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Surface outside solar radiation with reflections

asked 2020-03-03 08:19:15 -0500

Gustavobarea's avatar

updated 2020-03-03 08:43:47 -0500

Hello dear group, we are trying to calculate the solar radiation that comes directly from the sun (beam, diffuse and from the ground) in a plane with a specific inclination (Beta). As an input, we have all the weather data available from this place. We also have a reflective surface, like a mirror, that redirects the radiation and increases the solar gain in the first plane. We developed a "one thermal zone" + "shading group" sketch in E+ 8.4 but when we asked for output variables we only obtain values in those related to the inclined plane and only zeros in the radiation that theoretically comes from the reflective surface. Did anybody found a way to obtain how much radiation from the sun and the sky fall on a surface after bouncing a reflective surface? Thanks in advance, Regards!

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answered 2020-03-03 10:15:15 -0500

Be sure that the Solar Distribution input field of the Building object is set to an option that accounts for exterior reflections. This will tell EnergyPlus to account for the reflections off of the inclined mirror surface that would strike the first plane. You should also be sure to use the ShadingProperty:Reflectance object to tell EnergyPlus the diffuse and/or spectral reflectance properties of the mirror surface (if it's modeled as a shading surface and not a building surface like a wall).

The specific output variable that you are interested in depends on whether you drew the first plane as a shading surface object or a building surface object. If you run a simulation with the Output:VariableDictionary object included in the input file, EnergyPlus will generate the report data dictionary (RDD) file that shows the list of available output variables that you can examine. You can search here for "reflect" or "incident" or any other keyword you are interested in. If you want to have EnergyPlus generate that output variable of interest, create a new Output:Variable object with the same variable name.

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Asked: 2020-03-03 08:19:15 -0500

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Last updated: Mar 03 '20