IES-VE User Forum

hey CP,

I have a question again.

I made my top layer to be a internal room, hence the floor of the area I inserted a hole in it.

However when I wanted to find my roof surface temperature of the solid layer just below this internal room, it does not reflect any values. I believe it is due to the "hole" that I created and hence no surface temperature recorded.

However, if I removed the hole, this will affect the internal room that I am trying to create. any solution to this?

I have to be honest and say that I'm getting a bit confused about exactly what you are trying to achieve here.

If you want a surface temperature, you need a surface to interrogate. Trying to find out the surface temperature of a hole makes no physical sense so I fear you're not going to have much success.

I would suggest you try to interrogate the room temperature of the zone instead since it sounds like you are essentially after the air temperature.

hi CP,

Yeah I made a mistake in the modelling. The top layer is my internal room, follow by a solid layer call ROOF, then the last layer call CEILING.

The internal room is actually to find the air temperature in this zone, whereas the roof is modelled as the roof of the building with another layer call ceiling as the ceiling of the building.

I am trying to find the actual surface temperature of the roof and ceiling. But I am not sure whether to take the "ceiling/top" or "floor/bottom" surface temperature of the ROOF and CEILING zone. Any idea to this?

Hiya

Why is your internal room on top of your roof? Shouldn't the internal room be under the ceiling?

Here's how I would set this up in section view:

External air above (not a modelled zone)
-------------------------------------------------- surface 1 (glass as a hole)
Dummy zone
-------------------------------------------------- surface 2
Roof zone
-------------------------------------------------- surface 3
Ceiling zone
-------------------------------------------------- surface 4



Internal room zone



-------------------------------------------------- surface 5

Each of the zones have a thickness and surfaces 2, 3 and 4 will be seen as "Internal Floor/Ceiling" within the model with surface 5 seen as "Ground/Exposed Floor".

For example, surface 2 should have the layered construction of the roof assigned to it to equal the thickness of that zone as you have defined it before it hits the ceiling. Whereas surface 4 for example would probably only have a thin plasterboard construction assigned since this is the last later under the ceiling construction.

In the above case, you would interrogate the floor of the dummy zone to get the external roof temperature (surface 2 from above). To get the internal room ceiling temperature you would interrogate the ceiling of the Internal room zone (surface 4 from below).

Remember, within vista you will get a different temperature for surfaces depending on whether you interrogate them from above or below.

hi CP,

I got what you meant now. Thanks for the clarification.

I have some issues with the mircoflo and I hope u can assist me in that. I did posted in a thread under my name but currently still waiting for reply.

My problem is this:

After I import boundary layer, if I were to check the box for opening flow,i would have a flow imbalance. Hence I proceed without the opening flow condition in mircoflo.

After I am done simulating, how would I know which boxes to check on to know the air temperature and surface temperature of the model? Do I check all the boxes in the x,y,z scale? or do I click on the surface temp icon display display setting at the top?

Also,how can I obtain numerical figures on the model itself by clicking on it? any suggestions?

Sorry, I don't use Microflow.

On the odd occasion I need to dip my toes into the world of CFD I tend to use Flovent or CFX preferably with an expert on the end of a phone.

hi CP,

Thanks a lot for your assistance. I am almost done with project with the exception of the modelling in CFD.

Just cant seem to understand how the CFD works in mircoflo and because I am under student version, the admins refuses to assist me as student version don't cover support.. blah...

Here's how I would set this up in section view:

External air above (not a modelled zone)
-------------------------------------------------- surface 1 (glass as a hole)
Dummy zone
-------------------------------------------------- surface 2
Roof zone
-------------------------------------------------- surface 3
Ceiling zone
-------------------------------------------------- surface 4



Internal room zone



-------------------------------------------------- surface 5

Each of the zones have a thickness and surfaces 2, 3 and 4 will be seen as "Internal Floor/Ceiling" within the model with surface 5 seen as "Ground/Exposed Floor".

For example, surface 2 should have the layered construction of the roof assigned to it to equal the thickness of that zone as you have defined it before it hits the ceiling. Whereas surface 4 for example would probably only have a thin plasterboard construction assigned since this is the last later under the ceiling construction.

Hi CP,

I like to clarify on the setting which you mentioned.

My intention for the whole roof slab is 10mm plaster + 140mm concrete. To divide it, will be 10mm plaster + 70mm concrete for ceiling and 70mm concrete for roof layer.

So like you mentioned, surface 4 should be the plasterboard instead of the construction of the ceiling? So I will set it as 10mm plaster for this?

Surface 3 should be 70mm concrete since it is part of the ceiling construction? Whereas surface 2 is 70mm concrete to act as the roof layer?

How should I define surface 2,3,4? Do I set the internal ceiling of the internal room space as surface 4? internal ceiling zone as surface 3? and internal ceiling of roof layer as surface 2?

Please kindly advice. Thanks! I have also posted another thread on abnormal surface temperature and like to seek your help on that.

I believe the key is due to the sky light. when I remove the skylight in place of a 5cm concrete, the temperature gives a more practical answer.

Putting a sky light gives me abnormal temperature of up to 60+ degree which is 30 degree more than ambient air

Hello tkc

Perhaps a clearer diagram would be as below. Remember that you can only create and assign constructions; the corresponding 2 surfaces will simply be dependent on whatever the outer and inner layers of those constructions are:

External air above (not a modelled zone)

-------------------------------------------------- construction 1 (upper surface)
Construction 1, glass as hole
-------------------------------------------------- construction 1 (lower surface)

Dummy zone

-------------------------------------------------- upper surface of concrete
Construction 2, 70mm concrete?
-------------------------------------------------- lower surface of concrete

Roof void zone

-------------------------------------------------- upper surface of concrete
Construction 3, 70mm concrete?
-------------------------------------------------- lower surface of concrete

Ceiling void zone

-------------------------------------------------- upper surface of plaster
Construction 4, 10mm plaster
-------------------------------------------------- lower surface of plaster

Internal room zone

-------------------------------------------------- construction 5 (ground construction)