LBT 1.5 and ironbug VRF+DOAS running error


I used a simple box for test Ironbug with VRF+DOAS. I just used the default setting of the system. After re-run osm file, it return some errr about this system.

1. ** Severe ** Node NODE 13 connects to no component
2. ** Severe ** An outlet node in AirLoopHVAC=“DOAS” is not connected to any zone
Maybe the HVAC template is not very suitable for VRF+DOAS system.
The pollination version is plugins_dev_PollinationGHPluginInstaller-1.18.2.
Please help me debug this error @MingboPeng

VRF+DOAS error.gh (36.5 KB)

Full message is here

Program Version,EnergyPlus, Version 22.1.0-ed759b17ee, YMD=2022.12.22 17:41,
   ** Warning ** CheckEnvironmentSpecifications: SimulationControl specified doing design day simulations, but no design environments specified.
   **   ~~~   ** ...No design environment results produced. For these results, add appropriate SizingPeriod:* objects for your simulation.
   ** Warning ** ProcessScheduleInput: Schedule:Constant="ALWAYS OFF DISCRETE", Blank Schedule Type Limits Name input -- will not be validated.
   ** Warning ** ProcessScheduleInput: Schedule:Constant="ALWAYS ON CONTINUOUS", Blank Schedule Type Limits Name input -- will not be validated.
   ** Severe  ** Node NODE 13 connects to no component
   **   ~~~   ** Occurs in Supply Air Path=DOAS NODE 3 SUPPLY PATH
   **   ~~~   ** Check the connection to a ZoneHVAC:EquipmentConnections object
   **   ~~~   ** Check if this component is missing from the Supply Air Path
   ** Severe  ** An outlet node in AirLoopHVAC="DOAS" is not connected to any zone
   **   ~~~   ** Could not match ZoneEquipGroup Inlet Node="NODE 3" to any Supply Air Path or controlled zone
   **  Fatal  ** Preceding errors cause termination
   ...Summary of Errors that led to program termination:
   ..... Reference severe error count=2
   ..... Last severe error=An outlet node in AirLoopHVAC="DOAS" is not connected to any zone
   ************* Warning:  Node connection errors not checked - most system input has not been read (see previous warning).
   ************* Fatal error -- final processing.  Program exited before simulations began.  See previous error messages.
   ************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
   ************* EnergyPlus Sizing Error Summary. During Sizing: 0 Warning; 0 Severe Errors.
   ************* EnergyPlus Terminated--Fatal Error Detected. 3 Warning; 2 Severe Errors; Elapsed Time=00hr 00min  0.21sec

Runtime error (PythonException):    **  Fatal  ** Preceding errors cause termination

Traceback:
  line 126, in run_osm_and_report_errors, "<string>"
  line 180, in run_function_in_parallel, "C:\Program Files\ladybug_tools\python\Lib\site-packages\ladybug_rhino\grasshopper.py"
  line 154, in script

Try LBT 1.4.0 to produce the base .osm file that you are overwriting and plugging in the newfilepath input field

Hi,@Mo This error maybe is a bug about ironbug, not about LBT.

Hi @minggangyin

From the error message, you are not adding the system correctly.
This is the right way to add a system to osm model:

1 Like

@MingboPeng Thanks for your answer.You are right.I follow your workflow, openstudio can run without this error. But it return another error. It is a bug about Cooling Capacity Ratio Modifier Function\cooling Energy Input Ratio Modifier Function\Heating Energy Input Ratio Modifier Function.

Program Version,EnergyPlus, Version 22.1.0-ed759b17ee, YMD=2022.12.27 13:07,
   ************* Beginning Zone Sizing Calculations
   ** Warning ** Weather file location will be used rather than entered (IDF) Location object.
   **   ~~~   ** ..Location object=SITE 1
   **   ~~~   ** ..Weather File Location=Shanghai-Hongqiao.Intl.AP SH CHN SRC-TMYx WMO#=583670
   **   ~~~   ** ..due to location differences, Latitude difference=[31.20] degrees, Longitude difference=[121.34] degrees.
   **   ~~~   ** ..Time Zone difference=[8.0] hour(s), Elevation difference=[300.00] percent, [3.00] meters.
   ** Warning ** ProcessScheduleInput: Schedule:Constant="ALWAYS OFF DISCRETE", Blank Schedule Type Limits Name input -- will not be validated.
   ** Warning ** ProcessScheduleInput: Schedule:Constant="ALWAYS ON CONTINUOUS", Blank Schedule Type Limits Name input -- will not be validated.
   ** Warning ** GetHTSurfaceData: Surfaces with interface to Ground found but no "Ground Temperatures" were input.
   **   ~~~   ** Found first in surface=ROOM_1_3F11F482..FACE4
   **   ~~~   ** Defaults, constant throughout the year of (18.0) will be used.
   ** Warning ** CheckUsedConstructions: There are 13 nominally unused constructions in input.
   **   ~~~   ** For explicit details on each unused construction, use Output:Diagnostics,DisplayExtraWarnings;
   ************* Beginning System Sizing Calculations
   ** Warning ** GetVRFInput: AirConditioner:VariableRefrigerantFlow="AIR CONDITIONER VARIABLE REFRIGERANT FLOW 1" curve values
   **   ~~~   ** ... Cooling Capacity Ratio Modifier Function of Low Temperature Curve Name = AIR CONDITIONER VARIABLE REFRIGERANT FLOW 1 VRFCOOLCAPFT output is not equal to 1.0 (+ or - 10%) at rated conditions.
   **   ~~~   ** ... Curve output at rated conditions = 1.136
   ** Warning ** GetVRFInput: AirConditioner:VariableRefrigerantFlow="AIR CONDITIONER VARIABLE REFRIGERANT FLOW 1", invalid
   **   ~~~   ** ...Cooling Energy Input Ratio Modifier Function of Low Part-Load Ratio Curve Name = AIR CONDITIONER VARIABLE REFRIGERANT FLOW 1 COOLINGEIRLOWPLR has out of range value.
   **   ~~~   ** ...Curve minimum value of X = 0.500 must be <= Minimum Heat Pump Part-Load Ratio = 0.250.
   ** Warning ** GetVRFInput: AirConditioner:VariableRefrigerantFlow="AIR CONDITIONER VARIABLE REFRIGERANT FLOW 1", invalid
   **   ~~~   ** ...Heating Energy Input Ratio Modifier Function of Low Part-Load Ratio Curve Name = AIR CONDITIONER VARIABLE REFRIGERANT FLOW 1 HEATINGEIRLOWPLR has out of range value.
   **   ~~~   ** ...Curve minimum value of X = 0.500 must be <= Minimum Heat Pump Part-Load Ratio = 0.250.
   **  Fatal  ** GetVRFInput: Errors found in getting AirConditioner:VariableRefrigerantFlow system input. Preceding condition(s) causes termination.
   ...Summary of Errors that led to program termination:
   ..... Reference severe error count=0
   ..... Last severe error=
   ************* Warning:  Node connection errors not checked - most system input has not been read (see previous warning).
   ************* Fatal error -- final processing.  Program exited before simulations began.  See previous error messages.
   *************
   ************* ===== Final Error Summary =====
   ************* The following error categories occurred.  Consider correcting or noting.
   ************* Nominally Unused Constructions
   ************* ..The nominally unused constructions warning is provided to alert you to potential conditions that can cause
   ************* ..extra time during simulation. Each construction is calculated by the algorithm indicated in the HeatBalanceAlgorithm
   ************* ..object. You may remove the constructions indicated (when you use the DisplayExtraWarnings option).
   *************
   ************* EnergyPlus Warmup Error Summary. During Warmup: 0 Warning; 0 Severe Errors.
   ************* EnergyPlus Sizing Error Summary. During Sizing: 8 Warning; 0 Severe Errors.
   ************* EnergyPlus Terminated--Fatal Error Detected. 8 Warning; 0 Severe Errors; Elapsed Time=00hr 00min  0.24sec

Runtime error (PythonException):    **  Fatal  ** GetVRFInput: Errors found in getting AirConditioner:VariableRefrigerantFlow system input. Preceding condition(s) causes termination.

Traceback:
  line 126, in run_osm_and_report_errors, "<string>"
  line 180, in run_function_in_parallel, "C:\Program Files\ladybug_tools\python\Lib\site-packages\ladybug_rhino\grasshopper.py"
  line 154, in script

Thanks for reporting.
This was because the new version of E+ has a different requirement than what default value that comes from OpenStudio. You can set this VRF’s MinimumHeatPumpPartLoadRatio to 0.5 to fix the issue. Meanwhile, I will add this setting to the template.

3 Likes

Thanks @MingboPeng After set this parameter, VRF+DOAS system worked fine.

Hi @minggangyin,

In case you need it. Here is a complete realistic VRF system with all cooling and heating performance curves that I referenced from this : openstudio-standards

VRF+DOAS_MP.gh (77.1 KB)

2 Likes

Thanks for that @MingboPeng! great work really. I have a question, if I have 10 rooms divided into two zones… they share the DOAS, however, some rooms are served with VRF, while others have fan coil units. How can I combine both? can you post a small example please?
Testing HVACS3.gh (207.5 KB)

Hi @Mo,

I drew a quick diagram here. Hopefully, this is easy to understand.

3 Likes