Number of Chiller Heater Modules in Central Heat Pump System

Hi @MingboPeng

I’m modelling a centralized geothermal heat pump system, and I’ve noticed that changing the Number of Chiller Heater Modules with Ironbug doesn’t reflect correctly in the IDF file, as it remains set to 1 regardless of the input. As for OpenStudio, I couldn’t find where this value is indicated (as well as the name I set). The rest of the values like ancillary power, schedules and performance values are converted correctly.

Since I’ve never modelled this system before, I’m unsure if this discrepancy is an error or a simplification of the system.


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Hi @MatteoMerli, to be honest, I have worked on a project with GSHP several years ago and I was never to be able to get it working and the results make sense. I am not sure how comfortable for you to test this system within OpenStudio or EnergyPlus, but if yes, it would be helpful to create a prototype first and I can help you after that point.

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Thank you @MingboPeng.

I’ve read a few threads on Unmet Hours and GitHub’s open issues regarding the chiller-heater system’s concerns.
However, we may still need to proceed with modelling this system as it closely aligns with our case. I’d be happy to share it with you once we’ve modelled it in more detail, with the hope of achieving reasonable results.

  1. Did you also encounter any problems with the simplified model of the ground source system, without the central heat pump?

  2. It’s not entirely clear from your reply whether the incorrect transcription of the number of chiller heater modules is simply a bug. Do you think you can easily fix this?

Hi @MatteoMerli, I looked around for any sample files or more detailed documentation besides E+ docs, and no luck. But based on the E+'s doucuments, I still couldn’t figure out how CentralHeatPumpSystemModule should be setup with the CentralHeatPumpSystem correctly.

On Ironbug side, I override user’s input for NumberOfChillerHeaterModules to be 1. It might be a bug or an idea of how I understood the way this system should be set at that time. I don’t see any problem in removing this limitation, and I just pushed a new update of Ironbug, which should allow you to manually set NumberOfChillerHeaterModules. The new version of the Ironbug should be ready in about an hour. Let me know if it works as expected.

I saw your post on Unmet Hours, and I would also like to hear any updates on that.

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Hi @MingboPeng, thanks for the fast and effective support. Now I can manually set the number of chiller heater modules.

After installing the new update of Ironbug, I’m running into these Grasshopper Loading Errors, and I can’t find the district heating components in Ironbug. Did I do something wrong in the update, or is it something else?

Hi @MatteoMerli, how did you install the previous version of Ironbug? Do you use the Pollination Grasshopper installer?
The issues come from the outdated OpenStudio 3.6. If you use the new OpenStudio 3.7, which supports the new DistrictHeatingStream, it will solve your loading issue.

Yes I installed the previous version through the Pollination Installer v.1.43.6 (LB 1.7.5 and OS 3.6). I just installed Pollination again (v.1.47.3), updated Ironbug and went back to LB 1.7.5 using the LB versioner (to keep the same version of the rest of the office). I don’t know if there was a faster way of replacing the OS version in the ladybug_tools folder without messing with anything. If there is, I’m all ears!

However, everything’s working fine now. Thank you a lot for your help @MingboPeng.

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