Parabolic Trough

Currently I’m building a low cost 1000mm x 2000mm parabolic trough for experimental purposes, which is split into four 1000mm x 500mm segments. Polished stainless steel is used as reflector material.

The tool used to calculate the support structure can be found here.

Up to now there are no building instructions here, but I will update the site from time to time.
If you are interested in more technical drawings please write a mail. If there are enough requests, I will upload further material.

Update 20110511:
A technical drawing (1:10) is now available: parabolictrough_technical_drawing

Update 20110508:
Today I did a series of tests, which should view the capability of the new mirror mounting.

Here are the results:
To get 700ml water to boiling temperature, one of the four modules (500mm x 918mm) took 7min.
If the absorber is preheated, the water already starts boiling in less than 5min.

The next test setup was filled with cooking oil to determine the maximum temperature of the module.
The highest temperature was 138°C after 4-5min with the poor, quickly black lacquered aluminium tube.

In my opinion it’s not that bad and I will continue to optimize the absorber.

Further steps are:

  • Try to get a ” cheap ” vacuum absorber tube. (DONE)
  • Try different materials for the tube.
  • Aluminium has good thermal conductivity (235W/(m·K)) but it is cooled down too fast by the fluid inside the tube and shadowing effects.
  • In my opinion it woud be better if the tube acts as a capacity and could store the heat, which could then be transmitted more steadily.

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