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

How to create "Sizing:Zone" for HVAC system

asked 2016-05-23 09:00:27 -0600

Muhammad gravatar image

updated 2017-05-08 15:44:16 -0600

I'm currently facing some problems in my simulation where I received a Fatal Error while running the simulation. I'm trying to fix the error as below:

** Severe  ** For autosizing of ZoneHVAC:TerminalUnit:VariableRefrigerantFlow VRF ZONE TERMINAL, a zone sizing run must be done.
**   ~~~   ** No "Sizing:Zone" objects were entered.
**  Fatal  ** Program terminates due to previously shown condition(s).

Any help in resolving this is highly appreciated.

edit retag flag offensive close merge delete


Please tag your questions with the software you're using (EnergyPlus here I guess)

Julien Marrec gravatar imageJulien Marrec ( 2016-05-23 11:28:09 -0600 )edit

Noted with thanks. You're correct, EnergyPlus. I've tagged it in the edit.

Muhammad gravatar imageMuhammad ( 2016-05-25 01:02:13 -0600 )edit

1 Answer

Sort by ยป oldest newest most voted

answered 2016-05-24 08:24:04 -0600

updated 2016-05-25 07:35:04 -0600

Autosizing requires input for operating conditions. Sizing:Zone objects are required and Sizing:System objects will be required to size air loop equipment. The best way to tell which example files have a specific object is to look at the ExampleFiles-ObjectsLink.html file.

To autosize your model, turn on the appropriate Do * Sizing Calculation input by entering Yes. Each of these fields will also require a Sizing:Zone, Sizing:System, or Sizing:Plant object, respectively. If you are using ZoneHVAC equipment (baseboard, PTAC, etc.) you will need to add the Sizing:Zone object. If you are using AirloopHVAC you will need both the Sizing:Zone and Sizing:System objects. If you have a plant loop, all three sizing objects are needed. Look at the InputOutputReference document for a description of these objects.

  Yes,                     !- Do Zone Sizing Calculation
  Yes,                     !- Do System Sizing Calculation
  Yes,                     !- Do Plant Sizing Calculation
  Yes,                     !- Run Simulation for Sizing Periods
  Yes;                     !- Run Simulation for Weather File Run Periods

Then add the appropriate sizing object. For example, for zone sizing, use a Sizing:Zone object:

  SPACE1-1,                !- Zone or ZoneList Name
  SupplyAirTemperature,    !- Zone Cooling Design Supply Air Temperature Input Method
  14.,                     !- Zone Cooling Design Supply Air Temperature {C}
  ,                        !- Zone Cooling Design Supply Air Temperature Difference {deltaC}
  SupplyAirTemperature,    !- Zone Heating Design Supply Air Temperature Input Method
  50.,                     !- Zone Heating Design Supply Air Temperature {C}
  ,                        !- Zone Heating Design Supply Air Temperature Difference {deltaC}
  0.009,                   !- Zone Cooling Design Supply Air Humidity Ratio {kgWater/kgDryAir}
  0.004,                   !- Zone Heating Design Supply Air Humidity Ratio {kgWater/kgDryAir}
  SZ DSOA SPACE1-1,        !- Design Specification Outdoor Air Object Name
  0.0,                     !- Zone Heating Sizing Factor
  0.0,                     !- Zone Cooling Sizing Factor
  DesignDayWithLimit,      !- Cooling Design Air Flow Method
  ,                        !- Cooling Design Air Flow Rate {m3/s}
  ,                        !- Cooling Minimum Air Flow per Zone Floor Area {m3/s-m2}
  ,                        !- Cooling Minimum Air Flow {m3/s}
  ,                        !- Cooling Minimum Air Flow Fraction
  DesignDay,               !- Heating Design Air Flow Method
  ,                        !- Heating Design Air Flow Rate {m3/s}
  ,                        !- Heating Maximum Air Flow per Zone Floor Area {m3/s-m2}
  ,                        !- Heating Maximum Air Flow {m3/s}
  ;                        !- Heating Maximum Air Flow Fraction

The DesignSpecification:OutdoorAir object is used to specify how much outdoor air and by what method you will supply to each zone. You can also adjust the sizing factor for cooling and/or heating if needed.

  SZ DSOA SPACE1-1,        !- Name
  sum,                     !- Outdoor Air Method
  0.00236,                 !- Outdoor Air Flow per Person {m3/s-person}
  0.000305,                !- Outdoor Air Flow per Zone Floor Area {m3/s-m2}
  0.0;                     !- Outdoor Air Flow per Zone {m3/s}

  1.0,                     !- Heating Sizing Factor
  1.0,                     !- Cooling Sizing Factor
  ;                        !- Timesteps in Averaging Window
edit flag offensive delete link more


Thank you for the answer given. I'll try and correct it according to your explanation.

Muhammad gravatar imageMuhammad ( 2016-05-25 01:00:26 -0600 )edit

I never knew about the ExampleFiles-ObjectsLink.html file. That is really useful!

Anna Osborne Brannon gravatar imageAnna Osborne Brannon ( 2018-01-08 03:02:15 -0600 )edit

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: 2016-05-23 09:00:27 -0600

Seen: 619 times

Last updated: May 25 '16