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CTF calculation convergence problem for Construction

asked 2022-09-11 03:24:07 -0500

updated 2022-09-11 07:48:09 -0500

Hello to all friends This error has been observed in my simulation for a thermal area:

Severe  ** CTF calculation convergence problem for Construction="FLOORCONSTRUCTION(1)".
   **   ~~~   ** ...with Materials (outside layer to inside)
   **   ~~~   ** (outside)="FLOORMATERIAL FOR CONSTRUCTION(1)(2)"
   **   ~~~   ** The Construction report will be produced. This will show more details on Constructions and their materials.
   **   ~~~   ** Attempts will be made to complete the CTF process but the report may be incomplete.
   **   ~~~   ** Constructs reported after this construction may appear to have all 0 CTFs.
   **   ~~~   ** The potential causes of this problem are related to the input for the construction
   **   ~~~   ** listed in the severe error above.  The CTF calculate routine is unable to come up
   **   ~~~   ** with a series of CTF terms that have a reasonable time step and this indicates an
   **   ~~~   ** error.  Check the definition of this construction and the materials that make up


    **   ~~~   ** the this->  Very thin, highly conductive materials may cause problems.

   **   ~~~   ** This may be avoided by ignoring the presence of those materials since they probably
   **   ~~~   ** do not effect the heat transfer characteristics of the this->  Highly
   **   ~~~   ** conductive or highly resistive layers that are alternated with high mass layers
   **   ~~~   ** may also result in problems.  After confirming that the input is correct and
   **   ~~~   ** realistic, the user should contact the EnergyPlus support team.

Next, I will put the osm file related to the surface, thank you for your guidance

OS:Construction,
  {d66f158f-dd77-48f5-8193-029846718bd8}, !- Handle
  FloorConstruction(1),                   !- Name
  ,                                       !- Surface Rendering Name
  {13b6c17b-2ace-4e39-a0ab-8fe4ebd9ed8a}; !- Layer 1

OS:Material,
  {13b6c17b-2ace-4e39-a0ab-8fe4ebd9ed8a}, !- Handle
  FloorMaterial For Construction(1)(2),   !- Name
  MediumSmooth,                           !- Roughness
  0.87559958999589,                       !- Thickness {m}
  0.1,                                    !- Conductivity {W/m-K}
  1920.0018527311,                        !- Density {kg/m3}
  790.4674978944,                         !- Specific Heat {J/kg-K}
  ,                                       !- Thermal Absorptance
  0,                                      !- Solar Absorptance
  0;                                      !- Visible Absorptance

OS:Surface,
  {1bda4813-6706-4bbb-8792-9e13cd32a8cd}, !- Handle
  Space(2)Floor(1),                       !- Name
  Floor,                                  !- Surface Type
  {d66f158f-dd77-48f5-8193-029846718bd8}, !- Construction Name
  {e6cc311b-835e-48b6-82a8-bab0a2a6ee29}, !- Space Name
  Ground,                                 !- Outside Boundary Condition
  ,                                       !- Outside Boundary Condition Object
  NoSun,                                  !- Sun Exposure
  NoWind,                                 !- Wind Exposure
      ,                                       !- View Factor to Ground
      ,                                       !- Number of Vertices
      7.49581831120207, 4.56265123368215, 0,  !- X,Y,Z Vertex 1 {m}
      1.49581811920207, 4.56265123368215, 0,  !- X,Y,Z Vertex 2 {m}

  1.49581811920207, 1.56265113768214, 0,  !- X,Y,Z Vertex 3 {m}
  7.49581831120207, 1.56265113768214, 0;  !- X,Y,Z Vertex 4 {m}
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answered 2022-09-11 04:48:47 -0500

CTF calculations find problems when dealing with large massive layers, as it is your case. I would recomend to reduce the material thickness and properly adjust the ground temperature according to your case.

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thank you I assumed the ground temperature to be 18C for the whole year

Masoud's avatar Masoud  ( 2022-09-11 05:04:21 -0500 )edit

Thank you for your advice, I followed your instructions and my problem was solved

Masoud's avatar Masoud  ( 2022-09-11 06:40:44 -0500 )edit

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Asked: 2022-09-11 03:24:07 -0500

Seen: 82 times

Last updated: Sep 11