Ocean thermal energy convertion

Presentation

by

Rakib Hossain

ID: 11.02.08.047

What is ocean thermal energy conversion (OTEC) Temperature difference between cooler deep &

warmer surface to run a heat engine and produce electricity.

Distance between surface & cooler deep should be 1000m.

Mainly rankine cycle is used in the process .

Refrigerants used- ammonia or R-134a .

Ocean thermal energy conversion

Process of OTEC

Cycles in OTEC >>>

Open cycle

Close cycle

Hybrid cycle

Open cycleWarm surface water is used directly.

First surface water is pumped for boiling.

Produced steam drives to turbine connected to generator.

Steam is condensed by the cold temperature from deep water.

closed cycle

Closed cycle

•Uses fluid with low boiling point.•Surface water pumped by heat exchanger to vaporize fluid.•Fluid vapor turns the turbo generator.•Vapor condensed by the flow of cold water by 2nd heat exchanger.

Hybrid cycleCombination of closed & open cycle.

Evaporation is same as open cycle.

Working fluid vaporized as closed cycle.

Vaporized fluid drives turbine.

Working fluid

Popular choice – ammonia >> easy availability >> but toxic & flammable.

Fluorinated carbon – CFC or HCFC >> not toxic or flammable >> destroy ozone layer.

Hydrocarbons >> highly flammable .

Thermodynamic efficiency

Temperature difference between surface and deep water is high in tropic , helps to run heat engine.

It is 10 to 100 times more efficient than wave power of ocean.

It can supply continuous base load supply to power generation system.

It is considered as emerging technology.

Evolution of OTEC

1880 >> 1st attempt to develop OTEC . 1930 >> 1st OTEC plant built in Cuba . (22 kw) ,

destroyed by storm later . 1967 >> 1st use of closed cycle of rankine

system . Japan is the major contributor of OTEC since

1970. 2002 >> OTEC plant in tamilnadu , India. OTEC plant is increasing day by day .

Different types of OTEC sites

Land sites >>near sea shore Advantages >> do not need { sophisticated mooring,

long cable, extensive maintenance} Shelf based >>Far from surf zone, near to cold water.Disadvantages >> difficult product delivery, long cable

needed, more expensive. Floating sites >>Operate off shore, optimal for large system.Disadvantage >> complicates power delivery , possibility

of damage of cable, difficult to maintain & repair.

Related activities other than power generation Air conditioning

Chilled soil agriculture

Hydrogen production

Producing distilled water

Aqua culture

irrigation

Figure of related activities other than power generation

Cost & Economics It is a renewable energy .

One study shows that its cost is US $ 0.07 per kilowatt –hour.

Beneficial fact : lack of waste products and fuel consumption.

Supplemental use of sea water.

Many more useful fact other than power generation.

Environmental impact

Carbon dioxide dissolve

Unbalance ecological system

Accidental condition of closed cycle

Effect in commercial fishing

Conclusion

We need 6500 MW electricity per day , but we are producing only 5500 MW .As it’s a low cost harmless renewable energy to produce electricity , it could be bless for our country.

For more info please visit ;www.OTEC.org

Thank you all

Any question??