MAHIDA HIRENKUMAR RANJITSINH
Mechanical Engineering Department
68.18% of the Earth is covered by the Oceans
(361 million square kilometers) So they
represent a rather large storage reservoir of
the solar input.
These Oceans are constantly being heated by
Solar energy absorbed by oceans is =
(4000 x humanity annual consumption)
Less than 1 % of this energy would satisfy all
Estimated that if 0.1% of the renewable
energy available from within the ocean was
converted into electrical energy, it would
satisfy the present world demand more than
5 times over.
Ocean Thermal energy Conversion (OTEC)
Hydrological Cycle. (Evaporation by Solar
First attempt in 1880’s
Jacques D’Arsonval proposed the idea of
converting differences in water temperature
in to electric energy.
George Cloud installed first OTEC plant in
1930 in Cuba.
It had generated 22kw of electricity with low
pressure steam turbine, however it did not
produce a net power.
Thermodynamic Principle of “PRIME MOVER”.
It does not require any type of minerals/
materials to produce energy.
Surface (Warm) seawater is flash evaporated
in a vacuum chamber resulting low-pressure
steam drives turbine-generator.
Cold seawater condenses steam after it has
passed through the turbine & produces fresh
Because of the need in the open cycle to
harness the energy in low pressure steam,
extremely large turbine are required.
More deareators must be used to remove the
gases dissolved in the sea water unless one is
willing to accept large losses in efficiency
Warm (surface) seawater and Cold(deep)
seawater used to vaporize and condense a
working fluid , such as ammonia ,freon or
propen which drives a turbine-generator in a
closed loop producing kWh.
It requires very large size Heat Exchangers.
The operating pressure is much higher than
of the water, being roughly 10 bar at the
boiler, and their specific volumes are much
lower, being comparable to those of steam in
Hence much smaller and less costly turbines
The temperature difference in the boiler and
condenser must be kept as low as possible to
allow for maximum possible temperature
difference across the turbine, which also
contributes to the large surfaces of these
Plate type heat exchanger instead of shell and
Due to formulation of bio fouling, corrosion
referred to a fouling and will tend to inhibit
heat transfer through it.
This cycle is an attempt to combine the best
features and avoid the worst features of the
open and closed cycles.
Sea water is first flash evaporated to steam,
as in open cycle and heat in the resulting
steam is then transferred to ammonia as in
the conventional closed cycle.
Closed cycle to be most economical in cost
and to require least power.
Closed cycle is favoured for the future
development in expectation of higher
efficiency but does not yet have the
advantage of having been put in practice.
Due to the lack of experience that puts ocean
thermal difference development at a
disadvantage and leads to emphasis on wind
Japan plans to lead the way in actual
development like materials, fouling problems
The sources of temperature difference for
this system are endless.
The ocean currents are not going to stop any
Works 100% coal and oil free.
Only makes sense to implement.
Must use a liquid with a low boiling
Propane (under the right pressure)
Uses the warm surface water heated by the
Sun to boil the propane
Colder denser water at the bottom of the
basin to condense the propane
OTEC project cell established at IIT, Madras
and has completed the feasibility study for
establishments of a 1 MW OTEC plant in
Preliminary Oceanographic studies of both
the island have seen large lagoons on the
A hydrographic survey of the proposed site
was undertaken by National Hydrographic
Office, Dehradun. The preliminary
assessment of survey indicates the availability
of suitable conditions for establishment of
Tide is a periodic rise and fall of the water
level of sea which are carried by the action of
the sun and moon on the water of the earth.
It has been estimated that about a billion KW
of tidal power is dissipated by friction and
eddies alone. This is slightly less than the
economically exploitable power potential of
all the rivers of the world.
First attempt in the 11th century in Great
Britain and later in France and Spain.
The main feature of the tidal cycle is the
difference in the elevations at the high tide
and low tide.
During the power generation process the
power is generated at both the times i.e. high
tide and low tide.
The first tidal power plant was commissioned
by General De Gaulle at La Rance in 1966.
The average tidal range is 8.4 m and the
maximum is 13-5 m. Effective basin area 22
Square km and basin volume 184000000 m3.
It has used single basin and submerged
reversible propeller type turbine generators
that could generate power with the water
flowing in either direction through the Bulb
Installed capacity is 240 MW.
Maximum utilization of stored hydraulic
potential energy is 18%, which may be
increased to 24% in future by addition of 80
MW more generating capacity.
Presently 2 power plants are operating in the
world . (France & USSR)
The Proxigean Spring
Tide is a rare, unusually
•This very high tide occurs
when the moon is both
to the Earth (at its closest
perigee, called the
proxigee) and in the
New Moon phase (when the
Moon is between the Sun
and the Earth).
•The proxigean spring tide
occurs at most once every
•Neap tides are especially weak tides.
They occur when the gravitational forces
of the Moon and the Sun are perpendicular
to one another (with respect to the Earth).
Neap tides occur during quarter moons.
Tides are produced mainly by the
gravitational acceleration of the moon and
the sun on the water of solid earth and the
70% of the tide producing force is due to the
moon and 30% to the sun.
The power house
The dam or Barrage to form pool or Basin.
Sluice ways from the basins to the sea and
The Bulb Group turbines.
Rim Type Turbines.
The power generation from tides involves
flow between an artificially developed basin
and the sea.
However in order to have more or less
continuous generation, this basin scheme can
be elaborated by having two or more basins.
Following type of arrangements are possible.
(1) Single Basin Arrangement.
(2) Double Basin Arrangement.
Generate power only intermittently.
The generation of power can be achieved in a
single basin arrangement either as a
(1) Single Ebb(flow back of tide) Cycle system.
(2) Single Tide Cycle system
(3) Double cycle system.