Creating a sunshade for energy analysis

[sumedha2512]

Dear Revit users,
Hello...
I would like to know what is the best way to create a sunshade for a window?
Also, will it be possible for the 'sunshade' to behave as one, if I want to do an energy analysis in MEP?
Thanks!
Sumedha.

[jeffh]

The sunshade needs to be created form an object that can be recognized as a shading surface when running the analysis. Only walls, floors, and roofs are considered when calculating for shade surfaces. Your "sunshade" will somehow need to use these objects or they will NOT be analyzed as a shading surface.

[swalton240189]

I'm not sure about within Revit MEP but I know for GBXML export they can't be in place families either. They have to be normal floors, walls or roofs like Jeff said.

[Scott D Davis]

Once you get gbXML data into Ecotect, you can set the geometry to be a shading device. So at least in Ecotect, it doesn't matter what the objects were in Revit.

[cliff collins]

Perhaps these should be created as individual Roofs for shading analysis?

OR--

Would it be possible to create a generic model, with the "slats" and custom profiles
that are usually asscoiated with sunshdes, and then change the Family Type to Roof? or create it under the Roof category?
( I'm thinking of the louvered fins which some curtainwall mfgs. provide )

Would Green Building Studio then include them for analysis when exported to gbxml?

cheers......

[kyle.bernhardt]

Guys,
In 2010, it's pretty easy to understand what's output in gbXML, just look at the Analytical Surfaces view in the gbXML Export dialog. It's WYSIWYG for gbXML Export.

Jeff is correct here, there are no ways to get "custom" shading surfaces into gbXML without using the System Families.

You can always use a mix of gbXML and DXF to get everything over to a tool like Ecotect, but GBS is dependent on only gbXML so you'll have to get creative.

I do have to wonder, if you're using a Schematic Energy tool like GBS, why you need to model with that level of detail. The other assumptions in the analysis (Form, Orientation, HVAC Systems, Lighting Systems, Constructions, Usage Info, etc) are gonna move the needle way more than the difference between a big shade and a slated shade.

Cheers,
Kyle B

[aaronrumple]

Would it be possible to create a generic model, with the "slats" and custom profiles
that are usually asscoiated with sunshdes, and then change the Family Type to Roof? or create it under the Roof category?

Only in-place families can be built as system families (walls, floors, roofs, etc.) Families made through the family ditor cannot be set as sysem families. Since in-place families can't be instanced - it doesn't provide any advantage over just doing lots of small roofs.

[aaronrumple]

Guys,


I do have to wonder, if you're using a Schematic Energy tool like GBS, why you need to model with that level of detail. The other assumptions in the analysis (Form, Orientation, HVAC Systems, Lighting Systems, Constructions, Usage Info, etc) are gonna move the needle way more than the difference between a big shade and a slated shade.



..because when what your are analizing doesn't match the actual construction - then the client (and boss) don't trust the data. And you have no scientific data to support otherwise.

Besides - it might be nice tyo know the difference between a big shade and a small shade. Those little slats can be expensive. What's the ROI?

[kyle.bernhardt]

Aaron,
To be clear, I'm not questioning the need to know the difference between the two, just the relative importance of such a detail at the schematic stage of design.


..because when what your are analizing doesn't match the actual construction - then the client (and boss) don't trust the data. And you have no scientific data to support otherwise.

Agree that this is an area of challenge with many energy tools today, understanding what is contributing to the energy calculations those tools produce, and how critical one element is to the end value.

My point in asking this is that Green Building Studio is a schematic energy analysis tool, not a detailed energy analysis tool. Thus, it's best used to help make big decisions about the building where comparative results are valuable to drive design decisions (like orientation, macro-level constructions decisions, HVAC systems, Lighting Controls, etc.). If you're looking for dead-on accurate results that you can hang your hat on, then you want a detailed energy analysis tool (and a lot of time to learn and build a full blown energy model).


Besides - it might be nice tyo know the difference between a big shade and a small shade. Those little slats can be expensive. What's the ROI?

Totally agree, they are expensive. If that's the end goal, and you really want to articulate the ROI, then you need to do some detailed analysis on some typical instances of those slated shading devices. The sort of stuff you can do in Ecotect or IES.

Do some light calculations to determine the reduction of radiant heat gain through the shaded area, a study on the impact of natural light quality from the shading devices (glare, reflections, etc), evaluate the use of daylighting controls based upon the natural light...more than just energy.

As for Revit's need to support these more detailed analysis needs, you are not the first to articulate those needs, and we in the Product Management team understand how important these types of problems are to folks like you trying to get buy-in from the "client (and boss)". It's something we're investigating for improvements down the road.

Cheers,
Kyle B

[aaronrumple]

Aaron,
To be clear, I'm not questioning the need to know the difference between the two, just the relative importance of such a detail at the schematic stage of design.

My point in asking this is that Green Building Studio is a schematic energy analysis tool, not a detailed energy analysis tool.

I agree with your points. My comments were based more on the criticizm I hear coming from owners and management. When A doesn't match B - they get confused. So I would need to still show the sun screen and then fake it with other objects not shown to the client.

I think Revit has also changed the level of detail expected at the end of schematics.

[kyle.bernhardt]

I think Revit has also changed the level of detail expected at the end of schematics.

:p. So much so that the the underlying Analysis Engines can't handle that level of detail without waving the white flag, which is one of the underlying reasons why we have the the current behavior (DOE 2.2 had a limit of 1024 shading surfaces if I recall correctly, we fixed that recently).

Cheers,
Kyle B