Solar tubes in DesignBuilder Daylighting

DesignBuilder does not have the solar tube objects, but the generic blocks are flexible and enable modeling extended geometry in a form of a solar tubes.

1. Use the Add surface tool to extrude a pipe shape from the ceiling to the roof level. 

If the pipe has a conical shape then these objects will need to be created using an Outline block. 

2. The Clone tool can be used to copy these objects and create an array of solar tubes. 

3. These tubes can then be converted to building block type (Convert Outline block option) and merged to the block below using Boolean operation with the Union option. 



4. Create the upper floors with an Outline block

5. Remove the block intersections by selecting the building block with the tube and the outline block.

6. Then, use Boolean operation with the Subtraction option to remove the intersecting section of the tube.

7. Use Convert Outline block option to convert the upper block to a Building block.



8. Apply a window on top of the solar tube geometry.


The final geometry should be similar to this:

Solar tube settings

The surface reflectance of the materials in the light pipe walls (partitions) needs to be set to a very high value as light pipe tubes are mirrors to reflect the light.

For Daylighting calculations you need to assign the suitable material properties under the Radiance Daylighting header of the innermost layer material on the Surface properties tab.

For further information please refer to the text from our DesignBuilder Program Help below:

Specularity

Enter a specularity value for the material surface to define the way that light reflects from it. The value entered must be between 0 and 1. A value of 0 provides purely diffuse reflection, while a value of 1 gives no diffusion, representing mirror-like behaviour.

Finally, use a high number of light bounces on your Daylighting simulations.