Dalga enerjisi dönüşüm sistemi tasarımı ve deneysel çalışması
A design and experimental study on wave power conversion system
Yazar: SELÇUK MERT
Danışman: PROF. DR. M. SEDAT KABDAŞLI
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Kıyı Bilimleri ve Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2012
Konu: Enerji = Energy ; İnşaat Mühendisliği = Civil Engineering
Dizin: Dalga denklemleri = Wave equations ; Enerji = Energy ; Yenilenebilir enerji kaynakları = Renewable energy resources

Özet:
Dünyanın enerji rezervleri gün geçtikçe tükenmeye yaklaşmaktadır. Bu doğrultuda enerji savaşları şiddetlenmekte, mevcut enerji yöntemleri ise zararlı etkilerini artırmaktadır. Fosil yakıtların tükenme eğilimine girmesiyle birlikte, enerji gereksiniminin karşılanmasında yeni arayışlar kaçınılmaz olarak ilerlemektedir. Nükleer enerji gibi alternatifler kullanım riskleri ve doğaya etkileri açısından bir takım problemler içermektedir. Yeni arayışlarda en iyi alternatif olarak rüzgar, dalga, güneş ışınları, hidrolik, biyomas ve jeotermal gibi yenilenebilir enerjiler ön plana çıkmaktadır. Yenilenebilir enerji kaynaklarından dalga enerjisi doğada yüksek potansiyelde var olmakla birlikte, günümüz şartlarında ekonomik değildir. Fakat, fosil kokenli yakıtların giderek tükenmesi, bu arada neden oldukları ağır çevre sorunları bu doğrultuda çalışmaların ilerlemesini zorunlu kılacak ve dalga enerjisi teknolojisindeki gelişmeler, dalga enerjisini de ekonomik hale getirecektir. Dünya üzerinde bir çok ülke dalga enerjisinden aktif olarak faydalanabilecekleri imkanlar ve yöntemler yaratmaya başlamışlardır.Dalga enerjisinden; cisim hareketini veya cisimdeki şekil değiştirmeyi kullanan sistemler, su basıncını kullanan sistemler ve hava basıncını kullanan sistemler olmak üzere temelde üç yöntemle elektrik enerjisi elde edilmektedir. Bu çalışmada; öncelikle dalga oluşumu, enerjisi ve dalga enerjisi tesisleri ile ilgili genel bilgiler aktarılacak, dünyanın ve Türkiye'nin bu teknolojide bulunduğu durum irdelenecektir. Devamında ise dalga enerjisini elektrik enerjisine çevirmek üzere tasarlanmış iki model üzerinde yapılmış deneysel çalışmalar ortaya konacaktır.Kullanılan sistemler temel olarak dalganın yarattığı düşey salınımları elektrik enerjisine çevirmeyi amaçlamaktadır. Buna göre iki sistem de silindirik plastik bir plakanın dalga etkisiyle düşey hareket yapması ve bu hareket enerjisinin elektrik enerjisine dönüşümü üzerine kuruludur. Birinci sistem elektrik üretimini dişlilere bağlanmış br dinamonun dairesel hareketiyle sağlarken, ikinci sistemde elektromanyetik bir sistem oluşturularak, bobin içerisinden geçen mıknatıslı çubuğun elektrik üretmesi denenmiştir.Deneyler sonucunda dişli sistemlerinin yük kayıplarını artırması neticesinde elektrik üretimi dikkate değer seviyeye ulaşamamıştır. İleriki çalışmalara örnek teşkil etmesi adına bu sistem de bu çalışmada detaylı olarak açıklanmıştır.Diğer sistemde ise elektrik üretimi sağlanmış ve verim değerleri tespit edilmiştir. Bu değerlerin elektrik üretiminin işlevsel olabilmesi adına artırımının sağlanması gerekmektedir. Bu doğrultuda yapılan deney, sistemde yapılacak olan zenginleştirmelerin ve malzeme seçimine dayalı bir takım düzenlemelerin sistemin gerçek üretim şartlarında sağlayacağı fayda hakkında fikir sahibi olunmasını sağlamıştır.

Abstract:
Energy reserves on earth are getting closer to end day by day. As a result, energy wars are rising and the harmful effects of the current energy sources are leading earth to the end. Decrease in fossil fuels, inevitably, results with new searchs for new energy sources to fulfill energy need of human on earth. Alternative ways, like nuclear power are having problems due to the risk it promises about storage and environmental effects.Wind, hydroelectric, solar, biomass and wave powers seem to be the best match for an alternative solution to meet the energy need of world. Wave power, as one of these solutions, is having a high potential to use , however it is not economic enough yet. Till, the decrease of fossil fuels and negative effects of traditional energy sources on earth, push scientist to make researches in this way. Thus, new technologies and developments result with cheaper and easier usage of wave power.Wave power is generated from waves by three main methods: Motion of substance, motion and pressure of wave and pressure of air. In this study, wave features, occurance of wave energy and wave energy plants will be investigated and the conditions of wave energy productions in Turkey and in the world will be addressed. Also calculation of wave power and conditions effecting wave energy will be mentioned.Besides, two different designs of wave energy conversion systems will be observed with experimental studies. Both systems are basicly designed to evaluate vertical oscilation motions of waves into the electrical energy. To make this happen, a horizontal plane was used in both systems and that plane oscilates during the wave motion. That vertical motion of the plane creates a motion energy and different systems in two experiments try to convert that mechanical energy into electrical energy.First system conveys the mechanical energy to a dynamo via disk systems. System was designed to turn dynamo in the same way while round plate is both moving up and down. That option is designed to avoid energy loss during change in direction of dynamo.Second system is designed on the basic electromagnetic system principles. Like the first convertion system a steel rod passes through round panel to make it move in a linear direction. Vertical movement of round plate also moves a magnetic stick into a coil to create electrical energy. The pipe, placed on the roun panel is filled with 10 magnets an those magnets produce energy with the movement in both up and down directions.For both systems the electrical energy emerged is produced as alternative current. In this study, also current types and electrical information to calculate the amount of energy produced are mentioned. To determine the way to observe electrical energy and the power also, magnetic properties of materials and principles of electromagnetism were addressed. Especially for the second system electromagnetic properties and relations effect the amount of energy and the power of electricity.Both tests were applied in test channels in Istanbul Technical University Civil Engineering Faculty Hydraulics Laboratories. The channel having 24 m length, 1 m. width and 1 m. depth was used for tests. For both tests water level in the channel was kept at 60 cm. high. Waves were produced by a wave generator system, from the beginning of the channel. Wave energy convertion systems were placed in the middle of the channel to avoid effects of reflecting waves.Volt and Amper values produced by system was written down via AVOmeter placed on coil. All the test process was recorded by video camera and to read the change in AVOmeter records were watched in slowed motion. After obtaining volt and amper values, the diagrams for current and voltage changes were observed. By using the maximum values on that diagrams energy values of observ ed from the waves are calculated and noted down.To obtain regular and consistent values and decrease the risk factor of labour phase differences between voltage and current flow are ignored for all six wave conditions. Thus both volt and amper values were assumed to be obtained and generated at the same time. Although that will increase the value for all waves, this also keep the difference at the same level and provide consistency while comparing wave conditions.At the end of tests no substantial energy production was observed from first type system. The reason for that was noticed as the energy loss caused by the disk systems. Also weigth of the material used for producing round plate caused that loss of energy. To give an opinion for further researches, details of that first type wave energy convertion system is being included in this study. Changes in disk systems or material properties can make system effective for energy convertion.For second type wave energy convertion system, six types of waves were used for determining energy production. Waves used in the experiment were choosen from waves having different wave height and different wave periods. Maximum wave height was 14,09 cm. and the minimum wave height was 10,19 cm. Besides maximum wave period was 1,40 sec. while minimum wave period was 0,81 sec.At the end of tests, maximum power is obtained as 0,110 Watt from the wave with 1,01 sec. wave period and 13,02 cm. wave height and minimum power obtained as 0,047 Watt from the wave with 0,81 sec. wave period and 10,35 wave height.The maximum efficiency was obtained from the wave with 10,19 cm wave height and 0,81 sec. period as 0,023. Also the wave from which the highest power obtained also worked with high efficiency comparing with others with the number of 0,016. The lowest efficiency value was obtained from the waves with the wave height of 11,33 cm. and 11,38 cm. respectively. The period values of these waves are same and 1,4 sec. for both.Comparing according to change in wave height, the highest current values are obtained as 15,15 mA from the waves with 14,09 cm wave height. The lowest current value is obtained as 9,83 mA from the wave with the height of 10,35 cm.Compared to change in the wave periods, the highest current values are obtained from the wave with the period of 1,21 sec. and the lowest current value is obtained from the wave with the period of 0,81 sec.Comparing according to change in wave steepness, the highest current value is obtained at the level 0,062 as wave steepness value and the lowest current valu is obtained at the wave steepness value of 0,10.Comparing according to change in wave height, the highest power produced is 0,11 watt and obtained from the wave with the height of 13,02 cm, besides the lowest power value is 0,047 watt which is obtained from the wave with the height of 10,35 cm.Comparing according to change in wave period, the highest power produced is obtained from the wave with the period of 1,01 sec. and the lowest power value is obtained from the wave with the period of 0,81 sec.Comparing according to change in wave steepness, the highest power produced is obtained from the wave with the steepness value of 0,082 and the lowest power value is obtained from the wave with steepness of 0,10.Those values showed that, optimum wave conditions are about having properties of 1 sec. Period time and about 13 cm wave height. These values also refer to wave steepness as 0,1 for optimum value. Changes in the mechanism of the system and material properties can give different results for wave dimensions.Regarding these values, it is possible to improve system properties and test conditions. Thus, considering large device farms can provide useful amount of energy production. These changes for second system seem to be preferably made on coil and magnet structure and amount in first sight. Also thickness, shape and the material type of round panel is important parameter for both systems.Test results show that, in case of proper wave conditions obtained and device properties for those waves designed these two systems can be evaluated into a preferable energy convertion systems.