Question-and-Answer Resource for the Building Energy Modeling Community
Get started with the Help page
Ask Your Question

Create Variable Speed RTU issue.

asked 2021-01-19 17:01:26 -0600

Biraj's avatar

updated 2021-01-20 08:55:33 -0600

Hi there,

I used "Create Variable Speed RTU" in the form of Apply Measure and I got the message as shown in the screenshot (link below). I have tried to do this with constant fan system in all the zones as well as with no equipment assigned, in either case I got the same message. To be specific, I had initially applied "Add a PSZ-HP to each zone" and this had a DX heat pump system with constant volume fan and no reheat. When I tried to replace this system with "Create Variable Speed RTU" in all zones, I got the same message.

Here is the link to the screenshot: https://estesmcclure01-my.sharepoint....

I would appreciate any help on this.

Thank you, Biraj

edit retag flag offensive close merge delete

1 Answer

Sort by ยป oldest newest most voted

answered 2021-01-20 08:54:55 -0600

The lines under Standard Output: are errors that OpenStudio encounters when trying to translate your OSM into an EnergyPlus input file (IDF).

OpenStudio translation errors

These three lines say that an OS:SubSurface object (shade, window, etc.) named "Sub Surface 56" has more vertices or corners than EnergyPlus allows. Without seeing your model, I have two guesses as to what's causing this:

  • You have defined a shading group that contains many shade surfaces. To fix this, cut and paste some shade surfaces into new shading groups.
  • You have drawn a very complex subsurface with many vertices. To fix this, simplify the shape of the subsurface to have the same area with fewer vertices.

It is strange that applying this Create Variable Speed RTU measure that deals with HVAC is translating geometry. However, even if the measure wasn't doing this, you would very likely still encounter this translation issue when you simulated the OpenStudio model.

edit flag offensive delete link more

Your Answer

Please start posting anonymously - your entry will be published after you log in or create a new account.

Add Answer


Question Tools

1 follower


Asked: 2021-01-19 17:01:26 -0600

Seen: 100 times

Last updated: Jan 20 '21