Re: [TRNSYS-users] Type68 shading

[David Bradley <bradley@tess-inc.com>]

Stefan,
  One of the restrictions of Type68 is that the obstruction azimuth
angles must be evenly spaced between -180 and 180 degrees absolute angles
(in other words not relative to the window). The only thing that you are
able to choose is the angle step size. A 22.5 degree step size would
result in a data file line of:

-180.0 -157.5 -135.0 -112.5  -90.0  -67.5  -45.0 
-22.5    0.0   22.5   45.0  
67.5   90.0  112.5  135.0 
157.5    

for azimuth angles that are behind the view angle of the window, you can
simply enter a value of 0 for the obstruction height. Type68 calculates
the effective obstruction height internally if you do not set it
yourself. In the most recent release of the code (16.00.0038, June 2005),
Type68 was modified so that it produces an error if it runs into problems
with the specified azimuth angles.
Kind regards,
 David


At 09:37 2/17/2006, Stefan de Kool wrote:

Dear all,
 
I have 2 horizontal windows, shaded by the same object, but from different angles, so I use two Type68 shading masks (one with 6 and one with 7 azimuth angles). I don?t trust the results however because when I set one of the obstructions to zeros (all betas = 0), the beam radiation is ok (equal to solar radiation) but the diffuse radiation is less than the diffuse radiation output from type16. As trnsys does not now the relative position of the windows (as far as I can see), I do not see why this would happen. Has anyone any suggestions? Below are the obstruction files I use (for debugging I set one to all-zeros and the other to all 100, these are not the actual values of the obstructions)
 
obstructionA.dat:
-------------------------
1
0
0
33 33 40 90 155 155
100
100
100
100
100
100
 
 
obstructionB.dat:
------------------------
1
0
0
18 18 15 25 70 88 88
0
0
0
0
0
0
0
 
 
Met vriendelijke groeten,
Stefan de Kool
 
Cauberg-Huygen Raadgevende Ingenieurs
Lokatie Rotterdam
 

 


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