[TRNSYS-users] Type-538, IAM's, Cos Phi and DNI

[José María Roca]

Hello Community, hope you are all great!

I have a question regarding all of the above things, and how they are related.

I was modelling a parabolic trough using the type 538 that has more flow control strategies than the 536. However I was presented with some questions down the road.

I’m attaching the test report from SPF of the said parabolic collector.

My doubts regard the efficiency curve parameters, IAM’s and incidence angle or Cos Phi effect.

The type's source code has the following for the incident radiation at the aperture:
“
...
!Calculate the total incident solar radiation

 Gtotal=IAM_Beam*Beam_Radiation+IAM_Diffuse_Sky*SkyDiffuse_Radiation+IAM_Diffuse_Ground*GroundReflDiffuse_Radiation
...
“

So, if I’m using the efficiency parameters for the DNI, the IAM_Beam should include the Cosine effect since the DNI has cosine = 0 and Beam_Radiation would be DNI.

If in turn, i’m using the efficiency for the Total incident radiation, that has a smaller optical efficiency (same first and second order loss coeff) the IAM_Beam should not include the Cosine effect since apparently the optical efficiency already has considered this effect and the Beam_Radiation is actually the Beam and not the Normally incident.

The other question that I could not answer is about the IAM curve on the test report, does it include cosine effect?

If any one has a heads up on this I would very much appreciate the feedback.

Best!
José María Roca



 
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