ARSHAD BABU Mechanical Engineering student,TKM College of engineering,kollam,Kerala,India

1. OCEAN ENERGY CONVERSION
methods
Guided By:prof. JESNA MOHAMMED
Arshad babu. U
M7B Roll No: 7457
TKMCE kollam

2. INTRODUCTION
What is Ocean Thermal Energy Conversion?
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.
On an average day, 60 million square kilometers (23 million
square miles) of tropical seas absorb an amount of solar
radiation equal in heat content to about 250 billion barrels of
oil.
If less than one-tenth of one percent of this stored solar
energy could be converted into electric power, it would
supply more than 20 times the total amount of electricity
consumed in the United States on any given

4.  1881-Arsonval,a French scientist first to propose tapping the thermal
energy of the ocean
 1881-Georges Claude built an experimental open cycle OTEC system
System produced 22 kw electricity
 1956-French researchers designed a 3 megawatt open OTEC unit at
Africa's west coast .It was too expensive and they quit the project
 1979-The first 50 kw closed cycle OTEC demonstration plant went up
at Nelha known as “MINI OTEC”
 1980-US Department of energy built “OTEC-1”
 1981- japan demonstrated a shore based,100kw closed cycle plant
Freon was the working fluid and Titanium shell and tube exchanger
was used
 1984-Solar energy research institute developed a vertical evaporator to
convert warm sea water into low pressure steam for open cycle plants

5.  March 2013-Saga University with various Japanese industries
completed the installation of a new OTEC plantOkinawa Prefecture
announced the start of the OTEC operation testing at Kume Island
on April 15, 2013.

6. WORKING PRINCIPLE
Oceans layers of water have different temperatures to drive a power
producing cycle.As long as the temperature between the warm surface
water and the cold deep water differs by 20degree.Cel,an OTEC system can
produce significant amount of power.
ELECTRICITY PRODUCTION
 CLOSED CYCLE OTEC SYSTEMS
 OPEN CYCLE OTEC SYSTEM
 HYBRID OTEC SYSTEM

7. WORKING PRINCIPLE
Oceans layers of water have different temperatures to drive a power
producing cycle.As long as the temperature between the warm surface
water and the cold deep water differs by 20degree.Cel,an OTEC system can
produce significant amount of power.
ELECTRICITY PRODUCTION
 CLOSED CYCLE OTEC SYSTEMS
 OPEN CYCLE OTEC SYSTEM
 HYBRID OTEC SYSTEM

8. OPEN CYCLE OTEC SYSYTEM
This system relies on a low-pressure environment to actually boil the
ocean water and create steam. When warm ocean water moves into a
low-pressure environment it will boil. The steam is almost pure water as
the salts and other impurities are left behind. The steam then recirculates
and condenses back to water. The warm sea water is flash evaporated in
vacuum chamber at an absolute pressure of 2.4 kilopascals. Steam
expands over a low pressure turbine and the generator produces the
electricity

9. OPEN CYCLE OTEC
The open cycle plant needs very large size turbine because of large volume of
steam at low pressure approximately at .002 bar. The average pump work is
required in open cycle a the plant has to handle very large quantity of warm and
cold water because of low water temperature difference

10. CLOSED CYCLE OTEC
Warm sea water vaporizes a working fluid, such as ammonia,
flowing through a heat exchanger. The vapor expands at moderate
pressures and turns a turbine coupled to a generator that produces
electricity. The vapor is then condensed in another heat exchanger
using cold sea water pumped from the oceans depths through a cold
water pipe. The condensed working fluid is pumped back to the
evaporator to repeat the cycle. The working fluid remains in a
closed system and circulates continuously

11. CLOSED CYCLE OTEC

12. Advantages of Closed cycle OTEC
 The size of the plant is lowered in closed cycle compared with
open cycle because of high running pressure 9-16 bar.
 Cost of energy generation is reduced in closed cycle.
 Higher efficiency.
 Corrosion on turbine and other parts is avoided.
 As the secondary fluid boils at temperature available in hot water
and doesn’t require vacuum pump.
 Fabrication of steam turbine is easier than a large turbine used in
open cycle.

13. 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. The steam vaporizes the working fluid of
a closed-cycle loop on the other side of an ammonia vaporizer. The
vaporized fluid then drives a turbine that produces electricity. The steam
condenses within the heat exchanger and provides desalinated water

14. HYBRID OTEC SYSTEM

15. ADAVANTAGES
 It is environmentally friendly.
 It can provide useful environment in areas bordering on
tropical seas.
 It can produce electricity without giving off any CO2, and do it
for a long period.
 The additional products i.e., food, potable water; air
conditioning; etc. which can readily be provided.
 Potable water production alone can reduce electrical
generating costs by up to one third, and is itself in very
considerable demand in most areas where OTEC can
operate.
 The cold seawater is rich in nutrients and can be utilized for
water plants or for aquaculture used to increase the
production.
 The thermal resource of the ocean ensures that the power
source is available day or night, and with only modest
variation from summer to winter.

16. DISADVANTAGES
 The power cost is more.
 The construction and pipe length affects the marine
ecosystem.
 The closed cycle OTEC can cause the pollution, if
intermediate chemicals leak into the ocean.
 Heat exchangers (Evaporator & Condenser) must be made of
highly conductive materials, which increase their capital cost.

17. APPLICATIONS OF OTEC SYSTEM
 A closed cycle OTEC plant can also act as chemical
treatment plant.
 The enclosing area can be used for aquaculture and
maricultue.
 The deep sea coldwater is rich in nutrient and can be used
for various applications.
 Desalinated water, which can be used for irrigation and
human consumption

18.  The marine environment gets affected by these plants through
water heating.
 The release of toxic chemical and entrapment of small sea
organism in intake pipes is common.
 Thermal layer of seawater near the plants get disturbed
because of the discharge of low and high water at intermediate
level.
 The marine life gets affected because of change in pH and
dissolved Oxygen.

19. The periodic rise and fall of water level of sea which are carried by the
action of the sun and moon on water of the earth is called “tide”. The large
scale up and down movement of sea water represents an unlimited source of
energy.
The main feature of the tidal cycle is the difference in water surface
elevations at the high tide and at the low tide. If the differential head could
be utilized in operating a hydraulic turbine, the tidal energy could be
converted into electrical energy by means of an attached generator.
A Tidal power plant mainly consists of the following:
1. A barrage with gates and sluices
2. One or more basins
3. A power house

20. A barrage is a barrier constructed across the sea to create a basin for storing
water. The barrage has to withstand the pressure exerted by the water head
and also should resist the shock of the waves.
A basin is the area where water is retained by the barrage. Low head
reversible water turbine are installed in the barrage separating the sea from
the basin.-

22. ADVANTAGES
 It is inexhaustible source of energy
 No problem of pollution
 The cost of power generation is quite low
 High output can be obtained compared to solar or wind energy
DISADVANTAGES
 Capital cost is very high
 As the head is not constant, variable output is obtained
 As the head is low, large amount of water is necessary for the turbine
 It will not operate when the available head is less than 0.5m

23. WAVE ENERGY
 Wave power refers to the capture of (ocean) wave energy to do
useful work including electricity generation, desalination, and filling a
reservoir with water
 Wave Power is renewable energy and is a form of solar energy
transferred to water by the wind
 Upto 2 terawatts (1 terawatt = 1 trillion watts)
 Initial solar power level of 100 W/m2 is concentrated to an average
wave power level of 70 kW per meter of crest length
 This rises to 170 kW per meter of crest length during winter and to
more than 1MW per meter during storms.
Carry energy in the form of potential energy which is characterized by
height and wave length which define energy parameters
Energy extracted from the Ocean waves is called Wave Energy in the
form of, – Potential Energy (pressure fluctuations below free surface)
Kinetic Energy (energy from free surface)

24. OSCILLATING WATER COLUMN
These devices generate electricity from the wave driven rise and falloff
water in cylindricalshaft.The rising and falling water column drives air into
and out of the top of the shaft, powering an air driven turbine
FLOATS OR PITCHING DEVICES
These devices produces electricity from the bobbing or pitching of a
floating object. The object can be mounted to a floating raft or to a
device fixed on the ocean floor
FOCUSING DEVICES
These shoreline devices also called tapered channel systems, rely
on a shore mounted structure to channel and concentrate waves,
driving them into an elevated reservoir.

25. OSCILLATING WATER COLUMN

27.  Over head power lines are required to transport the power
 We can alter ocean surface currents
 Effects some of the marine organisms
 Effects on shipping and navigation
 For this reason ,warning lights and clearly marked channels to
ensure the safe navigation around converters are essential

30. COMPARATIVE TABLE OF DIFFERENT SEA ENERGY RESOURCES

31.  NON-CONVENTIONAL ENERGY RESOURCES by S.K.DUBEY
 Engineeringpapers.blogspot.com
 www.matlabcodes.com
 Electrical Power Research Institute, Ocean Energy pro- gram,
Assessment reports, 2004 – 2006 (http://oceanenergy.epri.com/)

32. Thank you