GEOENERGY

GEOENERGY, Ocean Thermal Energy Conversion(OTEC)

GHINIA ANASTASIA MUHTAR

geoenergy

Energy in Technological knowledge and in

physics can be interpreted as the ability to

do work. Kinds of energy, chemical energy,

electrical energy, mechanical energy, thermal

energy, nuclear energy,etc

Geoenergy is called earth’s energy or source of

energy.

HISTORY

In 1881, Jacques Arsene d'Arsonval, a French

physicist was the first to propose suppress heat

energy from the oceans. Georges Claude, a

student of d'Arsonval's, build an open-cycle

OTEC experimental in Matanzas Bay, Cuba, in

1930.In 1979 the first closed-cycle OTEC pilot

plant up at NELHA. Known as "Mini-OTEC"

UNDERSTANDING

OTEC or ocean thermal energy conversion is a technology that converts solar radiation energy to electric power. OTEC systems use the natural thermal gradient of the fact that the layer of the ocean sea water have different temperatures.

Working principle of otec

PICTURE OF OTEC

Kinds of otec

Closed-cycle

The system uses a fluid with low boiling points, such as ammonia, to rotate a turbine to generate electricity. Warm surface seawater is pumped through a heat exchanger where the fluid is vaporized low-boiling point. Expanding vapor turns the turbo generator. Cold sea water-in-pumped through a second heat exchanger, steam condenses back into liquid, which then recycled through the system.

In 1979, Natural Energy Laboratory and several private sector partners developed the mini OTEC experiment, which achieved the first successful at-sea production of net electrical power of a closed cycle OTEC. Mini OTEC vessel was moored 1.5 miles (2.4 km) off the coast of Hawaii and generate enough clean electricity to light bulbs ship and run the computer and television..

Open-Cycle

This system uses the warm surface waters of tropical oceans' to make electricity. When warm seawater is placed in a container of low pressure, it boils. Expanding steam drives a low-pressure turbine attached to an electric generator. Steam, which has left the salts behind in the low-pressure container, is almost pure fresh water. It is condensed back into a liquid by exposure to cold temperatures than in sea-water.

In 1984, the Solar Energy Research Institute (now the National Renewable Energy Laboratory) developed a vertical-spout evaporator to convert warm seawater into low-pressure steam for open-cycle plants. Energy conversion efficiency as high as 97% is achieved.

Hybrid

This system combines features of both closed cycle and open cycle system. In the hybrid system, warm seawater enters a vacuum chamber in which flash evaporates into steam, similar to the open-cycle evaporation process. Vapor evaporating low boiling-point fluid (in a closed-cycle loop) that drives turbines to generate electricity.

Otec benefits

1. Helps produce fuels such as hydrogen, ammonia, and methanol

2. Produce electrical energy

3. Produce desalinated water for industrial, agricultural land, and housing

4. Provide air conditioning for buildings

5. Provides temperature cooling

6. Improve competitiveness and international trade

7. Increasing energy independence and energy security

8. Support the socio-political stability of the international

9. Has the potential to reduce greenhouse gas emissions produced from burning fossil fuels.

10. In small island countries, the benefits of OTEC include self-sufficiency, minimal environmental impact, and improved sanitation and nutrition which results from greater availability of desalinated water and mariculture products.

Otec shortages

OTEC’s shortages, namely :

1.If using ammonia as the evaporated material will make leaks and pose a potential hazard.

2. Efisiensi total is still lower by about 1% -3%.

3. Only there are several hundred land-based sites in the tropics where deep ocean water close enough to shore to make OTEC plants feasible.

4. costs are still expensive

THANK YOU FOR YOUR ATTENTION