ocen thermal
TRANSCRIPT
-
7/28/2019 Ocen Thermal
1/17
History
1881: Jacques Arsene d'Arsonval, a French physicist, was the first topropose tapping the thermal energy of the ocean. Georges Claude, a
student of d'Arsonval's, built an experimental open-cycle OTECsystem at Matanzas Bay, Cuba, in 1930. The system produced 22kilowatts (kW) of electricity by using a low-pressure turbine. In 1935,
Claude constructed another open-cycle plant, this time aboard a10,000-ton cargo vessel moored off the coast of Brazil. But both plantswere destroyed by weather and waves, and Claude never achieved hisgoal of producing net power (the remainder after subtracting power
needed to run the system) from an open-cycle OTEC system.
1956: French researchers designed a 3-megawatt (electric) (MWe)open-cycle plant for Abidjan on Africa's west coast. But the plant wasnever completed because of competition with inexpensivehydroelectric power.
-
7/28/2019 Ocen Thermal
2/17
History- Contd
1979: The first 50-kilowatt
(kWe) closed-cycle OTECdemonstration plant went up
at NELHA.
Known as Mini-OTEC the plant wasmounted on a converted U.S. Navy
barge moored approximately 2 kilometers
off Keahole Point. The plant used a cold-water
pipe to produce 52 kWe of gross power and
15 kWe net power.
-
7/28/2019 Ocen Thermal
3/17
Ocean Power
Presented By-Rajesh Kumar RoyB.Tech 1st year
-
7/28/2019 Ocen Thermal
4/17
OTECOcean Thermal EnergyConversion
The technology that convertssolar radiation into electric power.
-
7/28/2019 Ocen Thermal
5/17
In detail - OTEC
Hydro energy conversion system
which uses sea's natural thermal
gradientthe fact that the
ocean's layers of water have
different temperatures
to run aheat engine.
-
7/28/2019 Ocen Thermal
6/17
In detail-1. Based on Rankine cycle - Thermodynamic cycle
which converts heat into work through a heat
engine
2. As with any heat engine , the greatest efficiency
and power is produced with the largesttemperature differences.
3. Uses the vertical temperature gradient in the
ocean as a heat sink/source
4. Temperature differences generally increases withdecreasing latitude , in the tropics, thereby mainly
used in
equatorial waters where temperature difference is
greatest
-
7/28/2019 Ocen Thermal
7/17
Process-
Carnot Efficiency (T1-T2)/T1:
in transferring heat to do work,
the greater the spread in
temperature between theheat source and the heat sink,
the greater the efficiency
of the energy conversion
T1- Temp at surface level
T2- Temp at bottom level
As long as the temperature between the warm surface waterand the cold deep water differs by about 20C (36F), an OTECsystem can produce a significant amount of power with amaximum Carnot Efficiency of about 6.7%
-
7/28/2019 Ocen Thermal
8/17
Open-cycle low-pressure OTEC uses the tropicaloceans' warm surface water to make electricity.When warm seawater is placed in a container, itboils. The expanding steam drives a low-pressure
turbine attached to an electrical generator. Thesteam, which has left its salt behind in the low-pressure container, is almost pure fresh water. It iscondensed back into a liquid by exposure to coldtemperatures from deep-ocean water.
-
7/28/2019 Ocen Thermal
9/17
-
7/28/2019 Ocen Thermal
10/17
Closed-cycle systems ( Rankine ) use fluid with a low-boiling
point, such as ammonia, to rotate a turbine to generateelectricity. Here's how it works. Warm surface seawater ispumped through a heat exchanger where the low-boiling-pointfluid is vaporized. The expanding vapor turns the turbo-generator. Then, cold, deep seawaterpumped through asecond heat exchangercondenses the vapor back into a
liquid, which is then recycled through the system.
-
7/28/2019 Ocen Thermal
11/17
Hybrid systems-
Hybrid systems combine the features ofboth the closed-cycle and open-cycle
systems. In a hybrid system, warmseawater enters a vacuum chamber whereit is flash-evaporated into steam, similar tothe open-cycle evaporation process. The
steam vaporizes a low-boiling-point fluid(in a closed-cycle loop) that drives aturbine to produces electricity.
-
7/28/2019 Ocen Thermal
12/17
-
7/28/2019 Ocen Thermal
13/17
Floating Plant for OTEC
-
7/28/2019 Ocen Thermal
14/17
Advantages-
Eco- friendly
Minimum maintenance costs compared to other powerproduction plants
Provide air conditioning to buildings within theOTEC
plant
Fresh water - first by-product is fresh water. A small 1 MW
OTEC is capable of producing some 4,500 cubic meters offresh water per day, enough to supply a population of 20,000with fresh water
Open cycleOTEC
systems can produce desalinated waterwhich is very important in third-world countries
Chilled soil agriculture- cold seawater flowing throughunderground pipes, chills the surrounding soil. Therebyallowing many plants evolved in temperate to be grown insubtropics due to temp. difference in the plant roots in cool soil
and plant leaves in warm air
-
7/28/2019 Ocen Thermal
15/17
Advantages- Continued
Mineral ExtractionOTEC helps in miningocean water for 57 trace elements. Most economic
analyses have suggested that mining the ocean for traceelements would be unprofitable as so much energy is
required to pump the large volume of water needed and
because of the expense involved in separating the
minerals from seawater. But in OTEC plants alreadypumping the water, the only remaining economic
challenge is to minimize the cost of the extraction
process.
-
7/28/2019 Ocen Thermal
16/17
Future
The economic evaluation ofOTEC plantsindicates that their commercial future lies infloating plants of approximately 100 MWcapacity for industrialized nations and smallerplants for small-island-developing-states
Small OTEC plants can be sized to producefrom 1 MW to 10 MW of electricity, and at least1700 m 3 to 3500 m3 of desalinated water per
day.
-
7/28/2019 Ocen Thermal
17/17
Thank you
Thank you Thank you
Thank you