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How do I know the produced heat on the focal point of a solar parabolic trough per different radius if made from steel and also from glass?

Vishnu JK
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MAHMOUD NEJAD
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1 Answers1

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Your question is not very well formed - here are some considerations:

  1. incident power from the sun is about 1.3 kW / m$^2$ for normal incidence with the sun overhead, no clouds. Depending on the orientation and dimensions of your trough, you should be able to compute the maximum power collected
  2. If you make the trough of steel or glass, the reflectivity will be less than 1.0 - this means that not all the incident power is reflected to the focus (some will heat up the reflector)
  3. The collector will not absorb all the radiation (it is not "perfectly black") - this means it will reject some of the incident power
  4. As the collector heats up, it will become a radiating black body

A lot of this can only be estimated by measurement. Lucky for you, somebody did the measurements, and published the result here. They suggest an efficiency of about 77% is possible.

Floris
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