Radiant heat gain from lights and equipment doesn't appear to be working

One of our energy modelers reviewed the idf files generated by Honeybee/OS and noticed a few issues. I’ve copied her comments into several posts, 1 per item.

#4 Radiant heat gain
The fraction radiant heat gain from equipment, light is something we would like to capture. Mostly the fraction radiant for electrical equipment is assumed between 20-30% and for lighting around 60%. Currently, the Electric lighting and equipment objects does not have any values for fraction radiant.

Model generated in HB/OS using custom equipment and lighting schedules

ASHRAE reference building idf. This is what we want.

in.idf (613.1 KB)
SchoolsFirstOffice.osm (724.7 KB)

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Hi Leland, I’ve just come across this same issue. Were you able to find a work around? I’m running some parametric simulations with a space which has a high density of electrical equipment and my cooling and heating load are not calculating properly. Going through to manually edit the IDF will not work for me since this is a parametric simulation.

@mschulte ,

The measure that I wrote and applied in this example file lets you set the fraction radiant for both lights and electric equipment:

When we release Honeybee[+] with energy modeling capabilities in a few months, the ability to set the fractions radiant and latent will be exposed in our Python API so you will be able to write a component to change this with just a couple of lines of Python. For now, though, the OpenStudio measure is the easiest way to go.