Conversion of solar energy
Sun - a gigantic light having diameter of 1392 thousand km. Its mass (2 * 1030 kg ) to 333 thousand times the mass of the Earth, and the volume of 1,3 million times the size of Earth. The chemical composition of the Sun: 81.76% hydrogen, 18.14% helium and 0.1% nitrogen. The average density of matter is equal to the Sun 1400 kg/m3. Inside the solar thermonuclear reactions occurring transformation of hydrogen into helium every second, and 4 billion kilograms of matter is converted to energy emitted by the sun in outer space in the form of electromagnetic waves of different lengths.
Solar energy people use since ancient times. Even in 212g. using concentrated sunlight lit the sacred fire at the temples. According to the legend about the same time, the Greek scientist Archimedes when defending his native city set fire to the sails of the Roman fleet.
Solar radiation - is an inexhaustible source of renewable clean energy.
Upper limit of the Earth's atmosphere for the year reaches the flow of solar energy in the amount of 5.6 * 1024 J. Earth's atmosphere reflects 35% of this energy back into space, and the remaining energy is expended on heating the earth's surface, evaporative-sedimentary cycle and the formation of waves in seas and oceans, air and ocean currents and wind.
The average amount of solar energy received for 1 day at 1m2 Earth's surface ranges from 7.2 MDzh/m2 in the north to 21.4 MDzh/m2 in the deserts and the tropics.
Solar energy can be converted into thermal, mechanical and electrical energy used in chemical and biological processes. Solar systems are designed for use in heating and cooling of residential and public buildings, in industrial processes occurring at low, medium and high temperatures. They are used to generate hot water, desalination of sea or mineralized water, drying materials and agricultural products, etc. Solar energy, the process of photosynthesis and plant growth, takes place various photochemical processes.
Known methods of the thermodynamic conversion of solar energy into electricity, based on the use of cycles of heat engines, thermoelectric and thermion emission processes, as well as direct methods of photoelectric, photovoltaic and photoemission change. Most practical applications have photovoltaic systems and the thermodynamic conversion using heat engines.
Solar energy is converted into electricity by solar power stations (SES), with equipment designed to capture solar energy and its successive transformation into heat and electricity. For effective work of the SEA is required battery of heat and automatic control system.
Capture and convert solar energy into heat by means of the optical system of reflectors and receivers of concentrated solar energy used to produce steam or heated gas or liquid metal coolant (working fluid).
For accommodation of solar power plants are best suited arid and desert zones.
On the surface of the largest desert of the world total area of 20 mln.km2 ( Sahara area of 7 million km2) for the year receives about 5 * 1016 kWh of solar energy. When the efficiency of converting solar energy into electrical energy, equal to 10%, sufficient to use only 1% of the desert areas to accommodate the SES, to ensure that the present world power consumption.