Frequently asked questions

General

What is Helios for?

Is Helios free of charge?

I have found a bug in Helios.

My photovoltaic power plant does not deliver the energy calculated by Helios.

Start and installation

Where are the start links?


What is Helios for?

Helios was primarily developed in order to create simple 3d scenes with primitive objects and calculate the shadow in this scene. Furthermore, the irradiated solar energy upon an arbitrarily oriented plane in the 3d scene can be calculated considering the shadow.

Typical use cases are the planning of the location of a photovoltaic solar power plant, the planning of cultivation or sun shades, or the visualization of the shadow as decision support when buying real estate.

Furthermore, Helios can be used to calculate the position of the sun and the various twilight phases for any place on earth.

In the shadow calculation, it is only considered whether the sun shines directly upon a certain point or not. Especially various effects like deep and half shadow, indirect illumination and so on, are not considered. If you want to create photo-realistic pictures of 3d scenes, you can try the program POV-Ray.

In the calcuation of the irradiated solar energy upon a certain point it is assumed that the point's horizon is not constrained. This means, if the point lies in the shadow, it is assumed that it gets the complete diffuse sky radiation during this time.

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Is Helios free of charge?

Yes and no. Helios is shareware. The demo version Helios Lite can be used temporally unlimited and free of charge, however, it has restricted functionality (e.g., a maximum number of five objects can be saved in the 3d scene). Under Order you can purchase the license for the full version Helios Pro. To this, please read also the Conditions of Use.

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I have found a bug in Helios.

If you notice a behaviour of Helios which seems faulty to you, you can report it to webmaster@schattenberechnung.de. The description of the bug should be as clear as possible and confined to the essential. An instruction how to reproduce the error is quite helpful here.

If a bug which cannot be fixed quickly is reported several times, it will be published on this page. Therefore, before reporting a bug it makes sense to check here whether it is already known.

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My photovoltaic power plant does not deliver the energy calculated by Helios.

The calculation of the radiation in Helios depends on several parameters like the fraction of the radiation which is reflected by the surface (albedo) or the degree of turbidity of the atmosphere (Linke turbidity factor). The most important influence has the duration of the sun shine during a month. Helios offers climatological mean values for different places in Germany. Naturally, these values can differ quite notably from the actual values of a particular year. If you want to verify the output of your photovoltaic power plant for a certain period, you should use the corresponding measured values of the duration of the sun shine (for Germany, these values can be downloaded from Deutscher Wetterdienst). In Helios, you can set any value for the duration of the sun shine for each month.

Further reasons for a discrepancy of calculated and measured values can be:

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Where are the start links?

In prior releases, Helios could be started by Java Webstart, which was a comfortable way to install the correct version of Java including all needed libraries. However, there were many reports that this mechanism did not work as intended. Therefore, Helios is now distributed as installer file, so that Helios can be installed like a normal Windows program.

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