Classify the solar collectors and compare them.
Classification of solar collectors :-
1. There are two main types of Flat Plate type collectors :- a) Flat plate collectors (FPC) b). Evacuated Tubular collector (ETC)
2. Concentrating type collectors (focusing type collector): There are three main types of concentrating solar power system
Line Focusing: - 1) Linear cylindrical Parabolic (troughs) concentrating collector
Point Focusing: - 2) Central receiver Spherical (Dish) Parabolic concentrating Collector 3) Central receiver solar tower with number of distributed Concentrating collector.
Points
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Flat plate collector
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Concentrating type collector
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Shape
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Shape of collector is rectangular
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Shape o collector is parabolic or disc type / Tower
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Collector and absorber area
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The Collector area is same as absorber area
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The Collector/reflector area is more than absorber area
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Design
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Mechanically simple in design
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Complicated in design
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Construct
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Are relatively simple to construct and erect
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Difficult to construct and erect
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Tracking
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No tracking of panel is required to words sun direction
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Tracking is required to words sun direction for better results
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Uses of sun radiation
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It uses both direct and diffused radiation of sun
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It uses only direct radiation of sun because diffused radiation cannot be reflected.
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Flux
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Uniform flux on the collector & absorber
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Non-uniform flux on the collector & absorber
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Cloudy days
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Effective even cloudy days when there is no direct radiation of sun
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Ineffective in cloudy days as there is no direct radiation of sun
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Heat losses
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Heat losses are more (as absorber area is more)
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Heat losses are less (as absorber area is less)
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Efficiency
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Efficiency is less
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Efficiency is high
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Temperature obtain
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Temperature obtain is less (up to 900C)
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Temperature obtain is high (up to 4000C)
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Heat insulation cost
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Heat insulation cost is more
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Heat insulation cost is less
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Maintenance
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Little maintenance
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More maintenance
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Space required
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Space required is less
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Space required is more
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Anti-freeze protection
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It require more anti-freeze protection
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Little or no anti-freeze protection is require to protect the absorber
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Generate steam
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Not suitable to generate steam only for heating water/fluid/Air
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Suitable to generate steam
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Generate electricity
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Cannot be used to generate electricity directly from water
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Can be used to generate electricity with the help of steam turbine
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