Experimental Validation of Power Output and Efficiency for an Oscillating Water Column (OWC)

Yıl 2024, Sayı: 225, 54 - 72, 30.06.2024

Şafak Nur Ertürk Bozkurtoğlu

https://doi.org/10.54926/gdt.1405048

Öz

With the global energy demand escalating and concerns over the environmental impact of fossil fuels, there's a pressing need for cleaner, sustainable alternatives. This study highlights the potential contribution of wave energy to the power needs of coastal structures in the context of renewable energy. The research evaluates the power output and efficiency for an Oscillating Water Column (OWC) system that can be integrated into coastal structures to meet part of their power needs. Findings from both theoretical calculations and a 1:10 scale model experiment are presented. The mechanical power output and efficiency of the system for a full-scale prototype were calculated for deep water conditions with a wave height of 3m. The water surface oscillation inside the chamber is assumed to reflect the oscillation occurring outside the chamber. The maximum average mechanical power output for the full-scale prototype, corresponding to a wavelength of 22.5 m, was determined to be 64.8 kW, achieving a mechanical efficiency of 64.4%.
The overall efficiency of the system is calculated as 55% by assuming the generator efficiency to be 85%, resulting in an average power output of approximately 55 kW. A 1:10 scale model of the OWC system with a Wells turbine was constructed and tested in a tank for deep water conditions. Froude similarity and Keulegan-Carpenter similarity were used, ensuring a seamless transition from the model to the prototype. The OWC model was subjected to controlled heaving motion with a period of T=1.2 s. The power generated by the OWC model illuminated four integrated 3.4V LEDs on the Wells turbine, which were used to measure the power output produced. The power output of the model was measured to be a minimum of 0.12 W for a rotational speed of 107 rpm, which corresponds to a power output of 12 kW for the scaled-up prototype. This system has the potential for further enhancement by incorporating multiple OWCs into coastal structures exposed to wave action. Such development could facilitate meeting the power requirements of coastal structures, thereby contributing to the promotion of both renewable energy generation and a sustainable environment. Future research will focus on optimizing OWC chamber sizes for specific sites and refining the model to better capture water surface oscillation dynamics.
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Anahtar Kelimeler

Renewable Energy, Wave Energy, Oscillating Water Column, Sustainability

Teşekkür

The author acknowledges resources and support from Ata Nutku Ship Model Testing Laboratory at ITU Faculty of Naval Architecture and Ocean Engineering

Salınımlı Su Kolonu (OWC) için Güç Çıkışı ve Verimin Deneysel Olarak Doğrulanması

Öz

Küresel enerji talebinin artması ve fosil yakıtların çevresel etkilerine ilişkin endişeler nedeniyle daha temiz, sürdürülebilir alternatiflere acil ihtiyaç duyulmaktadır. Bu çalışma, yenilenebilir enerji bağlamında dalga enerjisinin kıyı yapılarının güç ihtiyaçlarına potansiyel katkısını vurgulamaktadır. Araştırma, kıyı yapılarına entegre edilebilecek, böyle bu yapıların güç ihtiyacının bir kısmını karşılayabilecek bir Salınımlı Su Kolonu (OWC) sistemi için güç çıkışı ve verimliliği değerlendirmektedir. Hem teorik hesaplamalardan hem de 1:10 ölçekli bir model deneyinden elde edilen bulgular sunulmuştur. Tam bir prototip için sistemin çıkış gücü ve verimliliği, 3 m dalga yüksekliğine sahip derin su koşulları için hesaplanmıştır. Hazne içindeki su yüzeyi salınımının hazne dışında meydana gelen salınımı yansıttığı varsayılmıştır. Tam ölçekli prototip için 22,5 m dalga boyuna karşılık gelen maksimum ortalama mekanik güç çıkışı 64,8 kW olarak belirlenmiş ve %64,4'lük bir mekanik verim elde edilmiştir. Wells türbinli OWC sisteminin 1:10 ölçekli bir modeli oluşturulmuş ve derin su koşulları için bir tankta test edilmiştir. Froude benzerliği ve Keulegan-Carpenter benzerliği kullanılarak modelden prototipe sorunsuz bir geçiş sağlanmıştır. OWC modeli, T=1.2 s periyotla kontrollü dalıp-çıkma hareketine tabi tutulmuştur. OWC modeli tarafından üretilen güç, Wells türbini üzerindeki entegre dört adet 3.4V LED'i aydınlatmış ve bu da üretilen güç çıkışını ölçmek için kullanılmıştır. Modelin güç çıkışı 107 rpm dönüş hızı için minimum 0,12 W olarak ölçülmüştür ve bu da ölçeklendirilmiş prototip için 12 kW'lık bir güç çıkışına karşılık gelmektedir. Bu sistem, dalga etkisine maruz kalan kıyı yapılarına birden fazla OWC'nin dahil edilmesiyle daha fazla geliştirilme potansiyeline sahiptir. Bu tür bir gelişme, kıyı yapılarının güç gereksinimlerinin karşılanmasını kolaylaştırabilir ve böylece hem yenilenebilir enerji üretiminin hem de sürdürülebilir bir çevrenin teşvik edilmesine katkıda bulunabilir. Gelecekteki araştırmalar, belirli sahalar için OWC hazne boyutlarını optimize etme ve su yüzeyi salınım dinamiklerini daha iyi yakalayacak şekilde modeli iyileştirmeye odaklanacaktır.

Anahtar Kelimeler

Yenilenebilir Enerji, Dalga Enerjisi, Salınımlı Su Kolonu, Sürdürülebilirlik

Kaynakça

• Amilibia, J. L., & Iturregi, A. (2010). Selection of the Electrical Generator for a Wave Energy Converter.Renewable Energy and Power Quality Journal, 1, 125–134. https://doi.org/10.24084/repqj08.255
• Brito-Melo, A., Gato, L. M. C., & Sarmento, A. J. N. A. (2002). Analysis of Wells turbine design parameters by numerical simulation of the OWC performance. Ocean Engineering, 29(12), 1463–1477. https://doi.org/10.1016/S0029-8018(01)00099-3
• Čarija, Z., Kranjčević, L., Banić, V., & Čavrak, M. (2012). Numerical analysis of wells turbine for wave power conversion. Engineering Review, 32(3), 141–146.
• Cruz, J. (2008). Ocean Wave Energy Current Status and Future Prepectives. In Springer Series in Green Energy and Technology. https://doi.org/10.2174/97816080528511060101
• Cui, Y., & Liu, Z. (2015). Effects of Solidity Ratio on Performance of OWC Impulse Turbine. Advances in Mechanical Engineering, 7(1), 1–10. https://doi.org/10.1155/2014/121373
• Dean R.G., & Dalrymple R.A. (1994). Water Wave Mechanics for Engineers and Scientists. World Scientific Publishing.
• Dey, S., Sreenivasulu, A., Veerendra, G. T. N., Rao, K. V., & Babu, P. S. S. A. (2022). Renewable energy present status and future potentials in India: An overview. Innovation and Green Development, 1(1), 100006. https://doi.org/10.1016/j.igd.2022.100006
• Drew, B., Plummer, A. R., & Sahinkaya, M. N. (2009). A review of wave energy converter technology. Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy, 223(8), 887–902. https://doi.org/10.1243/09576509JPE782
• Falcão, A. F. de O. (2010). Wave energy utilization: A review of the technologies. Renewable and Sustainable Energy Reviews, 14(3), 899–918. https://doi.org/10.1016/j.rser.2009.11.003
• Grecian, W., INGER, R., Attrill, M., Bearhop, S., Godley, B., Witt, M., & Votier, S. (2010). Potential impacts of wave-powered marine renewable energy installations on marine birds. Ibis, 152, 683–697. https://doi.org/10.1111/j.1474-919X.2010.01048.x
• Heller, V. (2012). Development of Wave Devices from Initial Conception to Commercial Demonstration. In Comprehensive Renewable Energy (pp. 79–110). Elsevier. https://doi.org/10.1016/B978-0-08-087872-0.00804-0
• Henriques, J. C. C., Portillo, J. C. C., Gato, L. M. C., Gomes, R. P. F., Ferreira, D. N., & Falcão, A. F. O. (2016). Design of oscillating-water-column wave energy converters with an application to self-powered sensor buoys. Energy, 112, 852–867. https://doi.org/10.1016/j.energy.2016.06.054 Hutchison, Z. L., Lieber, L., Miller, R. G., & Williamson, B. J. (2022). Environmental Impacts of Tidal and Wave Energy Converters. In Comprehensive Renewable Energy (pp. 258–290). Elsevier. https://doi.org/10.1016/B978-0-12-819727-1.00115-1
• Josset, C., & Clément, A. H. (2007). A time-domain numerical simulator for oscillating water column wave power plants. Renewable Energy, 32(8), 1379–1402. https://doi.org/10.1016/j.renene.2006.04.016
• Kelly, T., Dooley, T., Campbell, J., & Ringwood, J. V. (2013). Comparison of the experimental and numerical results of modelling a 32-oscillatingwater column (OWC), V-shaped floating wave energy converter. Energies, 6(8), 4045–4077. https://doi.org/10.3390/en6084045
• Kyoto Protocol to the United Nations Framework Convention on Climate Change. (2023). Audiovisual Library of International Law. https://legal.un.org/avl/ha/kpccc/kpccc.html
• Martins-Rivas, H., & Mei, C. C. (2009). Wave power extraction from an oscillating water column at the tip of a breakwater. Journal of Fluid Mechanics, 626, 395–414. https://doi.org/10.1017/S0022112009005990
• Minerals Management Service. (2006). Wave Energy Potential on the U.S. Outer Continental Shelf Introduction. Renewable Energy and Alternate Use Program, May. http://ocsenergy.anl.gov
• Mohamed, M. H. A. (2011). Design Optimization of Savonius and Wells Turbines [Otto-von-Guericke-Universit at Magdeburg]. In Faculty of Process and Systems Engineering: Vol. Doktoringe. https://www.mendeley.com/catalogue/design-optimization-savonius-wells-turbines/
• Okuhara, S., Takao, M., Takami, A., & Setoguchi, T. (2013). Wells Turbine for Wave Energy Conversion—Improvement of the Performance by Means of Impulse Turbine for Bi-Directional Flow. Open Journal of Fluid Dynamics, 03(02), 36–41. https://doi.org/10.4236/ojfd.2013.32A006
• Orphin, J., Nader, J.-R., & Penesis, I. (2022). Size matters: Scale effects of an OWC wave energy converter. Renewable Energy, 185, 111–122. https://doi.org/10.1016/j.renene.2021.11.121
• Patricio, S., Moura, A., & Simas, T. (2009). Wave energy and underwater noise: State of art and uncertainties. In OCEANS ’09 IEEE Bremen: Balancing Technology with Future Needs (p. 5). https://doi.org/10.1109/OCEANSE.2009.5278302
• PRIS - Reactor status reports—Permanent Shutdown—By Country. (2024, February 11). https://pris.iaea.org/PRIS/WorldStatistics/ShutdownReactorsByCountry.aspx
• Renewable Energy Fact Sheet: Wind Turbines. (2013). United States Environmental Protection Agency.
• Rodrigues, L. (2008). Wave power conversion systems for electrical energy production. Renewable Energy and Power Quality Journal, 1(06), 601–607. https://doi.org/10.24084/repqj06.380
• Rosati, M., Henriques, J. C. C., & Ringwood, J. V. (2022). Oscillating-water-column wave energy converters: A critical review of numerical modelling and control. Energy Conversion and Management: X, 16, 100322. https://doi.org/10.1016/j.ecmx.2022.100322
• Shehata, A. S., Xiao, Q., Saqr, K. M., & Alexander, D. (2017). Wells turbine for wave energy conversion: A review. International Journal of Energy Research. https://doi.org/10.1002/er.3583
• Shishlov, I., Morel, R., & Bellassen, V. (2016). Compliance of the Parties to the Kyoto Protocol in the first commitment period. Climate Policy, 16(6), 768–782. https://doi.org/10.1080/14693062.2016.1164658
• The Paris Agreement, UNFCCC. (2024, February 9). https://unfccc.int/process-and-meetings/the-paris-agreement
• University of South Florida, & Blackwood, M. (2016). Maximum Efficiency of a Wind Turbine. Undergraduate Journal of Mathematical Modeling: One + Two, 6(2). https://doi.org/10.5038/2326-3652.6.2.4865
• Zheng, S., Zhang, Y., & Iglesias, G. (2019). Coast/breakwater-integrated OWC: A theoretical model. Marine Structures, 66, 121–135. https://doi.org/10.1016/j.marstruc.2019.04.001