OCEAN THERMAL ENERGY

CONVERTIONPRESENTED BY:

RAJYALAKSHMI.D.M.V.S NAGMANI.VIII/IV EEE III/IV EEE

WHAT IS OTEC ?The main objective of ocean thermal energy

or Ocean Thermal Energy Conversion (OTEC) is to turn the solar energy trapped by the ocean into useable energy

This kind of energy is found in tropical oceans where the water temperature differs from surface to deeper into the sea. On the ocean surface it can be at least 20°C hotter or cooler than the temperature at a deeper sea level.

Working Principle:OTEC generates electricity by using the

temperature difference of 20°C(36°F) or more than that exists between the warm tropical waters at the sun warmed surface, and cold water drawn from the depth of 1000 meters.

To convert this thermal gradient into electrical energy, the warm water can be used to heat and vaporize a liquid.

The working fluid develops pressure as it is caused to evaporate.

This expanding vapor runs through a turbine generator and is then condensed back into a liquid by cold water brought up from depth and the cycle is repeated.

So far, this concept of producing energy is still experimental, although it is at least a century old; created by the French engineer Jacques D'Arsonval in 1881.

What region is an OTEC plant most suitable to?

• OTEC plants are most suitable for islands around the tropical region of the east Pacific Ocean.

• This is because OTEC plants can provide both energy and pure water at the same time with a relatively low cost. It is also because the ocean in that region has greater temperature differences, which is about 24 oC.

Depending on the locationLand based plantShelf based plantFloating plant

http://en.wikipedia.org/wiki/File:OTEC_in_Hawaii.jpg

IMAGE

The Queensland coast is a possible location for OTEC

Depending on the cycle usedOpen cycleClosed cycleHybrid cycle

Closed Cycle OTEC:Closed Cycle OTEC employs a low-boiling-

point liquid like propane or ammonia as an intermediate fluid. The OTEC plant first pumps in the warm sea water and boils the intermediate fluid.

The first closed cycle OTEC was built by French Ministry of Colonies and the Centre National de la Recherche Scientifique in 1942

Open Cycle OTEC:Open cycle OTEC is very similar to the closed

cycle one.The only difference is that an open cycle

OTEC does not use intermediate fluidThe sea water is the fluid that pushes the

turbine.The warm sea water on the ocean surface is

turned into low-pressure vapor under a partly vacuumed environment.

Open Cycle OTEC:This low-pressure vapor can then push the

turbine. Later, the vapor will be cooled down and turned into desalinated water by the colder water deeper into the ocean.

Hybrid Cycle OTEC• Hybrid Cycle OTEC is a theoretical method of

maximizing the use of ocean thermal energy.

There are two concepts:The first one is to use a closed cycle OTEC to

generate electricity to create the necessary low-pressure environment for the open cycle OTEC.

The second concept is to integrate two open cycle OTEC (one is used to create the vacuumed environment) so that there will be twice the amount of the original desalinated water.

Other than electricity generation, what else can an OTEC plant be used for?

open cycle and hybrid cycle OTEC plants can also produce desalinated water, which can be used for irrigation and human consumption.

A closed cycle OTEC plant can also act as a chemical treatment plant.

What are the advantages of OTEC?

The variety of products and services are the major advantage of OTEC plants.

Ocean thermal is also relatively clean and will not produce more pollutants that contribute to global warming.

What are the disadvantages of OTEC?

Despite the advantages of temperature moderation, the OTEC plants can alter and maybe damage the surrounding ecosystem.

Also, pollution can be caused by closed cycle OTEC if intermediate chemicals leak into the ocean.

Conclusion:

In this case the OTEC plant is free to drift in ocean areas with a high temperature differences, the power being used to split sea water into liquid hydrogen and liquid oxygen.

The hydrogen In some cases where it is economic, the oxygen too, is offloaded to shuttle tankers which take the product to energy-hunger countries.

So, in time, the entire world can benefit from OTEC, not just tropical and sub-tropical ares.

THANK Q