OpenStudio SketchUp EnergyPlus - 기타 팁 2021년 12월 12일

27. Building Energy Modeling in OpenStudio - Troubleshooting 4

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In this series of episodes, we discuss some common simulation warnings and errors found in the EnergyPlus eplusout.err file.  We will discuss these errors, and show common strategies to resolve them.  Errors in this episode: 1. CalculateZoneVolume: The Zone="THERMAL ZONE 1" is not fully enclosed. To be fully enclosed, each edge of a surface must also be an edge on one other surface. 2. The surface "SURFACE 10" has an edge that is either not an edge on another surface or is an edge on three or more surfaces:

Transcript:

Okay, we are back here for another episode of troubleshooting the errors. We are looking at the eplusout.err file. 
The next warning that we get is CalculateZoneVolume: The Zone="THERMAL ZONE 1" is not fully enclosed. To be fully enclosed, each edge of a surface must also be an edge on one other surface.
Then it says The zone volume was calculated using the opposite wall area times the distance between them method.
So, that is the first error. We are going to look atthis next one in a minute. These are two related.
Let us talk about this calculate Zone volume error. First we will go take a look at the model.
One of the things that we need to note is this model has a single Thermal Zone. Even though I have all of these different spaces, when this gets passed to EnergyPlus it becomes one big blob.
It is a combination of all of the spaces. It is an average of all of these different spaces.
If we take a look at this rendered by Thermal Zone, you can see it is just one Thermal Zone. There are no other colors.
So, this whole thing gets passed to EnergyPlus as a single piece of geometry. A single zone that would be controlled by a single thermostat.
But, it is complicated. There is complicated geometry. With this error "calculate Zone volume" EnergyPlus is saying the geometry is not fully enclosed.
EnergyPlus is saying there is a piece missing somewhere. For example, there is a hole or something in your geometry.
EnergyPlus is saying this is not fully enclosed. There is a hole somewhere, so it can not calculate the volume based on all of the surfaces.
So for example EnergyPlus will calculate the distance between, say, this wall here and this wall here and it multiplies it by the area of this wall.
EnergyPlus is assuming that this is basically just a rectangular Thermal Zone. But it is not. Therefore, EnergyPlus tends to make very big mistakes on this.
There are two ways to solve this problem. You can figure out where the hole is and try to patch it up.
But, sometimes that is not successful because the holes can be very small. Or, there could just be some mismatch in your lines that are connecting the spaces.
The other solution is to hard size the volume and the floor area. Basically, you would manually calculate what the floor area is.
Then, you would enter it in here; in the Thermal Zone in the Open studio inspector.
Then, you would calculate the volume and then hard size that right here.
How would you do that? You can have SketchUp do it for you! We will just open up another instance of SketchUp.
We will copy all of this. Click Control-A to select all. Control-C and copy this. Click Control-V to paste it in here.
Now we have our model pasted into another instance of SketchUp. Click Control-A to select everything and then right click and explode the whole thing.
That destroys all of our spaces that we created. It just makes the model dumb. All of these surfaces are at the very top level. It is all one big mixture of surfaces.
We will do a side view...and change the perspective...then go through here and delete all of the walls.
Delete all of the walls. This gets kind of tricky, especially if you have Windows...
I have most of it deleted...then you can open up the default tray, entity info.
Entity info. If you click on any one of these surfaces, SketchUp will show you what the area is.
You could go through and and add all of these up. Alternatively, you could have SketchUp calculate that for you.
We will just hide this for now. Click hide. Then, do a top-down view of this. Now we can just delete all of these floors.
Now it is one big floor. Then, if you just add one line here, it should connect everything up into a single surface.
Now, if you click on that surface, that will give you the total floor area. Right here.
12,435. Then, you can go into your model and hard size the floor area. Click hard size and then put in 12,435.
You can do the same thing for volume...if we do unhide all...unhide all.
If you unhide everything...you would still need to go through and delete these windows and stuff...
So, assume we deleted all the windows; then you start connecting this together into one piece of geometry.
You may have to delete all of these ceilings too. Once you have the whole thing patched up into one big piece of geometry...
You should be able to click on it and SketchUp will tell you what that volume is.
I will do a sample here....just delete most of this here...just focus on this here...well this is kind of an odd shape...
I will just show you something real quick. I will just draw a rectangle and then push-pull it.
If you click on the surface SketchUp will tell you the area. Now, select the whole thing, right click, and do a "make group".
Now, SketchUp will tell you what the volume is right here.
That is basically what I did with this is. I removed all the walls, the floors, and the ceilings, and I reconnected everything up and so it was one continuous, hollow piece of geometry.
Then I had a SketchUp calculate the volume. So that is one way for solving this calculate Zone volume error.
That is basically the way you solve it if you have complex geometry.
But, we will go into this a little bit farther because this error is actually connected with this other error.
This other error, the next error, says The surface "SURFACE 10" has an edge that is either not an edge on another surface or is an edge on three or more surfaces:.
Then, it tells you what the vertex start and end point is for that edge.
Let us go back to our model...and we can go to the inspector tool...and we can look at surfaces.
In this instance we are looking at surface 10. If we look at surface 10...
Sometimes it is difficult to find these, so we can put it in x-ray mode.
If you still do not see it, you can go to edit face, select all connected. Then it is a lot more apparent where that surface is.
It is going to be on this volume here. Surface 10 is actually this surface right here. You can click on it so that is surface 10.
The error is saying that it has an edge on another surface or is an edge on three or more surfaces.
I would suspect it is probably talking about this Edge right here. It is connected to this space, it is connected to this space, it is connected to this space and it is connected to this space.
So, it is sharing an edge on three or more surfaces. What is the reason for this error?
OpenStudio/EnergyPlus does not recognize this wall as an interior wall. It got exported to EnergyPlus as an exterior wall.
So, EnergyPlus is saying "why is this Edge surrounded by other surfaces, it should be on the outside like this Edge".
So, how do you solve that error and why are we having that problem?
It is because this whole thing is considered a single Thermal Zone. It is getting imported to EnergyPlus is a single Thermal Zone.
We could separate these out into their own individual thermal zones.
You can do that by changing the attributes on these spaces. Go to the set attributes and create a new Thermal Zone.
Another solution would be to try doing surface matching. Surface matching tells OpenStudio/EnergyPlus which surfaces are going to be exterior surfaces and which surfaces are going to be interior surfaces.
To do that, go to the surface matching tool and select intersect in entire model first.
Intersecting will catch any missing surfaces that should be matched.
For example, when you do surface matching, you want to make sure that this surface here is the same geometry and area as the opposing surface (this side here).
Surface matching is going to match those surfaces together and it is going to say this surface here is going to be sharing heat transfer with this surface here.
That way, EnergyPlus will know that it is an interior wall.
Let us do Intersect in Entire Model. It says that it is irreversible. You want to make sure that you are okay with that. Make sure to save your model beforehand.
Click ok. now it has intersected all the surfaces. Then you can click Match in Entire Model. Make sure to save it to have a backup. Just in case something goes wrong.
Click ok. It is done. How do we know that it matched? Go to render by boundary condition. We will go back to x-ray mode.
You can see that all of these interior walls are green now. They used to be blue.
Now, for example, this wall right here, the surface has been matched to the other surface on the other side.
Now EnergyPlus knows that heat transfer is occurring between those two surfaces. It knows that those surfaces are interior and so you will no longer have that edge error...here.
The error that says the edge is either not anedge  on another surface or it's sharing an edge on three or more surfaces.
Now, let us go ahead and save our model. We will save it as version four...
We can open up our model...let us see here...and we will now run the simulation and see if we get that error...
The model has run successfully. Let us open up that error file. We are going to have to open up the newer version of it that we saved.
Go to the Run folder...eplusout.err...it is still telling us that this Thermal Zone one is not fully enclosed. There may still be some geometry errors.
So, it may be good that we hard sized that volume and area.
It also says: The surface "Surface 2" has an edge that was used 6 times...
so, apparently some of these interior zones are are causing errors...
we should just separate all of these spaces into their own Thermal Zone. How would you do that?
There is a simple user script in SketchUp that you can use.
First, we will go to the thermal zones tab in OpenStudio. We will delete this Thermal Zone. Save it. Then, reload it in SketchUp.
If we go to "render by Thermal Zone", you can see that there are no thermal zones assigned. We do not have any of these spaces assigned to a Thermal Zone.
We can go to the extensions, OpenStudio user scripts, alter or add model elements, add new Thermal Zone for spaces with no Thermal Zone. I cover this in one of my other videos.
Now that we are rendered by Thermal Zone you can see that each one of these spaces now has its own Thermal Zone.
Save the model. Go ahead and revert to the saved in OpenStudio.
You can see that all these thermal zones were created.  Now we will run the model.
The model was run successfully. If we go back to our error file, we will reload it and you can see that a lot of those errors have been resolved.
It is still calculating a Zone volume for thermal zone six. It is saying Thermal Zone 6 is not fully enclosed.
Again, we would have find that thermal zone six. Browse for it in the inspector tool...
Here we go. This was thermal zone six. Thermal Zone six is is obviously having some issues.
It could be a very small Gap in the wall. Or really anything. Like I said, you can hard size these.
You can calculate the floor area and space volume. You can calculate the floor area...so 1682 square feet.
If we render by Thermal Zone...we can say that the floor area is 1682 square feet. And, again, you can calculate the volume like I said before using SketchUp...
You can hard size the volume in there. So, that is how you solve the calculate volume error.
Then...the next error...surface 25 has an edge that was used only once. It is not an edge on another surface...
Let us take a look at surface 25...we can click surfaces, scroll down to 25...and...find out where that is...
We will select all connected. It looks like...yeah surface 25 is actually associated with this Thermal Zone.  The one with problems.
So, surface 25...here we go...it is this surface here.  It is saying it is not an edge on another surface.
It is not an edge on another surface.
We go back to 25...you can see that this surface 25 is an exterior surface. That is true. It is not an edge on another surface.
It looks like we found our gap in this in this volume. If we fix this hole that may correct the The Zone volume for that space. It may fix those errors.
Also, with thermal zones seven, it is not possible to calculate volume.
Again we might have one of those those holes in our space. So we will go ahead and try to resolve those errors.
That is enough for today. That is how you solve those two errors.
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