Thank you for visiting Solar Energy News. It's my hope that this site will help promote the use of Solar Energy, and reduce dependency of Oil and other non-renewable forms of energy.
What is solar energy?
Solar Energy is heat formed by nuclear fusion reactions deep in the Sun’s center The Sun gives almost all the heat and light the Earth receives and therefore sustains every living organism.
Sunlight or the solar energy as you know it can be a source to produce electricity, provide hot water, and to heat, cool, and light buildings. This is a dream many have had through the past few decades in an effort to solve the Earth’s energy problem.
This energy travels to Earth through space in discrete packets of energy called photons. On the side of Earth facing the Sun, a square kilometer at the outer edge of our atmosphere receives 1,400 megawatts of solar power every minute, which is about the capacity of the largest electric-generating plant in Nevada. Only half of that amount, however, reaches Earth’s surface.
The atmosphere and clouds absorb or scatter the other half of the incoming sunlight. The amount of light that reaches any particular point on the ground depends on the time of day, the day of the year, the amount of cloud cover, and the latitude at that point. The solar intensity varies with the time of day, peaking at solar noon and declining to a minimum at sunset. The total radiation power which is 1.4 kilowatts per square meter, called the solar constant, varies only slightly, about 0.2 percent every 30 years. Any substantial change would alter or end life on Earth as we know it.
The solar power, which reaches the Earth, is consumed for more or less 30 percent by the continuous circulation of water. This system is called the water cycle or hydrologic cycle. The Sun’s heat evaporates water from the oceans. Winds transport some of the water vapor from the oceans over the land where it falls as rain. Rainwater seeps into the ground or collects into streams or lakes and eventually returns to the ocean. As a result, radiant energy from the Sun is transformed to potential energy of water in streams and rivers.
People can tap the power stored in the water cycle by directing these flowing waters through modern turbines. Power produced in this way is called hydroelectric power.
There are lots of buildings and houses now that uses solar energy to make hot water. However, most large edifices use these solar collectors/energy to provide more than just hot water. Solar process heating systems can be used to heat these buildings. A solar ventilation system can be used in cold climates to preheat air as it enters a building. In addition, the heat from a solar collector can even be used to provide energy for cooling a building.
A solar collector is not always needed when using sunlight to heat a structure. Some structures can be designed for passive solar heating. These structures usually have large, south-facing windows. Materials that absorb and store the sun's heat can be built into the sunlit floors and walls. The floors and walls will then heat up during the day and slowly release heat at night. Many of the passive solar heating design features also provide daylighting. Daylighting is simply the use of natural sunlight to brighten up a building's interior.
A Photovoltaic or the so-called solar cell systems change sunlight directly into electricity. A solar or PV cell consists of semi conducting material that absorbs the sunlight. The solar energy knocks electrons loose from their atoms, allowing the electrons to flow through the material to produce electricity. PV cells are typically combined into modules that hold about 40 cells. About 10 of these modules are mounted in PV arrays. PV arrays can be used to generate electricity for a single building or, in large numbers, for a power plant.
A power plant can also use a concentrating solar power system, which uses the sun's heat to generate electricity. The sunlight is collected and focused with mirrors to create a high-intensity heat source. This heat source produces steam or mechanical power to run a generator that creates electricity.