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Hello together,

I am wondering how the shadow calculation in EnergyPlus exactly works. In detail, I would like to know which radiation components are taken into account in my simulation and which are not. I have a thermal zone that is shaded by a few detached shading objects, which are neighboring buildings.

Regarding radiation, I would differentiate between 1. direct solar radiation, 2. diffuse solar radiation, and 3. long-wave radiation (influencing the energy balance of the surfaces of my thermal zone). What I understood so far:

1. shading of direct solar radiation (sky)

2. is taken into account geometrically

3. shading of diffuse solar radiation (sky, ground)

4. only considered regarding the sky --> calculation of a modifier for the sky view factor

5. not considered for the ground(?)

6. shading of long-wave radiation:

7. coming from the sky --> yes, via an isotropic shading factor R_dome
8. coming from the ground --> no blocking

9. "The long-wave radiation from these obstructions is added to the long-wave radiation from the ground; in this calculation both obstructions and ground are assumed to be at the outside air temperature and to have an emissivity of 0.9." (EnergyPlus Engineering Reference)

10. what shading surfaces "(not) do":

11. using Full(InteriorAnd)ExteriorWithReflections in the Building object --> shading surfaces also reflect solar radiation onto the building, AND they shade diffuse solar radiation coming from the ground, not only from the sky (EnergyPlus Input Output Reference) (shading/blocking of long-wave radiation from the ground is still not considered?)
12. do shading objects emit and reflect long-wave radiation?

Is that correct? My questions are written in italics.

I appreciate any help!

Best, M.

Hello together,

I am wondering how the shadow calculation in EnergyPlus exactly works. In detail, I would like to know which radiation components are taken into account in my simulation and which are not. I have a thermal zone that is shaded by a few detached shading objects, which are neighboring buildings.

Regarding radiation, I would differentiate between 1. direct solar radiation, 2. diffuse solar radiation, and 3. long-wave radiation (influencing the energy balance of the surfaces of my thermal zone). What I understood so far:

Is that correct? My questions are written in italics.

I appreciate any help!

Best, M.

Hello together,

I am wondering how the shadow calculation in EnergyPlus exactly works. In detail, I would like to know which radiation components are taken into account in my simulation and which are not. I have a thermal zone that is shaded by a few detached shading objects, which are neighboring buildings.

Regarding radiation, I would differentiate between 1. direct solar radiation, 2. diffuse solar radiation, and 3. long-wave radiation (influencing the energy balance of the surfaces of my thermal zone). What I understood so far:

1.shading of direct solar radiation (sky)

• is taken into account geometrically

2.shading of diffuse solar radiation (sky, ground)

• only considered regarding the sky --> calculation of a modifier for the sky view factor

• not considered for the ground(?)

3.shading of long-wave radiation:

• coming from the sky --> yes, via an isotropic shading factor R_dome

• coming from the ground --> no blocking

• "The long-wave radiation from these obstructions is added to the long-wave radiation from the ground; in this calculation both obstructions and ground are assumed to be at the outside air temperature and to have an emissivity of 0.9." (EnergyPlus Engineering Reference)

4.what shading surfaces "(not) do":

• using Full(InteriorAnd)ExteriorWithReflections in the Building object --> shading surfaces also reflect solar radiation onto the building, AND they shade diffuse solar radiation coming from the ground, not only from the sky (EnergyPlus Input Output Reference) (shading/blocking of long-wave radiation from the ground is still not considered?)

• do shading objects emit and reflect long-wave radiation?

Is that correct? My questions are written in italics.

I appreciate any help!

Best, M.