no effect of local shade or projection added in glazing

[alisyed]

Hi.
I am using ies 6.2. I am running compliance for a school model and its overheating. I first tried using local shades as I construction but no effect on %age heating of concerned rooms, and then I used local shading within glazed construction as projections.
For projection I entered window with, height & overhang projection and overhang offset, but still no change in %age overheating of the rooms.


Thanks
Ail

[PCully]

Hi,

Not sure if you are using SBEM or ApacheSim method.

If ApacheSim then make sure you recalculate your Suncast solar shading results before you re-run the simulations so that the effect of any changes to shading can be taken into account.

If SBEM then Local Shading options in the CDB are not taken into account and you should represent this as External or Internal shading on the Glazing construction.

Also if you are running ApacheSim you can check the results in Vista and confirm more accurately if the Solar Gains have changed as a results of the shading device.

Phil

[alisyed]

Hi.
yah sorry i did not mentioned that i am runing sbem calcs.
i added it as local shading in glazing construction. first i tried as normal local shade by constructing it above window.
then i went in glazing construction and clicked local shade there but still no effect.

thanks
ali

[PCully]

Thanks for clarifying, as always with SBEM you are a little restricted.

VE-SBEM won't recognise the effects of shading objects drawn in the model (this is for the VE-Pro modules and in terms of Compliance it affects ApacheSim/SunCast Solar Shading results).

VE-SBEM doesn't use the Local Shading devices defined in CDB, you need to represent the shading device as either External or Internal Shading device in CDB to get the benefit in your model.

Phil

[alisyed]

Hi Phil.
In glazing construction there are three options for shading devices.
1: Internal
2: External
3: Local.
If I am not wrong what I can understand is that among these three options in SBEM calculation I can only take benefit of internal and external devices. Projections (local shade) option will not work with SBEM.
Now if i consider louver and put profile continous. Put 0 for incident radiations, nigh time resistance. Alow it to calculate both diffuse. For transmission factor if I take 1 for 0° to 60° and 0.8 for 75° and 0.2 for 90°.
Will IES consider it as local shade.



thanks
ali

[jm2000]

I have a shade to assign that is along a wall that runs at an angle when looked at in plan, so the overhang is not a constant projection. i.e starts off at zero projection as the wall runs at an angle then has about a constant 1 m overhang once the wall runs parallel to the edge of the overhang . hope that makes sense!

Question is when running apache-SBEM, how do I apply it to a window as a "local shade" as the overhang isn't a constant width and it runs over areas where there is no window too?

p.s. I have ran suncast after removing and adding the shade.

HOPE YOU CAN HELP.

[PCully]

Hi John,

For SBEM there is no need to run SunCast as it will only be used in an Apache simulation. It's quite important to understand the differences here, Apache is dynamic so can use the simulation weather file hourly data in conjunction with the shading file from SunCast to take into account the self shading of the building, any additional shading surfaces you have drawn and solar tracking within the building more accurately.

SBEM can't get close to those details and so all you are doing with the simple shading options in the Construction is to alter the performance properties of the window to take into account the effects of whatever shading devices you have through means of a simple approach where you describe the effectiveness of the device as a shading coefficient.

So to answer your question you have to make a judgement on your shading device effectiveness at different points on your building and if it significantly differs then you can create different window constructions with the same pane properties but varying shading device effectiveness and assign this to the different parts of the façade.

If you want to get a good result and save some effort - use ApacheSim DSM!

Phil

[jm2000]

Hi Phil,

When you say use apache sim DSM, dos this mean running the 'Apache -SBEM' , that can be selected at the top of the screen on the drop down, instead or running a simple SBEM?

Also is there anyway to take into account a tall building which is providing shading to large windows that are currently failing the Criterion 3 test?

Thanks

John

[jm2000]

Always helps to check the suncast box under 'set buildings & system data' meanign it considers the shading !