Inconsistent Thermal Asset Data

Rhino.Inside Revit
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1

Hi Rhino Inside Community,

I have a problem when deconstructing a compound structure (wall type) and its layers of materials, in order to extract thermal information for a Honeybee Energy model.

I have created the wall type using some standard Revit materials (gypsum board and steel stud frame).

Type
Type879Ă—1557 40.5 KB

When taking a look at the thermal asset information, we can see that the Gypsum board material has the following thermal data:

Thermal Asset
Thermal Asset1690Ă—1263 157 KB

  • Thermal conductivity = 0.65 W/(mK)
  • Specific heat = 0.84 J/(gC)
  • Density = 1,100kg/m3

However, when I use the Rhino.Inside.Revit Grasshopper components to extract this data, it changes:

GH
GH3571Ă—1066 222 KB

Just looking at the exterior layer of gypsum board here, we can see that the thermal conductivity has now changed to 6.996542.

The specific heat capacity has changed from 0.84 to 840, but this is probably just because it is reporting the specific heat capacity in J/(kgC) instead of J/(gC), which I can work with.

The density is unchanged, which is fantastic.

Does anyone know why the thermal conductivity data is changing during this process?

image
image1284Ă—1272 87.1 KB

The thermal conductivity output info card for the grasshopper component is saying that the thermal conductivity data is in “feet-kilograms per Kelvin-cubed second”… The other output info cards for specific heat capacity and density also include units mixing metric and imperial measurements…

Please let me know if you can help :slight_smile:

Cheers,

Anthony

2

Hi @AnthonySchneider,

The tooltip is wrong, the value is in %MODEL-UNITS%-kilograms per Kelvin-cubed second
Where MODEL-UNITS is meters if your Rhino model is in meters.

All length units or relative to length quantities are in Rhino model units in Grasshopper.

1 Like
3

Hi Kike, thanks for your help :slight_smile:

Cheers,

Anthony