Reflectometry
The importance of solar electricity generation
With fears of carbon dioxide causing global warming and diminishing supplies of fossil fuels, a looming energy crisis is affecting all countries. As a consequence, a great deal of world-wide effort is going into the development of alternative energy technologies. At present, wind, hydro and geothermal are becoming well established with more niche roles for tidal and solar. The latter technology has two common forms, firstly solar water heating, and secondly photo voltaic (PV) solar electricity generation.
Solar water heating Reflectometry
For domestic hot water needs, solar hot water is starting to make significant inroads in Europe and Turkey but very little impact in the rest of the world, with the exception of China. This country has more than 70% of the world's solar water heating capacity, assisted greatly by government subsidy and promotion. (REN21 Renewables 2010 Global Status Report)
Photovoltaic Solar electricity
PV Solar from the above mentioned report shows a different picture, with Germany having the dominant usage at 47%, whereas China had less than a few percent at the end of 2009. However, whilst the power from PV in total is no more than about 15% of that of solar water, its use is spread more evenly throughout the world.
There is much research into new and improved photo voltaic technologies as well as rapidly increasing use of existing commercial products. Traditionally the cost per watt of this technology has far exceeded that of conventional power generation and not surprisingly the main development thrusts are increase in efficiency and reductions in cell costs.
The operation of a PV solar cell is based on the photovoltaic effect, when the capture of a light photon photoexcites an electron to a higher energy level. The cell is constructed as a PN junction from semi-conductor material, like the common diode, in which photoexcited electrons preferentially diffuse across the junction barrier and flow around an external circuit providing power.
Silicon single crystal solar cells
Traditional cells are made from single crystal Silicon or c-Si and produce about 0.5Volts per cell, with typical power efficiency of 15-17%. The maximum theoretical efficiency of conversion from light energy to electrical energy is about 30% and recent developments have produced examples exceeding 24%. Clearly, with an output of a mere 0.5V, numerous cells have to be connected together to produce enough voltage to work with. This is done in the solar panel where the cells are arranged in a matrix, encapsulated in transparent EVA, usually behind a glass front cover and sealed into an outer frame. The back of the panel is sealed with a polymer Reflectometry , selected for its electrical insulation, toughness, and importantly, lack of water permeation. These devices are expected to last for 25 years or more and corrosion damage to the electrical contacts by water is one of the biggest threats.
tag : Reflectometry
The importance of solar electricity generation
With fears of carbon dioxide causing global warming and diminishing supplies of fossil fuels, a looming energy crisis is affecting all countries. As a consequence, a great deal of world-wide effort is going into the development of alternative energy technologies. At present, wind, hydro and geothermal are becoming well established with more niche roles for tidal and solar. The latter technology has two common forms, firstly solar water heating, and secondly photo voltaic (PV) solar electricity generation.
Solar water heating Reflectometry
For domestic hot water needs, solar hot water is starting to make significant inroads in Europe and Turkey but very little impact in the rest of the world, with the exception of China. This country has more than 70% of the world's solar water heating capacity, assisted greatly by government subsidy and promotion. (REN21 Renewables 2010 Global Status Report)
Photovoltaic Solar electricity
PV Solar from the above mentioned report shows a different picture, with Germany having the dominant usage at 47%, whereas China had less than a few percent at the end of 2009. However, whilst the power from PV in total is no more than about 15% of that of solar water, its use is spread more evenly throughout the world.
There is much research into new and improved photo voltaic technologies as well as rapidly increasing use of existing commercial products. Traditionally the cost per watt of this technology has far exceeded that of conventional power generation and not surprisingly the main development thrusts are increase in efficiency and reductions in cell costs.
The operation of a PV solar cell is based on the photovoltaic effect, when the capture of a light photon photoexcites an electron to a higher energy level. The cell is constructed as a PN junction from semi-conductor material, like the common diode, in which photoexcited electrons preferentially diffuse across the junction barrier and flow around an external circuit providing power.
Silicon single crystal solar cells
Traditional cells are made from single crystal Silicon or c-Si and produce about 0.5Volts per cell, with typical power efficiency of 15-17%. The maximum theoretical efficiency of conversion from light energy to electrical energy is about 30% and recent developments have produced examples exceeding 24%. Clearly, with an output of a mere 0.5V, numerous cells have to be connected together to produce enough voltage to work with. This is done in the solar panel where the cells are arranged in a matrix, encapsulated in transparent EVA, usually behind a glass front cover and sealed into an outer frame. The back of the panel is sealed with a polymer Reflectometry , selected for its electrical insulation, toughness, and importantly, lack of water permeation. These devices are expected to last for 25 years or more and corrosion damage to the electrical contacts by water is one of the biggest threats.
tag : Reflectometry
