How Solar Energy Works
Photovoltaic (PV) Solar Panels are a solid-state semiconductor device that converts sunlight directly into electricity. Usually they are made of silicon combined with other elements which are related to transistors liquid electronic devices (LED's), such as computer chips.
A Photovoltaic Solar Panel (solar cell or solar module) is made up of layers of semiconductor materials with different electronic properties. In an average solar crystalline silicon cell, the majority of the cell would be made of silicon, with just a small amount of boron to give it a positive character. Then it is coated in a thin layer of phosphorous on the front of the cell, with a non-reflective glass layer to create the negative character. This ultimately creates an electric field between the two layers, which is called the junction.
The photons (particles from light), hit the solar cell and some are absorbed in the area of the junction, freeing the electrons in the silicon crystal. If the photons contain enough energy, the electrons will converge the electric field at the junction and will move freely through the silicon atoms in the cell and move into an external circuit as energy. As they move through the external circuit they release their energy as electricity to either 'Off Grid', for all your daily household needs and charging batteries for use in the evening. Or 'On Grid' which can be sold back to the electricity utility company at an agreed price set over a period of usually 25 years, then return to the solar cell.
The photovoltaic process is an entirely self contained cycle with no moving parts and no materials being consumed or emitted, and with regular maintenance i.e. just keeping clean of dust and debris in many cases, can be up to 80-90% efficient for well over 40 years.
On a sunny day, an array of solar cells one square meter, exposed to the sun at noon will receive approximately 1 kilowatt (Kw) of power. NSI monocrystalline cells convert roughly 17.8% of this into electricity, meaning one square meter of cells will generate 178 electric watts in full sunshine.
Different solar cell technologies create varying conversion rates with amorphous silicon thin film creating around 6%-8%, cadmium telluride thin film 8%-10%, polycrystalline also referred to as multicrystalline silicon 12%-15% and monocrystalline 14%-19%. These efficiency rates are being pushed higher almost every year with new technologies and more efficient silicon’s.
At NSI we only produce monocrystalline and polycrystalline, let us explain the differences:
Monocrystalline solar cells are created from a single crystal and are cut from a block of crystal which has only grown in one direction (one plane). Single crystalline is more difficult to manufacturer, making a more expensive option with greater efficiency than the multicrystalline (polycrystalline cells).
Polycrystalline solar cells are created from a multifaceted crystal which is cut from a block of crystal grown in multiple directions, making them slightly less efficient for the same size cells, meaning having a larger surface area for the same output.
Amorphous Thin Film
Amorphous thin film panels are cheaper to manufacturer and the latest technologies are making them more efficient, pushing them up to over 130 watt barrier, but they require larger areas to produce the same quantity of energy.
At NSI we supply monocrystalline from 170Wp to 245Wp and polycrystalline from 200Wp to 280Wp, making our modules a more finically viable prospect
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