that are used in the present to the various part of the world. Among the recent research, the Queens University that is found in Belfast in the year 1991 developed and tested a small device that was capable of producing power in the size of 75 kW aiming at gathering the important information and gain the necessary experience in the field of developing terrestrial oscillating wave converters (OWCs).
The University research resulted in putting into operation Land Installed Marine Pneumatic Energy Transmitter (LIMPET) in the year 2000 on the Islay Island of Scotland. The two types of convertors are; point absorbers and line observers. According to the existing theories, the capture system in the point absorbers lacks dominating dimensions in the beginning which makes it to be represented as a point on some nautical chart and further proceeds to the sea surface perpendicularly. A good example of the point absorbers is a buoy. Contrary to the point absorbers, line absorbers capture systems has a dominating dimension in the beginning that can either be transverse or longitudinal depending on the direction of the incoming wave. 4 Mode of Operation WaveRush applies the concept of oscillating water column in its operation though when converting wave energy into pneumatic energy it uses different means.
This offers a great potential in the context of the United Kingdom generation of the renewable energy by applying the concept used in the shoreline and nearshore. There are limited number of breakwater in existence but in the areas where they exist, WaveRush is used as means of converting breakwaters that is in existence or that is planned into wave energy. 6 Design of Wave energy convertor After the research, I have chosen a similar design with the OSCILLATING WATER COLUMN wave energy convertor. By using the pipes in diameter of 110mm, thickness of 2mm, form a path for the wave and air pressure to transfer to the outlet pipes with a narrowed down diameter of 50mm. At the end of the pipe, there’s a pressure gauge to measure the outlet pressure gained.
Point worthy noting is that if the effects of the compressible air are to be reproduced in the right manner without having linkages then the cumulative volume of the air divided by the area that is not covered by the water surface within the chamber, exactly the same values at both full scale and the model that is used in the experiment. Waves used in the experiment was generated by a piston, which is a kind of wave maker (shown in Figure. The heights of the waves were conducted by measuring wave gauges using an array of three conductive type. Among the gauges that were used, one of them was positioned on top of the middle tube used in the model while the remaining two wave gauges were positioned on top of the flume vertically, such that they were used in measuring wave that is being generated by the piston (wave maker).
The results obtained from the wave gauges was used for two purposes; to determine the incident and to reflect the height of wave component (Knott & Flower 1979). Record the peak and trough in the water tank, the voltage of the pressure gauge will automatically record in the Microsoft excel. Repeat the experiment by the same methods but using different amplitude values: 0. 020m, 0. 025m, 0. 030m, 0. Figure. 1 Wave maker in the flume Figure. 2 Prototype of the WEC lower part Figure. 3 Prototype of WEC upper part 4. 0 Observations and Results The results below are the Voltage against the Time with different frequency, amplitude, and water level. 75Hz Peak= 0. 597m Trough= 0. 584m Water level= 0. 60m Figure. 2 Graph of Voltage against Time with amplitude 0. 60m Figure. 4 Graph of Voltage against Time with amplitude 0.
030m Frequency= 0. 75Hz Peak= 0. 603m Trough= 0. 85Hz Peak= 0. 646m Trough= 0. 540m Water level= 0. 60m Figure. 7 Graph of Voltage against Time with amplitude 0. 60m Figure. 9 Graph of Voltage against Time with amplitude 0. 040m Frequency= 1. 15Hz Peak=0. 632m Trough= 0. 75Hz Peak= 0. 716m Trough= 0. 647m Water level= 0. 68m Figure. 12 Graph of Voltage against Time with amplitude 0. 10 to Figure. 12 is under the condition of same frequency and same amplitude but different water level. Water level of 0. 60m does not submerge whole inlet pipe, water level of 0. 64m submerge the whole inlet pipe, but during the experiment, there is air leaking out from the inlet pipe, because of the wave form. However, the height of the water tank in flume is set, if the water pressure is increased, the water will split on the floor.
0 Recommendations The exploration of the device requires to be improved in different areas, in order to make it available and affordable to the individual living in different part of the country that is providing it and also make other countries feel the important of developing such environmental friendly source of energy. For the purpose of increasing energy generated by the device, the middle pipe is supposed to be made short so that it can be able to provide pressure at high level through the outlet pipe. The water tank height is also supposed to be set in such that when the pressure is increased, water in the tank will not split on the floor. The water level in the tank should be increased in order to increase the pressure generated by the inlet pipes and prevent the pressure that is escaping from the inlet pipes.
Methodology of the construction has been examined and noted that it can be done in exposed areas in the coastal region. The method that is more economical in constructing the device is by using end tip of the rocks that are quarried locally. This method seems to be cost saving as compared to the design of caisson breakwater. 0 References Al-Habaibeh A. , Su D. Carbon Trust 2005, Arup, Eon, “Oscillating Water Column Wave Energy Converter Evaluation Report” Chaplin J. R. , Farley F. J. M. Page 237 – 251 Clément A. , McCullen P. , Falcão A. , Fiorentino A. , Gardner F. Springer. [Gives a future worldwide estimation of the wave energy resource]. Curran R. , Whittaker T. J. ETSU v/06/00183/00/rep 2003, Research into the further development of the limpet shoreline wave energy plant supplement to the final report.
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