TRNSYS Forum - Recent Topics https://trnsys.org/community/ TRNSYS Discussion Board en-US Mon, 20 Apr 2026 06:13:55 +0000 wpForo 60 Type786 https://trnsys.org/community/component-libraries-tess-libraries-transsolar-components-user-written-components/type786/ Fri, 17 Apr 2026 19:55:30 +0000 Hello,

I am using Type786 and I set Control Mode = 0 (Parameter #1) to operate the heat pump as an ON/OFF unit. However, when I run the simulation, I receive the following error message:

"14 INPUTS are required and 16 INPUTS were specified."

I understand the reason: when Control Mode = 0, Input #15 (heating mode supply air temperature setpoint) and Input #16 (cooling mode supply air temperature setpoint) are not needed. These two inputs are only relevant when Control Mode = 1 (variable speed operation). 

My question is: is there a way to disable or deactivate Input #15 and Input #16 when Control Mode = 0, without having to modify the source code or the ProForma file? I am looking for a standard, user-level solution.

 

]]> yalikara https://trnsys.org/community/component-libraries-tess-libraries-transsolar-components-user-written-components/type786/ Type786 - Different number of air flow rate steps for heating and cooling https://trnsys.org/community/standard-forum/type786-different-number-of-air-flow-rate-steps-for-heating-and-cooling/ Sun, 12 Apr 2026 18:41:03 +0000 Type786 requires the same number of air flow rate steps for both heating and cooling performance data files. I have manufacturer data (Goodman) with 4 flow rate steps for cooling, but for heating the table  provides only one flow rate.

What do you recommend?

  1. Use only the cooling rating flow rate (1160 CFM) for both modes (single step each)?

  2. Copy the single heating flow rate 4 times to match the 4 cooling steps?

Thanks.

]]> yalikara https://trnsys.org/community/standard-forum/type786-different-number-of-air-flow-rate-steps-for-heating-and-cooling/ Modeling a two-way valve https://trnsys.org/community/component-libraries-tess-libraries-transsolar-components-user-written-components/modeling-a-two-way-valve/ Thu, 09 Apr 2026 12:13:01 +0000 Hi,

I would like to model a heating circuit in a building, with a single-speed pump (type 114) and a valve that is connected to a PID-controller. The valve should modulate the flow rate in the circuit, based on the control signal from the PID-controller. What is the easiest way to model this? I have not found a valve type appropriate for this purpose. Is it best to use a valve+single-speed pump, or is it easier to use a variable-speed pump instead? If I use the single-speed pump, will the flow rate be affected by a valve, or will it always keep the same, constant flow rate?

Best regards,

Johan

]]> jolind https://trnsys.org/community/component-libraries-tess-libraries-transsolar-components-user-written-components/modeling-a-two-way-valve/ SketchUp to TRNBuild import issue https://trnsys.org/community/modeling-buildings-in-trnsys-trnsys3d-trnbuild-type-56/sketchup-to-trnbuild-import-issue/ Fri, 03 Apr 2026 14:26:04 +0000 Hello everyone,
I’m trying to model a simple zone using SketchUp and then import it into TRNBuild, but I’m running into an issue.
Here’s what I did:
-Created a simple parallelepiped geometry in SketchUp
-Exported the model as an *.idf file
-Imported the file into TRNBuild

After importing, the zone appears to exist, and I can see 9 walls listed (not 6). However, all the surface areas are showing as 0 m².
I’ve attached screenshots for reference.
Has anyone encountered this issue before or knows what might be causing it? Any help would be greatly appreciated!
Thank you in advance.

Mariem

]]> Mariem S https://trnsys.org/community/modeling-buildings-in-trnsys-trnsys3d-trnbuild-type-56/sketchup-to-trnbuild-import-issue/ Fortran Compiler https://trnsys.org/community/component-libraries-tess-libraries-transsolar-components-user-written-components/fortran-compiler/ Tue, 31 Mar 2026 16:33:12 +0000 Dear TRNSYS users,

I was using Intel Fortran (Ifort 2022) with Visual Studio 2019 for developing and debugging Types, and everything was fine. But I changed my computer and this solution is no longer available. 

As far as I know, there is no debugging options with Type Studio, and TRNSYS 18 is not compatible with the new Intel Fortran compiler (Ifx).

What is now the best solution to debug user written types ?

Regards

Philippe

]]> Papillon https://trnsys.org/community/component-libraries-tess-libraries-transsolar-components-user-written-components/fortran-compiler/ Window frame https://trnsys.org/community/modeling-buildings-in-trnsys-trnsys3d-trnbuild-type-56/window-frame/ Sun, 29 Mar 2026 00:47:52 +0000 Hi everyone,

What is the best way to model the window frame?

I remind these recommendation reported in manuals/slides, which appear to be contradictory:

  • It is better to model the window frame as a Wall and set FFRAME = 0.
  • the frame should be defined in TRNBuild (see slide attached)

Does “model the window frame as a Wall” mean that the frame has to be modelled in SketchUp/TRNSYS3D and then assigned the construction type Wall in TRNBuild, while the window frame fraction of the window, again in TRNBuild, should be set to 0?

If drawing the frame in SketchUp/TRNSYS3D is indeed necessary, what is the correct way to do it geometrically? I understand that it should obviously not be modelled as shown in the slide where the framed window is marked as “Doesn’t work in TRNSYS,” but I am unsure what the recommended workflow is.

 

I sincerely thank you in advance for your support

Warm Regards,

Silvia

]]> SilviaC https://trnsys.org/community/modeling-buildings-in-trnsys-trnsys3d-trnbuild-type-56/window-frame/