[TRNSYS-users] Surprising phenomenon with Type 67

[David Bradley]

David,

>I've realised the following experience: I've 
>used Type67 without shadings (angular height 
>equal to 0°) and Type34 without shadings 
>(overhang projection and wingwalls projection equal to 0).
>Direct and diffuse radiation should not change. 
>Actually, diffuse radiation vary. It's sometimes 
>even greater after Type34 than before!

this happens because Type34 assumes an isotropic 
sky whereas Type109, Type15, or Type16 give you a 
choice of what sky model you use. If you set the 
component that is reading and processing your 
solar radiation data to use the isotropic sky 
model, you will see the same amount of diffuse 
radiation into and out of type34.

>2 - In angular obstruction data files, for 
>angles directed inside the building (eg 0° for 
>North orientation), which angular height should 
>be used? (0°, 90°, it doesn' matter?)

it doesn't matter. Type67 calculates the angular 
heights for angles directed inside the building 
and corrects them if the data file is wrong. I 
personally prefer to enter values of 90° for 
those angles so that the data file is coherent.

>5 - I cannot use more than 20 orientations with 
>type 67 eventhough the max is 40 in the proforma. Can you help me?

that is probably because the Type67 fortran code 
has a lower setting (MAXANGS). Are you able to 
recompile the TRNDll.dll yourself? If not, we can provide you with a new one.

>6 - Besides, I did not manage to use 2 type 67 
>at the same time. I made a few tests using 2 
>type 67 and it always generate an error of 
>reading of the external file, while both types 
>67 work alone. Is there a bug somewhere?

that does sound like a bug. Are you using the 
latest version of TRNSYS (16.01.0003)?
Cheers,
  David


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