SOLAR ENERGY

Solar energy is often called "alternative energy" to fossil fuel energy sources such as oil and coal.

Solar energy is radiant energy produced in the Sun as a result of nuclear fusion reactions. It is transmitted to Earth through space in quanta of energy called photons, which interact with the atmosphere and surface. The intensity of solar radiation at the outer edge of the atmosphere, the earth is the average distance from the sun is called solar constant, whose value is 1, 37 * 106 or about 2 cal/min/cm2 ergs/sec/cm2. However, the intensity is not constant, it varies by approximately 0, 2 percent in 30 years. Solar intensity at Earth's surface is less than the solar constant, solar energy due to uptake and diffraction, the photons interact with the atmosphere.
Solar intensity at any point on Earth depends in a complicated but predictable, the day of the year, an hour, for up point.Furthermore, the amount of solar energy can be absorbed depends on the orientation of the draws.
Natural absorption of solar energy occurs in the atmosphere, oceans and plants. Interaction of solar energy, oceans and atmosphere, for example, produces winds that for centuries was used windmills. Modern uses of wind power machines require powerful, lightweight, aerodynamic design, resistant to all weather conditions, which attached to generators produce electricity for local, specialist or as part of a local or regional distribution networks.
About 30% of solar energy reaching the edge of the atmosphere is consumed in the hydrologic cycle, producing rain and the potential energy of water in mountain streams and rivers. The power produced by these rivers as they pass through modern turbines is called hydroelectric power. The process of photosynthesis, solar energy contributes to increasing biomass, which can be used as fuel including wood and fossil fuels that were formed from plants much disappeared. Fuels such as alcohol or methane can also be extracted from biomass.
The oceans represent a natural form of energy absorption. As a result of solar energy uptake in the oceans and ocean currents, temperature varies a few degrees. In some places, these variations vertical approaches 20 (C for a few hundred meters away. When large masses of water have different temperatures, thermodynamic principles predict that a power generation circuit can be created by taking energy from the mass with higher temperature and transferring a small amount of energy with lower temperature. The difference between these two caloric energy manifests as mechanical energy, which can be connected to a generator to produce electricity.
Direct capture of solar energy involves artificial means, called solar collectors, which are designed to capture energy, sometimes by focusing direct sunlight. Energy, once captured, is used in thermal processes, photoelectric or photovoltaic. In thermal processes, solar energy is used to heat a gas or liquid which is then stored or distributed. The photovoltaic process, solar energy is converted directly into electricity without using intermediate mechanical devices. Photoelectric processes are used mirrors and lenses that captures sunlight to a receiver, where solar heat is transferred to a fluid put in operation a conventional electric power conversion.
Next we present some of these solar power devices:Solar panels
Collector fluid channels passing through the solar panel temperature is increased due to heat transfer. Energy transferred is called fluid bearer instant collector efficiency.Solar panels generally have one or more transparent layers to minimize heat losses and to obtain an efficiency as possible. In general, are able to warm up the fluid collector 82 (C with a yield between 40 and 80%.
These solar panels have been used effectively for heating water and homes. They replace the roofs locuinþelor. In the northern hemisphere, they are facing south, while the southern hemisphere are facing north. Optimal angle depends panels fitted up to found The device in question. Generally, the devices used year-round, the panels are tilted at an angle equal to latitude gather or minus 15 (and are oriented north to south respectively).
In addition, solar panels used to heat water or houses present pumps, temperature sensors, automatic controllers that activate pumps and energy storage device.