Ocean Thermal Energy.pptx

Ocean Thermal Energy

1. Presentation on Ocean Thermal Energy

2. Content Introduction of OTEC Working Principle of OTEC Components of OTEC Plant Achievements In OTEC OTEC Cycle and System Open Cycle Close Cycle Advantage of OTEC Disadvantage of OTEC Indian Efforts on OTEC References

3. Introduction to OTEC There are different forms of Ocean energy :waves, tidal, marine currents and the thermal gradients Ocean thermal energy is created by solar energy –when ocean water absorbs solar radiation, the absorption of solar radiation causes a moderate temperature gradient to develop in water from the top surface to the bottom of ocean. The oceans cover a little more than 70 percent of the Earth's surface, this makes them the world's largest solar energy collector and energy storage system.

4. Achievements In OTEC In 1870, Jules Verne introduced the concept of OTEC In his novel Twenty thousand leagues under the sea. But Jacques d'Arsonval and his students Georges Claude were the pioneers of the OTEC. Claude built the first onshore plant in 1930 (in Matanzas, Cuba). The First Successful plant producing net power was Mini OTEC in Hawaii on 1979 . Subsequently several studies around the world have been conducted for the various complexities involved .

5. Achievements to OTEC Saga University in Japan has been working on the thermal cycles optimization in the laboratory for several years. Similarly US, Department of Energy has been funding activities on OTEC R&D with industry. Some plants which have been installed are Reunion Island Francs : 15 KW (2012) Kumejma Japan Saga University and Xenesys 100 KW(2013) Hawaii USA Makai Ocean Engineering 105 KW (2015) India has made attempted in 2000 to set up a 1MW Floating barge mounted plant off shore.

6. Components of an OTEC System Heat Exchanger Turbine Seawater pump Cold water conduit Platform Data acquisition& control

7. Components of an OTEC System Heat Exchangers are of shell and tube or plate type. Plate heat exchanger are more suitable for this application, since they are more compact than shell and tube exchangers The exchanger has sea water one side and the working fluid in the other. Hence the plate material needs to be compatible with sea water as well as working fluid for ammonia and sea water.

8. Closed-Cycle OTEC System In the closed-cycle OTEC system, warm seawater vaporizes a working fluid, such as ammonia, flowing through a heat exchanger (evaporator).

9. Open-Cycle OTEC System In an open-cycle OTEC system, warm seawater is the working fluid. The warm seawater is "flash"-evaporated in a vacuum chamber to produce steam at an absolute pressure of about 2.4 kilopascals ( kPa ).

10. Hybrid OTEC System A hybrid cycle combines the features of both the closed-cycle and open-cycle systems. In a hybrid OTEC system, warm seawater enters a vacuum chamber where it is flash-evaporated into steam, which is similar to the open-cycle evaporation process .

11. Advantages of OTEC OTEC plant can supply steady power without any fluctuation in all the weather conditions. Power output does not change from season to season . Useful by-products from OTEC plant are desalinated water and nutrients from marine culture. OTEC plant can be constructed on shoreline or on floating platform. The plant of any size or capacity can be constructed at suitable site.

12. Disadvantages of OTEC . OTEC plant has a very low efficiency in converting ocean thermal energy. A large plant size at huge cost has to be constructed to meet the power requirement. The design ,operation and maintenance of flash evaporator in the open system. The plant has to withstand severe ocean conditions and storms. The plant equipment has to resist the corrosive effects of ocean water .

13. Indian Efforts on OTEC In the year 1998 ,The National institute of Ocean Technology (NIOT) under the ministry of earth science embarked on the effects towards setting up to 1 MW floating plant in 1000 meter water depth about 40 Km from coastal city of Tuticorin in South India The Base line design conditions. Gross power rating 1MW Temp of warm water 29 °C Temp of cold water 7 °C W arm water flow rate 2100 kg/s Cold water flow rate 1490 kg/s Working fluid flow rate (ammonia) 31.6 kg/s  

14. View of the Barge mounted Desalination Plant

15. As the part of the commissioning activities ,various subsystem qualification tests were carried out on the shore as well as in shallow waters The OTEC barge sagar shakthi was berthed near the port and many subsystem were carried out. 1000 meter long pipe of 1 meter diameter was towed 40 km to the desired site. View of the Barge mounted Desalination Plant

16. View of the Barge mounted Desalination Plant India has the distinction of setting up a low temp. thermal desalination plant in kavaratti ,Lakshadweep for the first time ever in 2005 The plant is running successfully using thermal gradient in the ocean even toady generating 100,000 Liters per day

17. View of the Barge mounted Desalination Plant Subsequently Two more plants have been set up in island of Agatti and Minicoy. A barge mounted plant of capacity 1 million liters per day was also demonstrated offshore on the same barge built for OTEC.

18. Applications Ocean thermal energy conversion (OTEC) systems have many applications or uses. OTEC can be used to generate electricity, desalinate water, support deep-water Mari culture, and provide refrigeration and air-conditioning as well as aid in crop growth and mineral extraction.

19. References www.google.com https://www.niot.res.in Penney TR and Bharathan D (1987) Power from the sea. ScientiTc American 256(1) https://www.moes.gov.in https://www.eai.in https://www.indiascienceandtechnology.gov.in/ https://www.mheducation.co.in/

20. Thanks