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Detailed radiation mode

4 Posts
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Topic starter

Dear TRNSYS users,

For using the detailed radiation mode it is stated in the manual that the zone has to be convex and closed.

I am modelling a greenhouse but i divided it to multiple zones which means that i had practicaly virtual zones all over the inside of the greenhouse. 

My question is : If a zone contains virtual surface does it mean that it is not closed ? and thus the detailed mode won't work ?

Because it does not work for me.

Kind regards.

Mohamed 

2 Answers
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Mohamed

The detailed mode should still work. When dealing with a situation such as yours, the idea is that you want to have multiple airnodes all contained within one radiation zone. When I have modeled greenhouses, I have sometimes stacked a few airnodes vertically so that I can get at the thermal stratification. The airnodes are separated from one another by virtual surfaces and all of them are assigned to a larger radiation zone that allows radiation to come into the top airnode and get all the way down to the bottom one. The radiation zone still has to be convex.

kind regards,

 David

 

0
Topic starter

David,

the difference is that i have zones separated by virtual surfaces horizontally and vertically.

i share with you my model, you will notice that once you choose the detailed radiation mode the error shows up (when  saving the building file) and you cannot generate the view matrix.

Thank you for your consideration.

 

Mohamed

DavidBradley 12/09/2023 4:33 pm

@sarmouk Mohamed, I don't see the model attached to your previous comment. In any case, I was able to make a test case in which I have two airnodes stacked on top of each other and a third one that sits beside both of the other two. All of the adjacent surfaces (three of them) in the model are set to "virtual surface" in Trnsys3d so they don't appear when the airnodes are imported into TRNBuild. In TRNBuild, I then added the airnodes called "ONE" and "THREE" to the airnode/zone called "TWO" and was able to generate the view factor.

As a side note, remember that when you have virtual surfaces "separating" airnodes, you have to click on the "coupling" button in the zone manager to define the flow rate of air that passes from one airnode to another.

kind regards,
David

DavidBradley 12/09/2023 4:35 pm

the *.idf file that I tried to attach got rejected...I am trying to attach a *.zip file.

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