WUFI

Dear support,

The orientation of a vertical construction has no influence on the temperatures. It seems that a south orientation is the default, and setting the azimuth to e.g. 180 has no influence on the results (temperatures still go up over 60 C for a north orientation in the test case, see attached). I'm using WUFI2D 4.4.0.192. Please help.

Kind regards.

I noticed that results for other than south orientation can be obtained by saving the project (with the other orientation),restarting WUFI and re-opening the project. However, again, when changing the orientation, no differences can be observed in the results. So, every time I want to simulate another orientation, I have to save, close and restart WUFI.

Hi Willem,

unfortunately, you have encountered a bug in WUFI-2D. Apparently the problem is caused by WUFI-2D failing to update the file with the boundary conditions. For performance reasons, WUFI-2D creates a file *.bcli ("binary climate") which contains the pre-processed boundary conditions (with the solar radiation data transformed to the specific orientation and inclination of the surface, etc.) If a change has been made to one of the boundary conditions, the respective .bcli file should be updated when the "Processing" tab is opened, but it seems that in certain cases WUFI-2D fails to notice that a change has been made.

In your case, this concerns the file "Exterior_Surface.bcli" which contains the pre-processed data for the boundary condition "Exterior_Surface" and can be found in WUFI's cache directory. (See the program settings for the location of the cache directory, if you are interested. See the item "directories" in the Glossary of the help file for a discussion of how the cache directory wotks, if you are interested). By looking at the timestamp
of the file you can see whether it has been updated or not.

I have found the following three possible workarounds to induce an update of the .bcli file:

After having changed the orientation ...

(1)
... save the project and re-open it (the menu item 'Reopen' keeps a list with the project files used recently).

The re-opened project will contain the old .bcli file, but as soon as the 'Processing' tab is opened, WUFI will update the file.

It is not necessary to restart WUFI.


or (2)

... press CTRL+W to write the memory contents to the cache directory, making sure that the cache directory contains the current state of the project.

Delete the .bcli file for the relevant boundary condition (in this case, 'Exterior_Surface.bcli' since the name of the boundary condition is 'Exterior_Surface'.)

Then go to WUFI's File menu and 'Revert to last cached'.

This will read the cache contents into memory; WUFI will notice the missing .bcli file and re-create it, using the current project data.


or (3)

... also change the "Temperature Shift" entry in the "Details..." window of the climate dialog to a different number. Assign the boundary condition as usual, and open the Processing tab. In this case, WUFI will notice that a change has taken place and will update the .bcli file.

However, since you probably don't really want a temperature shift, you'll have to go to the boundary conditions a second time and set the shift back to zero (or whatever you want). This second change will cause another update, but the important thing is that the orientation has been included in the updates. (In the case of the "temperature shift", WUFI notices that a change has occurred, so this workaround uses it as a tool
to alert WUFI that the .bcli file should be updated.)


.
The .bcli files should be updated whenever a change occurs which affects the pre-processed climate files. This includes for example a change of the starting date of the calculation or a change of the time step size. An un-updated .bcli file may then lead to inconsistent results.

Kind regards,
Thomas