Radiant Asymmetry and MRT

Hey guys,

I'm trying to asses the local thermal discomfort related to radiant asymmetry. To do that I need to calculate the radiant asymmetry, which is done by multiplying surface temperatures with their view factor and summing it all together.

From what I can read this is basically the same way you calculate MRT right? So my question is can I replace t_pr in the equations of EN 7730-2006 with MRT?

If not is there a way to use HB's view factor component to calculate radiant asymmetry?

EDIT: I now see that you have to use radiant temperature asymmetry (delta_t_pr) and not t_pr for the EN calculation. Do anyone have an idea how to calculate that from the HB components?

Thanks,

Christian

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Replies to This Discussion

Permalink Reply by Chris Mackey on January 9, 2017 at 7:01am

Solon,
That part of the script is calculating the average window temperature on the window side of the plane, the average opaque temperature on that side of the plane, and is multiplying both by their respective view factors to get the total radiant temperature on that side of the plane. This temperature is compared with the temperature on the other side of the plane to estimate radiant asymmetry discomfort.
Let me know if this makes sense.
-Chris

Permalink Reply by Ian van Duivenbode on September 6, 2017 at 9:23am

Hi Chris,

Nice work with these components. Related to this part of the script, why do you multiply the view factor by 2?

Cheers

Ian

Permalink Reply by Chris Mackey on September 8, 2017 at 6:56am

Ian,

Good question and this actually got me to realize that there's a much cleaner way of calculating the radiant temperature on each side of the plane of the person. I was originally multiplying by 2 to convert the fraction of the sphere around the person to the fraction of the plane on either side of the person. Since a plane can only see up to half of a sphere, it has to be multiplied by 2 to be converted (or, to be technical, it actually has to multiplied by 2*cos(theta) where theta is the angle between a given view vector and the normal vector of the plane).

In any case, since the original creation of that example, I have added in the ability to automatically calculate plane view factors if you plug a plane into the _testPtsOrPlanes input of the Surface View Factor component (instead of a point). This means much less post processing of the results and a cleaner Grasshopper definition. So I have just updated the example here:

http://hydrashare.github.io/hydra/viewer?owner=chriswmackey&for...

Thanks for bringing my attention to this!

-Chris

Permalink Reply by Ian van Duivenbode on September 8, 2017 at 7:01am

Glad to help and many thanks for the update - ill have a play.

All the best,

Ian

Permalink Reply by Solon on January 31, 2017 at 12:24am