Currently, I’m building a low cost 1000mm x 2000mm parabolic trough (used for example at Desertec) 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.
A technical drawing (1:10) is now available: parabolic trough_technical_drawing
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 aluminum 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.
See also the Parabola Tool if you want to build your own.