Parabola Tool

This tool will help you to design a parabolic trough and give you the information you will need to build a simple one on your own.
Download ParabolaTool_v190

ParabolaTool v1.9:

Compiled without source code guarding. Exe will start correctly on machines without additional DLLs.

ParabolaTool v1.8:

Export functions are available now.

ParabolaTool v1.7:

By ” Print 1:1 ” functionality you are now able to plot the parabola at its real size and to use it as a template for cutting the beams or to cut a solid beam.

Reflector Width:

You can enter the width of the reflector here. (Real/plain width of the mirror)

Supporting Beams:

To stabilize the parabolic shape, it is useful to place some supporting beams along the curve. The middle is always fixed to x=0 and the outer one to the highest point of the reflector.

Focal Point Height:

Parabola Tool calculates the curve by selecting the damping of the parabola. The height of the focal point is the most important variable you have to select to get good results. The higher this value is, the lower are the shadowing effects. Keep in mind that this will also increase the vulnerability to inaccuracy. A good starting point should be 30cm-1m for 1m x 2m base frames and 3/4 ” absorbers.

Parabola Width:

Is the shortest distance between both ends of the reflector. You can use this as a starting point for the width of the base frame.

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.