It is well-known that nowadays major seawater desalination technologies need a great deal of fuels and electricity. With the growing shortage of fossil fuels, it will increase the cost of seawater desalination greatly. At present, cost is the main factor restricting the development of seawater desalination technology. And making use of fossil fuels will produce large amounts of carbon dioxide and pollutants, so as to speed up global warm environment. Taking the growing world energy shortage into consideration, it is urgent to search for new technologies for seawater desalination obviously today. Solar energy is a kind of clean energy which is limitless reserve and limitless use, and it will surely get the favor of people in seawater desalination technology aspect.
Solar energy seawater desalination is the process that separates water from salt in sea water to get fresh and concentrated water in the end, mainly by using solar energy light hot or photovoltaic (pv), which has very important significance to solve the current world energy crisis and shortage of freshwater resources. In case of no electricity, how to solve water resource and how to make use of solar energy seawater desalination, are the subjects of common concern around the world.
1. Solar battery reverse osmosis seawater desalination
one of the essential requirements of the equipment operation is the electric energy that is driven by high pressure pump. Solar energy power technology is applied on seawater desalination, making RO technology possible on the islands and desert areas without electricity. According to the local meteorological condition, if it is without external power supply it needs solar battery. Because of different Sunshine time and because of daily dose, electric energy production is also different, thereby it obviously affects the reverse osmosis production. When the meteorological condition causes insufficient electricity supply, it is advisable to employ battery power supply technology in order to maintain the normal water production.
2. Seawater desalination with the combination of solar and wind energy
For the island, it has the rich sea wind resource and relative stability of wind power. Wind power is one of the important energy desalination options. Two main kinds of wind power seawater desalination are wind driven directly seawater desalination and wind power seawater desalination. Wind driven directly seawater desalination can leave out “Mechanical energy – electricity – mechanical energy” conversion process, improve energy utilization efficiency and simplify the system structure.
Nevertheless, this technology is not suitable for large-scale seawater desalination plant, because of higher demand of seawater quality, ocean current, and ecology for seawater desalination plant. Wind power seawater desalination can be connected with power grid, also can not connected as an independent energy for desalination plant power supply directly. This system is suitable for large-scale desalination plant. The practice shows that wind power seawater desalination connected with power grid costs lower.
There are many advantages of solar seawater desalination. Firstly, it can run independently, not subject to steam and electricity, no pollution and low-energy, stable and reliable running, without consuming fossil fuel, quite valuable for environmental areas. Secondly, the scale of production can be organic combination, good adaptability, small investment, low water production cost, and has seawater supply market competitiveness.