Ocean Thermal Energy

1. Presentation on
Ocean Thermal Energy

2.  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.  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.  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.  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.  Heat Exchanger
 Turbine
 Seawater pump
 Cold water conduit
 Platform
 Data acquisition&
control

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

9.  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.  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.  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.  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.  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
Warm water flow rate 2100 kg/s
Cold water flow rate 1490 kg/s
Working fluid flow rate (ammonia) 31.6 kg/s

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.

16.  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.  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.  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.  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/