Chiller:Absorption:indirect in ironbug

Hello @MingboPeng
Thank you for your hard work

I want to make a custom HVAC system including an indirect absorption chiller. However, I couldn’t get any information about the indirect absorption chiller anywhere. When referring to the Energy Plus document(Group – Plant Equipment: Input Output Reference — EnergyPlus 24.2), I couldn’t find any such information in the ironbug. It’s not the indirect absorption chiller in the ironbug yet?

Can it be implemented using the string below? If implemented, I wonder how to connect ‘Gener Inlet Node Name’ and ‘Gener Outlet Node Name’ using hot water or steam.

Thank you for your kind reply in advance :slight_smile:

Chiller:Absorption:Indirect,
      Big Chiller,             !- Chiller Name
      100000,                  !- Nominal Capacity {W}
      250,                     !- Nominal Pumping Power {W}
      Big Chiller Inlet Node,  !- Evaporator Inlet Node Name
      Big Chiller Outlet Node, !- Evaporator Outlet Node Name
      Big Chiller Condenser Inlet Node,  !- Condenser Inlet Node Name
      Big Chiller Condenser Outlet Node,  !- Condenser Outlet Node Name
      0.15,                    !- Minimum Part Load Ratio
      1.0,                     !- Maximum Part Load Ratio
      0.65,                    !- Opt Part Load Ratio
      35.0,                    !- Temp Design Condenser Inlet {C}
      10.0,                    !- Temp Lower Limit Condenser Inlet {C}
      5.0,                     !- Chilled Water Outlet Temperature Lower Limit {C}
      0.0011,                  !- Design Chilled Water Flow Rate {m3/s}
      0.0011,                  !- Design Condenser Water Flow Rate {m3/s}
      VariableFlow,            !- Chiller Flow Mode
      SteamUseFPLR,            !- Generator Heat Input function of part-load ratio curve name
      PumpUseFPLR,             !- Pump Electric Input function of part-load ratio curve name
      AbsorberSteamInletNode,  !- Generator Inlet Node Name
      AbsorberSteamOutletNode, !- Generator Outlet Node Name
      CAPfCOND,                !- Capacity Correction function of condenser temperature curve name
      CAPfEVAP,                !- Capacity Correction function of evaporator temperature curve name
      ,                        !- Capacity Correction function of generator temperature curve name
      SteamFCondTemp,       !- Generator Heat Input Correction function of condenser temperature curve name
      SteamFEvapTemp,       !- Generator Heat Input Correction function of evaporator temperature curve name
      Steam,                   !- Generator Heat Source Type
      autosize,                !- Design Generator Volumetric Fluid Flow Rate {m3/s}
      30.0,                    !- Temp Lower Limit Generator Inlet {C}
      2.0,                     !- Degree of Subcooling in Steam Generator {C}
      12.0;                    !- Degree of Subcooling in Steam Condensate Loop {C}

Hi @Taek, I have not implemented the “Chiller:Absorption:Indirect” in the Ironbug. But I just checked the OpenStudio SDK, and they have added it, so it should be possible to support it in Ironbug.

In terms of this specific object, “Chiller:Absorption:Indirect”, I have never used previously, and I’m not sure how to make it work correctly with a generator loop. It’d take me some time to study and test it on my end.

If you could provide a simple sample file (EnergyPlus idf or OpenStudio osm file) for me to better understand this object, that would be great and speed up the Ironbug implementation.

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Thanks for your response, @MingboPeng. I’m excited about the possibility of using various equipment in Ironbug. I think I can provide the IDF file for the “Chiller:Absorption:Indirect” that was implemented in DesignBuilder.
Chiller;Absorption;indirect.idf (174.4 KB)

This file configures the PlantLoop with one Chiller and one Condenser. As I understand “Chiller:Absorption:Indirect” , a separate HotWater loop using hot water (or steam) is required to measure the heat absorbed by the Chiller. Additionally, this Boiler is connected to the Chiller on a 1:1 basis, allowing the gas consumption used by the Boiler to be calculated.

I know there are many types of equipment, and I look forward to the day when various equipment can be used in Ironbug!

Thanks a lot for your great work.

1 Like

Hi @Taek, thanks for your sample file and that’s really helpful.
I just added a new ChillerAbsorptionIndirect in Ironbug (download a new version v1.16 from here), and here is the sample Grasshopper file that I try to recreate the system based on your sample idf.

I didn’t get a chance to run this system with a project, but please let me know if everything works as expected.

ChillderAbsorptionIndirect.gh (74.6 KB)

Here is the generated OpenStudio from above Grasshopper file, in case you want to take a look.
ChillerAbsInd.osm (81.9 KB)

Chilled water loop

Condenser water loop

Hot water loop

2 Likes

Hello @MingboPeng , your support has been incredibly helpful. :smiley:

I updated the sample Ironbug file by applying the VAV Reheat System with the Chiller:Absorption:Indirect to four sample zones.

250119_Chiller;Absorption;indirect with VAV Reheat.gh (93.0 KB)

After reviewing it in the OpenStudio application, I confirmed that the chiller and boiler are successfully connected!! :smiley:
One boiler is properly connected to the heating coil of the air loop, and the other boiler is successfully connected to the chiller.

250119_Chiller;Absorption;indirect with VAV Reheat.osm (405 KB)


Upon reviewing the IDF file, I confirmed that the Chiller:Absorption:Indirect is operating correctly.
250119_Chiller;Absorption;indirect with VAV Reheat.idf (351.1 KB)

Everything appears to be functioning correctly from my perspective. If there’s anything I might have missed or done incorrectly, could you please let me know?

I truly appreciate it—thank you so much!

1 Like