Ocean thermal energy

OCEAN THERMAL ENERGY

ADELISA SENTIKA ANAK JUKA ANGEL KUOK MEI ERH

FATIN NABILA BINTI ISHAK HISHAM GEETHA BASHNI A/P SANDRISON

ENERGY

• Ability to do work• Anything that can be turned into

heat• Process of generating electricity from

heat

SOLAR ENERGY

• Harness light and heat from the sun• Active: solar collector uses photovoltaic panels to

convert sunlight• Passive: build houses from stone or clay• Advantages: free, pollution free, can be used in

rural area• Disadvantages: be harnessed during daytime and

sunny, solar panels are expensive, large areas required

GEOTHERMAL ENERGY

• Heat flows from hot interior of the earth• Volcanoes, hot springs and geysers• Produce hot water or steam which moves

through cracks in the rock• Advantages: pollution free, use small area• Disadvantages: difficult to maintain and repair

BIOMASS

• Waste materials being converted into energy• Waste wood, tree branches, garbage• Advantages: generate energy, always available• Disadvantages: expensive, inefficient when

compared to fossil fuels, require more land

OCEAN THERMAL ENERGY

• Thermal energy from Sun’s heat and mechanical energy from tides and waves

• Largest solar collectors (covers more than 70% of earth surface)

• Warms the surface but not into deep ocean water

• Temperature difference around 20 degree celcius can generate energy

• 1000m depth

• Relies on the relationship between pressure, temperature and volume• When there is difference in

temperature, it can be used to create an increase in pressure which will be used to drive turbine

Ocean Thermal Energy Conversion (OTEC)

• Three types of OTEC cycles–Close cycle–Open cycle–Hybrid cycle

Close cycle

• Organic Rankine cycle (ORC)– Operates on principles of evaporation and

condensation of working fluid– Organic fluid, eg. Ammonia circulates in a closed

loop of the system– It is more volatile, able to evaporate easily to

saturated vapour, less cost and easier to be transported

ORGANIC RANKINE CYCLE (CLOSE CYCLE)

(AMMONIA)

The turbogenerator then generates electricity and mechanical power

Latent heat is released from the ammonia vapor to cold sea water from condenser

Pressure of ammonia is increased

Kalina Cycle

• Another close cycle is Kalina cycle• Has better performance• Working fluid : ammonia-water mixture• Condensation and evaporation are allowed to

occur over a range of temperatures at a given pressure

• Less irreversibilities thus higher efficiency• A separator and a absorber are installed

Separates strong ammoina vapour from the weak solution

Absorbs the strong ammonia vapour onto the weak solution

Open cycle

• Claude’s cycle• Warm sea water as working fluid• Low pressure of 1% to 3% of atmospheric

pressure (Masutani & Takahashi, 2001)• Byproduct produced is the desalinated water

discharged as condensate• Desalinated water can be reprocessed into

potable drinking water

Flash evaporation of

warm sea water in a partial

vacuum

Expansion of the steam through a turbine to generate

power

Condensation of vapour by direct heat transfer to cold sea water

Compression and discharge of

condensate and any residual

noncondensable gas

CLAUDE’S CYCLE

Hybrid cycle

• Combination of 2 cycles: – Close cycle– Open cycle

• First cycle : Close cycle to produce electricity• Second cycle: Open cycle to produce

desalinated water• Uses ammonia as working fluid• Higher efficiency due to this combination

Hybrid Cycle

Potential of Ocean Thermal Energy

Conversion (OTEC) in Malaysia

Requirements??

- Δ T of at least 20 – 22 degree Celsius

- Surface T: 25 - 30 degree Celsius

-Deep sea T: 3 degree Celsius

- Depth of more than 1000 m

OTEC resources around the world…

Do you think the waters of Malaysia fit that requirement??

Studies done:Pulau Jambongan (northern coast of Sabah)

Kota Belud

Sibu

Straits of Melacca

Sabah Trough

Straits of Malacca…

- It one of the most longest Straits with constant flow

- Average depth : 40 m

- Shallow for OTEC system

- Potential area for tidal energy instead

Sabah Trough…

- Studies done by UTM-OTEC

- Depth: 2900 m

- Surface T: 29 degree Celsius

- Deep sea T: 3 degree Celsius

- Up to 50 000 MW

BENEFITS AND LIMITATIONS

BENEFITS

Pollution Control

Byproducts can be recycled

REFRIGERATION

AGRICULTURE

MARICULTURE

AQUACULTURE

ELECTRICITY

LIMITATIONS

LOCATION

Location : Sea

Location : Land

THANK YOU