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How can I use energyplus weather converter to split global radiation in to direct normal and diffuse horizontal radiation

asked 2017-05-20 08:44:49 -0600

Amy Lee gravatar image

updated 2020-01-20 12:09:59 -0600

I'm trying to validate a building model by take into account the real weather situation. A onsite weather station had been installed.

But for solar radiation data,only global(total) radiation is available. From the auxiliary programs document,weather converter program, it seems the weather converter can use Perez split model to split the global into direct normal and diffuse horizontal values.

My questions is how can this be done using the weather converter? I do not find much useful related information yet.

If you had experience about this or done similar staffs before. Your suggestion is really appreciated.

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Good afternoon,

I would like to validate the building, but the EPW climate file I have only referred to climatic data of temperature, relative humidity, overall radiation. From what I perceive through the weather convert program it is possible to determine the diffuse horizontal and normal radiation.

In this way, I would like you to help me make a file to convert the radiation with the help of this program.

Please if you know how to solve this, it was very important to move forward with my master's thesis.

Thanks. gravatar image  ( 2017-09-21 10:34:26 -0600 )edit

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answered 2017-05-24 08:03:42 -0600

Repeating answer from helpdesk weather expert here. Read about the weather converter in the Auxiliary Programs document. With only Global Solar input, the program will automatically use the Perez model to split the global into direct and diffuse, which EnergyPlus needs.

You will need a "def" file that describes your input weather data. An example def file may be found here.

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Thanks a lot for your answer.

Amy Lee gravatar image Amy Lee  ( 2017-05-25 03:41:07 -0600 )edit


I try to read about weather converter in the Auxiliary Programs.

As @AmyLee said, I did not understand how EnergyPlus weather Converter can split the Global solar Input, it is not very helpful.

Maybe some more explaination will be helpful?

Thank you,

BORM gravatar image BORM  ( 2017-06-29 11:32:01 -0600 )edit

In the "def" file, the DataElements field specifies the contents of each column of the data file starting with column 1. If the weather data file only has global solar data, then this list will include only GloHorzRad (or Global Horizontal Radiation, long and short names are valid). When this data is processed, the Weather Converter will automatically split this into direct and diffuse.

MJWitte gravatar image MJWitte  ( 2017-07-03 07:32:38 -0600 )edit

Thanks Michael for your update.

I tried to delete direct and diffuse radiation in "DataElements", "DataUnits" and "DataConversionFactors" lists in def template file. But it will report errors when trying to deal with CSV weather file with direct and diffuse radiation column deleted. The only way I find can be successfully operating is to delete all the direct and diffuse radiation data in CSV while keep them in the def file lists.

BTW. it will be very helpful to have a checking list(like e+ error file) if there are errors occurred in the weather converting and the whole process crushed.

Amy Lee gravatar image Amy Lee  ( 2017-07-04 08:09:31 -0600 )edit

Hi Amy, I would really like to know how you made it work. I tried both your suggestions and it does not work for me. Could you provide your .def and .cst files that succeeded ? Thanks so much! @michael : I tried what you said and it does not work for me. Any other insights on that matter? I really think the documentation is lacking explanations on that matter ! Thanks everybody!

Aurore gravatar image Aurore  ( 2019-04-03 04:38:44 -0600 )edit

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Asked: 2017-05-20 08:44:49 -0600

Seen: 1,373 times

Last updated: Jul 03 '17