Grasshopper

algorithmic modeling for Rhino

Evaluating internal thermal comfort accounting for incident radiation on user

Dear All,

Assuming we want to evaluate the thermal comfort conditions for occupants in a building, is there a way in Honeybee to take into account, in the comfort evaluation, the radiation entering the building through glazed facades and incident on an occupant?

In summary, is it possible to account for the fact that a person next to a glazed facade will be exposed to incident radiation?

I assume for the moment the fact that the mean radiant temperature extracted from the results is only taking into account the effect of solar radiation absorbed by the surfaces (also glazing) of the building.

Although, I would like to understand what is the additional effect of direct solar radiation on building occupants.

I am not sure whether there is already a discussion answering specifically to this question. In case there is, could you please share the link to it?

Many thanks,

Carmelo

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Hi Carmelo,

All studies that you run using the Honeybee microclimate maps will automatically account for solar radiation falling directly on occupants and the subsequent increase in occupant MRT as a result.  The microclimate maps are using the SolarCal model, which was just officially accepted into the ASHRAE-55 Thermal Comfort Standard and is described in detail here:

http://escholarship.org/uc/item/89m1h2dg#page-1

Example files with the microclimate maps include the following:

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

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

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

I should note that the microclimate maps make a few assumptions about the occupant for the solarCal model (for example, the occupant is always seated and is always facing towards the south).  If you want to drill down into details of the solarcal model, you can use the Ladybug_Solar Adjusted Temperature component as seen in this file:

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

More info on the methods used by the microclimate maps can be found here:

http://www.grasshopper3d.com/group/ladybug/forum/topics/initial-doc...

-Chris

Hi Chris, Thank you very much for your reply.

Hi Chris,

I have just realised that my answer got cut after the first sentence.

I will look at the examples you mentioned.

In regards to the Solar Adjusted Temperature component, I guess it is appropriate to use it both for external and internal comfort evaluations given the paper used as a reference in the description of the component and that you also mentioned? Is it a matter of 'just' using the proper inputs depending on whether we are interested in external or internal comfort evaluation?

Many thanks again for your help.

Best,

Carmelo

Carmelo,

Yes, the Solar Adjusted Temperature component can be used both indoors and outdoors (as can the microclimate maps).  For the indoors, make sure that your baseTemperature is an MRT value and set _baseDryBulbOrMRT_ to False.  You should not have to plug in an values for _horizInfraredRad_ in this case.

-Chris

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