Unmet Hours

Open Studio 1.5 - Zone has no surfaces

asked 2014-11-14 08:56:12 -0500

ptruong
261 ●4

updated 2015-07-10 09:04:36 -0500

__AmirRoth__

4436 ●5 ●17 http://bleedinggreenna...

Hello, When running my simulation, I get this error:

Program Version,EnergyPlus-Windows-64 8.1.0.009, YMD=2014.11.14 09:02,IDD_Version 8.1.0.009
   ************* Beginning Zone Sizing Calculations
   ** Severe  ** GetSurfaceData: Zone has no surfaces, Zone=THERMAL ZONE 1
   **  Fatal  ** GetSurfaceData: Errors discovered, program terminates.

The geometry is a test model, a very simple one room zone created in SketchUp 2014. I projected all loose geometry, did surface matching (though not sure if that is needed for just one space), assigned space attributes including creating a new thermal zone, and ran it with ideal air loads. Everything looked fine in the Open Studio Facilities tab, so I am not sure why the surfaces are not carried over into the idf.

I had previously added a low temp radiant panel to the zone, which also resulted in an error saying that the surfaces and corresponding flow fractions were not defined within the ZoneHVAC:LowTemperatureRadiant:SurfaceGroup object. I am not sure if the first error (no surfaces in the model) caused the second (no surfaces available for surfacegroup definition), or if the second error somehow triggered something in the model that deleted all my surfaces from the idf. With the SketchUp app open in the background, I tried to create several more simple one-zone models with ideal air systems (no radiant panel), and kept getting the same no surfaces error.

However, when I finally closed out of the SketchUp app, and created a whole new model, opened up OpenStudio and ran it, everything was fine. But when I try the radiant panel again, I get the same second error from before.

answered 2014-11-14 09:05:31 -0500

David Goldwasser

20295 ●94 ●14 http://www.openstudio.net/

updated 2014-11-16 00:14:45 -0500

In the facility tab sort by zone and see if you have a zone without any spaces associated with it. I expect that your space and zone are not connected or you have an extra orphan zone.

Look at Thermal Zone 14 in the image below. Notice there is no arrow to the left of it. That means it can't be expanded because there are no spaces under it. It would fail in E+ because the zone doesn't have any geometry.

Now look at the "Unassigned Thermal Zone" heading. When that is red it indicates that one or more spaces in the model doesn't have a thermal zone assigned to it. As a result when you run a simulation that space (geometry and internal loads) wont' be part of your simulation.

image description

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Comments

I would like to share that I'm getting the same error from OS 1.5.2/SU 2014 despite assigning a thermal zone to a space to clear the red "Unassigned Thermal Zone" as shown by David. Also, when I checked in SU inspector, the no. of spaces is more than the thermal zones indicating unassigned spaces. I used the measure available in SU to create and assign thermal zones to spaces without thermal zones but nothing happens.The error keeps on appearing despite manually creating a thermal zone and assigning a space to it. I re-installed OS but the error still appears.

dannyllim ( 2014-11-21 07:07:42 -0500 )edit

@dannyllim, the only other reason I can see that happening is if you have a space assigned to a zone, but the space doesn't have any surfaces. Look at the specific zone mentioned in the error, then confirm by using the facility tab again not only that there is a space, but expand the space and see if it has any surfaces. When you first expand a space you will see folders for different surface types (Roof/Ceilings, Walls, Floors). You should have surfaces under all of those, but your error would imply that none of them have surfaces.

David Goldwasser ( 2014-11-21 15:04:46 -0500 )edit

Aha..I have an unassigned space but the space has no surfaces. How can I delete the space?

evan ( 2015-08-07 04:41:18 -0500 )edit

Open the OSM in the SketchUp plugin. Select the space you want to delete in the OpenStudio Inspector, as it may be hard to select in the 3d view. Then click on the edit menu of the main SketchUp window and choose delete. You can't just hit the delete key, keyboard shortcuts don't work while you the OpenStudio inspector is the active frame. You need to first go to the SketchUp window so it is active, but if you just click in the background space of the model you will loose your selection.

David Goldwasser ( 2015-08-07 14:34:53 -0500 )edit

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