OCEAN THERMAL ENERGY CONVERSION

INTRODUCTION

• A source of renewable energy, uses the heat energy stored in the earth’s oceans to generate electricity.

• Works best when the temperature difference between warmer and the colder water is 36 deg F

• Exists in tropical coastal areas roughly between the tropic of Capricorn and the tropic of cancer.

NARRATION• OTEC was first proposed in the

year 1881 by Jacques Arsene d’Arsonval a French physicist.

• The US became involved in OTEC research in 1974 with the establishment of the Natural Energy Laboratory of Hawaii Authority.

OTEC TECHNOLOGIES

• Use fluid with low boiling point such as ammonia (33 degree C) to generate electricity.

• Warm sea water is pumped through heat exchanger to vaporize the fluid.

• Expanding vapour turns the turbo generator .• Cold water, pumped through a second heat exchanger,

condenses the vapour into a liquid and recycle through the system.

Closed cycle

OTEC TECHNOLOGIES

• Uses warm sea water directly to make electricity.• The water is first pumped into a low pressure container,

which causes it to boil. • The pure fresh water steam is further condensed by

exposure to cold ocean water.

• It combines the features of both above Said technologies.

Open Cycle

Hybrid Cycle

CURRENTLY OPERATING OTEC PLANTS

• In March 2013, Saga University with various Japanese industries completed the installation of a new OTEC plant.

• Okinawa prefecture announced the start of the OTEC operation testing at KUME Island on April 15,2013.

• In July 2014 DCNS groups partnered with energy announced NER 300 funding for their NEMO project.

ENVIRONMENTAL IMPACT

HYDRO DYNAMIC MODELING WORK In 2010 a computer model was developed to

stimulate the physical oceanographic effects of one or several 100 MW OTEC.

The model suggest that OTEC plants can be configured such that the plant can conduct continuous operation with variations of temperatures and nutrients within natural levels.

BIOLOGICAL MODELING WORKThe discharged nutrients could potentially

increase biological activity when accumulated in large quantities in the photic zones.

A biological component was added to the hydrodynamic computer model to stimulate the biological response to plumes from 100 MW OTEC plants.

ENVIRONMENTAL IMPACT

DISSOLVED GASSESThe direct contact condensers offer significant

disadvantages:• As cold water rises in the intake pipe, the pressure

decreases to the point where gas begins to evolve. • The direct contact heat exchanges may be justified

if a significant amount of gas comes out of solution.

TECHNICAL DIFFICULTIES

SEALING:-• The evaporator, turbine and condenser must be

carefully sealed to prevent in- leakage of atmospheric air that can degrade operation.

PARASITIC POWER CONSUMPTION BY EXHAUST COMPRESSURE:-

• A counter current region increases the gas steam reaction over which the non condensable gas steam is passed through after condensation.

• Result is 80% reduction in exhaust pumping power requirements.

TECHNICAL DIFFICULTIES

ADVANTAGES•Totally Renewable.•Generates electricity with no green house effect.•Produces desalinated water.

DISADVANTAGES•Needs a large difference in temperatures for best results.•Needs to be close to the national grid.•Plant needs safe location from storms and surf.

THANK YOU

PRAKASH JHA SANJEEV HALDAR RAJNARAYAN ROY RISHAV KUMAR SETHIA KAUSHIK DUARI SHUBHAM ROY GOURANGA SAW MD. SHAMSHER HOSSAIN RAVI PAL