A Study on Power from Ocean waves

 

Sundaresan.R1, Sasikumar.C2, Nagaraja. M3*, S.Karthikeyan3, MS.Sivahari Shankar3

1College of Applied Industrial Technology, Jazan University, Baish, Saudi Arabia.

2Department of Mechanical, Bannari Amman Institute of Technology (BIT), Sathyamangalam-638401.

3Department of Mechanical, PSNA College of Engineering and Technology, Dindigul-624622.

*Corresponding Author E-mail: madurainagaraja@gmail.com

 

ABSTRACT:

The non-renewable energy resources of petroleum and other CO2 sources are increasing the pollution level and causing the environmental effects. Future scenario coal and oil might not be a source of fuel for power generation. Solar energy contributes to a reduction of greenhouse gas emissions in comparison to energy generated from fossil fuels. It promotes viable source of energy, being renewable to meet global needs of power. The objective of present work is to investigate the feasibility of generating power indirectly from oceans by harnessing the temperature difference between the sun-warmed surface of tropical oceans and the colder deep waters.

 

KEYWORDS: Energy from ocean.

 


1. INTRODUCTION:

A significant fraction of solar radiation incident on the ocean is retained by seawater in tropical regions, resulting in average year-round surface temperatures of about 283ºC [1]. A 1 MW closed cycle OTEC demonstration system with a 4-stage axial flow reaction turbine was built in the year 2001 and pioneered by National Institute of Ocean technology (NIOT), Chennai. Compact plate type heat exchangers had been used for both evaporator and condenser side. The working fluid in the system is Ammonia [2]. Kalina an American physicist invented a new heat cycle, known as Kalina cycle, for thermal energy conversion using ammonia or water mixture as working fluid. OTEC is getting importance after the Fukushima nuclear accident in Japan. Faming Sun et al. (2011) reported that the potential of ocean energy is about a million kilowatt-hours per year [3]. Jacques Arsene d Arsonval et.al (1881) proposed tapping the thermal energy of the ocean. Georges Claude.,et.al (1930) built a 22kw OTEC plant with a low-pressure turbine. Also Claude. et.al (1935) built a 10,000-ton cargo vessel moored off the coast of Brazil which was destroyed by waves. In 1956, French scientists designed another 3 MW OTEC plant for Abidjan, Ivory Coast, West Africa. In 1964, J. H. Anderson developed a new closed cycle OTEC plant, which overcomes the weak point of Claude's system. An experimental set up of 50kw OTEC system was built at Keahole Point, Hawaii in May 1983. A vertical-spout evaporator to convert warm seawater into low-pressure steam for open-cycle plants was developed in 1984 by the Solar Energy Research Institute. The Energy conversion efficiencies in the system were reported to be 97%. In 1984 Dr. H. Uehara a Japanese physicist invented more advanced cycle for OTEC system. In 1985 Dr.Alex. Experts suggests it to be one of the most effective thermal conversion way in low temperature applications, which uses an organic fluid as a working medium and offers advantages over conventional rankine cycle with water as the working medium. Literature reviews showed that the temperature of the water in Deep Ocean is about 20°C (36°F). This is an ample heat source to convert the low boiling point fluids like propylene and ammonia to a gas or vapor. This temperature difference is also preferred to be sufficient to operate vapor turbines, which drive generators and produces electricity and fresh water as a byproduct.

 

 

2. OPERATION:

The principle of operation of an OTEC power plant is as similar to cyclic heat engines. An OTEC plant receives thermal energy through heat transfer from surface sea water warmed by the sun, and transforms a portion of this energy to electrical power. The Second Law of Thermodynamics precludes the complete conversion of thermal energy in to electricity. A portion of the heat extracted from the warm sea water must be rejected to a colder thermal sink. The thermal sink employed by OTEC systems is sea water drawn from the ocean depths by means of a submerged pipeline. A steady-state control volume energy analysis yields the result that net electrical power produced by the engine must equal the difference between the rates of heat transfer from the warm surface water and to the cold deep water [5].

 

Figure 1. Schematic diagram of a closed-cycle OTEC system. Faming Sun et.al (2011) [3]

 

3. SOLAR BOOSTED OTEC SYSTEM:

A solar-boosted OTEC system was proposed and first-order performance simulation was carried out in a 100kw OTEC system at Kumejima Island in southern part of Japan. Noboru Yamada et.al [6] envisaged that the installation of a solar collector with an OTEC system (Figure.3) enhanced the thermal efficiency of an OTEC plant. The thermal efficiency of SOTEC operation with 20-K solar boost is reported to be 2.7 times higher than that of OTEC operation. He reported that the utilization of a single-glazed flat-plate solar collector of 5000 m2 effective area boosted the temperature of warm sea water by 20 K.

 

Figure.3. Solar boosted Ocean Thermal Energy Conversion

 

4. CONCLUSIONS:

The feasibility of extracting energy from the Earth's oceans is envisaged. OTEC technology makes it possible to extract the energy from the suns radiation. Research experts suggest that OTEC plants can be sized to produce from 1 MW to 10 MW of electricity. The area suitable for OTEC ranges around the world from the tropics to semi-tropics. OTEC can be sited anywhere across about 60 million km2 of tropical oceans-anywhere there is deep cold water lying under warm surface water. Surface water regions, warmed by the sun, generally stays at 25°C or above. Ocean more than 1,000m below the surface is generally at about 4˚C. Further innovation research methods are is required in renewable ocean projects as the environmental effects and economic feasibility is shown to exists in most experimental outcomes. OTEC researchers report the unwillingness of private power sectors to make the enormous initial investment. So government’s initiation and financial incentives will attract and draws attention towards the technology. It was also suggested that careful site selection will not cause much impact to environment. OTEC technology has significant potential to provide energy free of greenhouse gas emissions in a cleaner way for the future. OTEC has the potential to produce fuels such as hydrogen, ammonia, and methanol.

 

5. ACKNOWLEDGEMENTS:

The authors acknowledge the guidance of co authors and also render sincere thanks to the reviewers of International Journal of Technologys for their constructive comments. Also the authors render their sincere thanks to Dr.K.Sivakumar, (Dean ) of BIT sathyamangalam for their motivation and support. Dr.Nagaraja M , highly expresses his gratitude to  Dr.Sundaresan .R  Former Sr.Professor of  VIT University for successful completion of the research work.

 

6. References:

1.      http://peswiki.com/index.php/Directory:Sea_Solar_Power

2.      http://www.esru.strath.ac.uk/EandE/Web_sites/02-03/ocean_thermal_energy /group% 20project/exports/otecex.html

3.      Faming Sun, Yasuyuki Ikegami, Baoju Jia, Hirofumi Arima., 2012. Optimization design and Exergy analysis of organic rankine cycle in ocean thermal energy conversion. Applied Ocean Research.35, 38– 46.

4.      Gerard C. Nihous, An estimate of Atlantic Ocean thermal energy conversion (OTEC) resources, Ocean Engineering 34 2210–2221 (2007).

5.      S. M. Masutani and P. K. Takahashi, Ocean thermal energy conversion, University of Hawaii at Manoa, Honolulu, HI, USA, 2001 Academic Press.

6.      Noboru  Yamada, Akira Hoshi, Yasuyuki Ikegami, Performance simulation of solar- boosted ocean thermal energy conversion plant, Renewable Energy 34 (2009) 1752– 1758.

 

 

 

Received on 19.02.2020            Accepted on 11.03.2020     

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Int. J. Tech. 2020; 10(1):21-23.

DOI: 10.5958/2231-3915.2020.00004.8