I want to know more about sizing


I am currently doing some research on various heat and cool load calculations.

I’d like to do some research on solar radiation calculations, but I don’t know how to get a report on the amount of solar radiation on the design day.

Is it possible to use Honey Bee or EnegyPlus to provide a report of the solar radiation on the design day?

Thank you。


I’m not entirely sure I get what you wish to do, here are some tips you could start with:

Maybe this could get you started on a “surface level” (literally too):

You can use the Incident Radiation component in the LBT 1.x version, that gives an estimate on the radiation on your walls, windows, etc., you can use the results for further calculation in Grasshopper, or Excel, if you are only interested in the design day values.

You can read about EnergyPlus solar radiation calculation here:

The incident radiation is not telling much about the internal conditions:

To get a better understanding what happens when radiation is transmitted through the window, I recommend you skim through the documentation of the Window Calculation module:

It’s a deep dive… fortunately you can use simplified methods to account for aggregate window properties, but if you are interested in the effect of solar radiation on summer cooling- and winter heating energy reduction (I’m on the northern hemisphere), I cannot see a shortcut over this in the long run.

To model windows with shading (extremely important), you need to build an energy model with Honeybee, but that alone worth dozens of pages. I recommend you look through the examples on Hydra and search the forum for previous topics - how to setup windows, simple glazing, detailed glazing, how to assign shading, creating schedules for shading, modelling shading, determining whether windows are operable, etc. - all these properties are relevant to get a realistic report on solar radiation within a zone.

Is this what you are interested in?

Thanks for the reply.

I am checking the details of the calculation to compare EnergyPlus with another software in Japan.
The comparison shows that the load calculation by the Japanese software is clearly larger in terms of solar radiation.

This is the closest thing to what I’m concerned about.

However, I am having trouble calculating the annual graph but not the design day graph.

We would also like to know the “direct solar radiation” and “diffuse solar radiation” on the design day, not including buildings.

I found the link very helpful regarding the calculation logic.

Thank you.

Hi @Kaz,

It is possible to get the results of the solar radiation on a design day.
For more info you can have a look at this discusion.