QUESTION:
What determines whether I should use a ceiling object or roof object element in my zones for a thermal model ?
ANSWER:
Whether you use a roof or ceiling object depends on the size (mainly volume) of your roof, what sort of material properties you have to use and how close these are to the situation you are modelling.
Generally speaking if you have a large roof on your building and it has a considerable volume, then it would be best to model it and get ECOTECT to work out it's thermal performance.
You may also find it useful to examine the amount of heat gains/losses through your roof, and again this would require you to model it as a separate zone, in order to look at it's thermal contribution separately.
Also, with regard to materials, if your material definition considered the effect of a large volume of air that made up your roof as well as the ceiling construction at the bottom and the tile or metal roof cladding at the top, then there would be no real need to model the roof as a separate zone as all the thermal characteristics are determined by the material assignment -- you could just use the one object (shown in thicker yellow in the image below).
On the other hand if all you have is the material properties for the roof tiles and that of the ceiling, then you should really model the roof as a separate zone applying these to the top and bottom objects etc.
So that you can get a better feel for how to apply the varies material and element definitions in both cases, you can download the simple example shown below.
Ceiling from zone
In the purpose ogf thermal analysis
Creating a zone-object, creates a ceiling object from the extruded floor,
I have extended the walls to a cutting pane to accommodate an inclined roof higher.
The ceiling does not follow. In this case, the ceiling and the roof are the same construction.
1- Is there any easy way to get my ceiling adjusted up to the cutting pane?
2- do I have to draw them again?
3- From the discussion above, i have tried and find a ZONE has to have a ceiling, to get a volume.
And it seems natural for me to interprete a roof as the interface to the climate(outside).
In the case of a missing roof, is the ceiling interacting with the outside ( in the thermal calculations of Ecotect)?
4- when ceiling and roof are the same construction (roof with no air volume)
can I ignore the roof and give ceiling "roof"-properties?
Xav
Sustainable Design
Ceiling object
Xav,
1.2. When you create - extrude - a zone, your ceiling element is automatically defined as "Child" of the floor element. it is sorta locked in place so that wherever you move the floor, its ceiling follow.
If you want to "free" your ceiling, you have to "unlink" it (Crtl + u)from its parent.
in some instance, i delete the created ceiling and re-create one. It sometimes is the fastedt way to get what you are after.
3. Yes, the ceiling is interacting with the outside.
4. Yes, ceiling and roof elements are quite similar in fact, aside from the volume of air intrinsic to the roof element. You can assign roof properties to ceiling elements.
Best,
Olivier