There are two ways to generate electricity from ocean heat:
The first is to heat a low-boiling working medium to steam.
The second is to send warm water directly into a vacuum chamber and boil it to steam. The steam is used to drive a turbo-generator to generate electricity. It is then cooled to condense the steam from a depth of 600 to 1,000 meters.
The first is a closed cycle, the second an open cycle.
The first successful experiment in France, in 1930, failed to produce as much electricity as it consumed. At present, many countries are studying the temperature difference between seawater and electricity. Practice shows that the open cycle has more advantages than the closed cycle :0 using warm seawater as working medium can avoid toxic substances such as ammonia or dichlorodifluoromethane from polluting the ocean; @open cycle system has direct contact with heat exchanger, which is cheap and efficient; Direct contact heat exchanger can be made of plastic, high corrosion resistance in warm sea water; @ produces a byproduct - distilled water. Open cycle also has disadvantages: low steam density and large volume of steam turbine; When the water is returned to the ocean as steam, it can affect the living environment of nearby creatures.
It is a non-azeotropic medium (a mixture of freon -22 and freon -12).The trial operation of a 75-kilowatt test plant proved that the heat exchanger USES a flat panel device, which requires very little water to be pumped, consumes very little transmission power, and costs very little for other accessories. With computer control, the net power output can reach 70% of the rated power.A 3,000-kilowatt plant costs less than 50 yen per kilowatt hour, less than the price of diesel.It is expected that the use of ocean temperature difference power generation, if realized within a century, can be a new starting point for new energy development.
Tidal power generation:
Turbulent sea, in the sun and the moon under the effect of the tide, sometimes high tide, sometimes quietly receding, leaving a beach.The ocean rises and falls, day after day, year after year, so regularly, so rhythmically, as if one were breathing.This regular fluctuation of the sea water is known as tides.
Tidal power is an important way to use tidal energy.Preliminary estimates suggest that the world's tidal power could be more than 1 billion kilowatts, generating 2-3 trillion kilowatt-hours of electricity a year.China's coastline is 18,000 kilometers long.
According to the 1958 census, it is estimated that there are at least 28 million kilowatts of tidal power resources, and the minimum annual power generation is no less than 70 billion KWH.
The world famous high tide zone is the English channel, where the highest tidal range is 14.6 meters and the Atlantic coast ranges from 4 to 7.4 meters.The qiantang tide in hangzhou bay has a tidal range of 9 meters.
It is estimated that the north branch of the Yangtze river estuary alone can build 800,000 kw tidal power stations in China, generating 2.3 billion KWH of electricity annually, which is close to the total power generated by the xin 'an and fuchunjiang hydropower stations.The qiantang estuary can be built with a tidal power station of 5 million kilowatts, generating more than 18 billion kilowatt-hours of electricity annually, equivalent to the power generation capacity of 10 xin 'an hydropower stations.
As early as the 12th century, man began to harness tidal power.In the French coastal province of Brittany, tidal power has been used instead of human power.With the advance of science and technology, people began to build DAMS to retain water and build tidal power stations.
France has built the world's first large tidal power station in Brittany, a massive 750-metre dam topped by a road.The mean tidal range is 8.5 m and the maximum tidal range is 13.5 m.It generates 544 million kilowatt hours of electricity annually.
After the liberation of China, some small tidal power stations were built along the coast.For example, diliang tidal power station in shunde county, guangdong province (144 kw), huamui taigu tidal power station in xiamen, fujian province (220 kw), shashan tidal power station in wenling, zhejiang province (40 kw) and xiangshan gaotang tidal power station (450 kw).
Wave power generation:
The waves are a true reflection of the sea that never stops.Waves can be incredibly powerful, up to five meters high, with pressures of up to 10 tons per square meter.Big waves can hurl 13 tons of rock 20 meters high, turn over 1,700 tons of rock, and even push tens of thousands of tons of ships ashore.
The total energy contained in waves is staggering.It is estimated that the energy contained in the earth's waves is equivalent to 90 trillion kilowatt-hours of electricity.