Post on 08-Dec-2015
description
Ocean Thermal Energy Conversion
Content
• Introduction
• Present Energy Resources
• Renewable Energy
• What is OTEC?
• Working Principe
• for besides produce electricity?
• Costs
• Projects
• Conclusion
Introduction
Energy is the raw material needed to fuel
any country’s economy growth. Advanced
economies have the capacity to develop
new sources of energy production or to
secure imports of foreign energy to meet
their needs.
Present EnergyResources
• Fossil fuels - coal, oil and natural gas.
• Nuclear fuels
• Difficult to estimate how long these fuels
will last - but is it sustainable
economically or environmentally?
Renewable Energy
Renewable Energy - Renewable energy is
natural energy which does not have a
limited supply. Renewable energy can be
used again and again, and will never run
out.
Sources of Renewable Energy
Renewable resources include solar energy,
falling water, wind, geothermal, waves and
temperature differences in the oceans
OTEC - Ocean Thermal Energy Conversion
The oceans cover a little more then 70
percent of the earth surface. This makes it
the world’s largest solar energy collector
and energy storage system.
1/10 of 1% of stored solar energy could
supply 20 times the amount of electricity
consumed in the USA on any given day
What is OTEC?
Ocean thermal energy conversion, or
OTEC, is a way to generate electricity using
the temperature difference of seawater at
different depths.
natural thermal gradient of the ocean
OTEC utilizes ∆ T
between warm
shallow and cold deep
ocean waters to run a
heat engine.
Global Ocean Thermal Gradient
WORKING PRINCIPLE
OTEC utilizes the ocean’s 20ºC natural
thermal gradient between the warm surface
water and the cold deep sea water(around
1 Km.) to drive a Rankine Cycle
Rankine cycle
How does OTEC work?
Cold Water Pipe Function:
• Bring up cold water
for OTEC cycle
• 4m diameter for the
10MW Pilot Plant
• 10m diameter for
100MW commercial
plant
• 1000m long
classification
Depending on the location
–Land based plant
–Floating plant
Depending on the cycle used
Open cycle
Closed cycle
Hybrid cycle
ELECTRICITY PRODUCTION
1. Closed cycle
• Ammonia can be used as a working fluid
2. Open cycle
• Water is the working fluid
• Desalinated water can be produced
3. Hybrid cycle
• Ammonia is the working fluid
• Warm sea water is flashed and is then used to vaporize ammonia
OTEC systems efficiency
• The OTEC systems efficiency is not quite
high because of the little temperature
difference used in the thermodynamic
cycles.
• Carnot Efficiency =𝑇1−𝑇2
𝑇1
SUMMARY
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 largest temperature differences.
3. Uses the vertical temperature gradient
in the ocean as a heat sink/source
What can you use OTEC for besides
produce electricity?
• Fresh Water
• Sea Food
• Air Conditioning
It is possible to use this resource to produce
fresh water instead of producing electric
power if there is a large ask for fresh water.
Fresh Water
The yield of fresh water from a 100-
megawatt power plant would be
approximately 33,000,000 cubic meter per
year, comparable to a flow of a medium-
sized river.
Sea Food
• OTEC plant it will stimulate the growth of
all kinds of seafood.
• The amount of food that can be produced
in this way is very large, larger in market
value than the electric power produced by
the plant.
Air conditioning and Refrigeration
Seawater air conditioning pumps cold
seawater (5oC) to a station via a deep-sea
pipeline to a cooling station, where it is
used to cool freshwater, which is then piped
to a building’s air conditioning system.
How much does an OTEC power plant cost?
The price of the first 10-megawatt plant is
$40,000,000; including development costs
and will produce profits of some
$10,000,000 per year, which means a
return of 25%.
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.
Mini OTEC (1979)
210 kW OC-OTEC Experimental Plant 1993
Conclusion:
• Though OTEC is clean and has great
potential, we have to make it more
efficient and cheap also.
• The main advantages of OTEC is that the
method is fuel free, can supply pure water
for both drinking and agriculture, can
supply refrigeration and cooling and can
provide a coastal community with reliable
energy.
Thank You