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ENERGY FROM THE SUN. APPLICATIONS OF SOLAR TECHNOLOGY. INDEX. Solar thermal collectors Solar and photovoltaic cells Photovoltaic panels Photovoltaic performance. WHAT IS SOLAR ENERGY?.
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ENERGY FROM THE SUN APPLICATIONS OF SOLAR TECHNOLOGY
INDEX • Solar thermal collectors • Solar and photovoltaic cells • Photovoltaic panels • Photovoltaic performance 2°C Liceo Scientifico A. Oriani, Ravenna
WHAT IS SOLAR ENERGY? • Solar energy is the radiant light and heat from the sun which has been harnessed from humans since ancient times using a range of ever-evolving technologies. • Only a minuscle part of solarenergy is used. 2°C Liceo Scientifico A. Oriani, Ravenna
USES AND APPLICATIONS • Solar power technologies provide electrical generation by means of heat engines or photovoltaics. A partial list of solar applications includes space heating and cooling through solar architecture, potable water via distillation and disinfection, hot water, thermal energy for cooking. 2°C Liceo Scientifico A. Oriani, Ravenna
ACTIVE AND PASSIVE SOLAR TECHNOLOGIES Solar technologies are divided in passive solar and active solar. Active solar techniques include the use of photovoltaic panels and solar thermal collectors to convert sunlight into useful outputs. Passive solar techniques include orienting a building to the Sun or selecting materials with favorable thermal mass or light dispersing properties. 2°C Liceo Scientifico A. Oriani, Ravenna
ENERGY FROM THE SUN The Earth receives 174 petawatts of incoming solar radiation at the upper atmosphere. Approximately 30% is reflected back to space while the rest is absorbed by clouds, oceans andland masses whose temperature rises. By photosynthesis green plants convert solar energy into chemical energy, which produces food, wood and the biomass from which fossil fuels are derived From the table of resources it would appear that solar, wind or biomass would be sufficient to supply all of our energy needs. 2°C Liceo Scientifico A. Oriani, Ravenna
SOLAR THERMAL COLLECTOR is a solar collector specifically intended to collect heat device for extracting the energy of the sun directly into a more usable or storable form. 2°C Liceo Scientifico A. Oriani, Ravenna
Typologies • Flat plat • Evacuated tube • Pool or unglazed • Asphalt Solar Collector • Volumetric thermal collectors 2°C Liceo Scientifico A. Oriani, Ravenna
It’s the most common type of solar thermal collector It’s usually used as a solar hot water panel to generate solar hot water. It’s generally used in hotels and homes in sunny climates such as those found in southern Europe. Flat plat 2°C Liceo Scientifico A. Oriani, Ravenna
Evacuated tube can perform well in colder conditions. The high temperatures that can occur may require special system design to avoid or mitigate overheating conditions. Has multiple evacuated glass tubes which heat up solar absorbers. 2°C Liceo Scientifico A. Oriani, Ravenna
It is much like a flat-plate collector. Pool or unglazed • It is used extensively for pool heating. • It becomes ineffective when the ambient temperature gets cooler. 2°C Liceo Scientifico A. Oriani, Ravenna
It collects heat using fluid circulating through an array of pipes embedded n the surface of a road. Asphalt Solar Collector 2°C Liceo Scientifico A. Oriani, Ravenna
Volumetric thermal collectors • They use principle of volume absorption with modern designs that include vacuum insulation. • They are the oldest method of getting heat from the sun. 2°C Liceo Scientifico A. Oriani, Ravenna
Advantages Very high temperatures reached Good efficiency A larger area can be covered by using relatively inexpensive mirrors Cheaper than photovoltaic modules 2°C Liceo Scientifico A. Oriani, Ravenna
Disadvantages Concentrating systems require sun tracking to maintain Sunlight focus at the collector Inability to provide power in diffused light conditions Power output drop drastically in cloudy conditions as diffused light cannot be concentrated passively. 2°C Liceo Scientifico A. Oriani, Ravenna
Photovoltaic cells A solar cell, also called a photovoltaic cell, is used to convert solar energy into electrical energy
How do they work? • Solar cells are made using semiconductors such as silicon ; • When particles of light are absorbed by the semiconductor, they transfer their energy to some of the semiconductor's electrons. 2°C Liceo Scientifico A. Oriani, Ravenna
Advantages • Solar cells are also totally silent and non-polluting ; • Solar cells require very little maintenance, greatly because there are no moving parts that must be maintained; • Solar cells can last a lifetime. 2°C Liceo Scientifico A. Oriani, Ravenna
Disavantages • Solar energy systems do not work at night; • Solar cells are currently costly and require a large initial capital investment; • For larger applications, many photovoltaic cells are needed, corresponding to high investment costs and large land requirements; • The cost effectiveness of a solar energy system is dependent upon the location and climate. 2°C Liceo Scientifico A. Oriani, Ravenna
Usage of solar cells The semiconductor most widely used in solar cells is single-crystal silicon. Cells produced by this method are prohibitively expensive for all but the smallest scale or most specialised applications 2°C Liceo Scientifico A. Oriani, Ravenna
PV PERFORMANCE We have the best performance, with these conditions: High noon Cloudless day In the equator } The insolation is about:1 Kw/m²
The Real PV performance In Earth, the real PV performance is about: Or with the best commercially available panels Is about 20% 12% of the hypothetic performance Also, to obtain the best PV performance,the solar panels, in Northern Hemisphere are point due sud, whereas, in Southern Hemisphere are point due north.
PHOTOVOLTAIC ENERGY SOLAR ENERGY ELECTRICITY It is the field of technology and research related to the application of solar cells for energy by converting sunlight directly into electricity 2°C Liceo Scientifico A. Oriani, Ravenna
From the smallest part of photovoltaic energy Solar panels The solar cell To a composition of solar cells 2°C Liceo Scientifico A. Oriani, Ravenna
Liceo Scientifico “A. Oriani” RavennaInterdisciplinary projectSubjects involved: English, Physics, Information TechnologyTeacher involved: prof.ssa Siboni Elisabetta and prof.ssa Laurena Petrizzi Class II C PNI 2°C Liceo Scientifico A. Oriani, Ravenna