How can TRNSYS calculate direct and diffuse solar radiation given an average global radiation?

asked 2020-10-12 08:56:14 -0600

Niloufar mousavi
31 ●3 https://www.linkedin.c...

updated 2020-10-25 19:23:02 -0600

I am doing a simulation based on an experimental module and I have an average hourly global radiation but I need at least to estimate the diffuse portion of it or direct radiation for my specific station. I read that TRNSYS can calculate direct and diffuse solar. But I don't know how.

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answered 2020-10-14 09:09:06 -0600

Tim McDowell
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TRNSYS has a radiation processor component that calculates direct/diffuse horizontal and tilted surface solar radiation. The component has different modes based on the input information that is available. There are two modes that use global horizontal as an input. One includes no other information and the other also uses the ambient temperature and relative humidity. The direct/diffuse split is determined based on the clearness index and solar altitude angle using relationships developed by Reindl (Reindl, D.T., Beckman, W.A. and Duffie, J.A., “Diffuse Fraction Correlations”, Solar Energy, Vol. 45, No. 1, (1990), pp.1-7.)

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Thank you so much Tim, Do you know any link that has tutorial on how to input using the second method?

Niloufar mousavi ( 2020-10-14 10:51:53 -0600 )edit

The radiation processor component has a mode parameter than indicates what information will be input to the component to be used to calculate the solar radiation.

Tim McDowell ( 2020-10-21 14:47:26 -0600 )edit

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answered 2020-10-25 18:22:19 -0600

Niloufar mousavi
31 ●3 https://www.linkedin.c...

I found it and I am gonna write here for anyone else who has the same issue. If you have real weather data of total radiation, you can use TRNSYS input type 9C and processor 16C which is mode 2 if you also have the ambient temperature and humidity as well.