Heat Recovery Chiller in OpenStudio

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Thanks for sharing @MatthewSteen. So your approach was to have a separate plant model to determine the annual heating/cooling efficiencies and then you applied those annual COPs to OpenStudio objects to get the final results to display in OpenStudio?

We are often forced to have a 'whole building' model in OS and feed our hydronic loads to a separate 'plant model' in EnergyPlus (we've used TRNSYS in the past as well). It's unfortunate that the actual E+ objects exist in OS but their functionality is compromised. I'm intrigued by the idea of creating an entire E+ plant model and linking it up to the OS model with an E+ measure to get the final results to display in OpenStudio and update with each run as changes are made to the OS model. Not quite sure if this is achievable though.

It looks like the CentralHeatPumpSystem may be available for use in the OS API. Aside from a traditional ground source application, this system can be quite difficult to control.

@Lyle K,

1. Yes, the central plant was modeled in TRNSYS to determine the annual system efficiencies.

2. I considered writing an EP measure to add the CHPS to the OS models by replacing another piece of equipment in a plant loop, since in our case that was the only object that wasn't available in the GUI or API.

3. You're correct the CentralHeatPumpSystem is available in the API, but it doesn't work right now because of its unique topology.

@MatthewSteen - thanks for this nearly-two-year-old comment! I've run into this exact problem, and was considering taking this approach. Out of curiosity, did you simply totalize the hourly energy consumption of all CHW/HW coils, and apply those on the demand side of the water-to-water heat pumps in TRNSYS via an equation block or HX component?

Julien, I just wanted to say that this is great and I am already making use of your work now that OpenStudio 2.4 has been released. I almost have it working on my machine and I'm able to connect up the centralHeatPump to the correct source loop and cooling loop. However, I have been unable to connect it up to the heating loop. All of my attempts to add the centralHeatPump to the heating loop seem to be accidentally assigning it as the cooling loop. Can you offer any advice on how to set this up? If need be, I can just right an E+ measure to correct for this. Thank you!

Can't do it in the GUI. You need to use the API to connect it, via addToTertiaryNode.

Thanks for the response, Julien. I am only using the API and not the GUI. The addToTertiaryNode method worked well to create the right OpenStudio object but I realized that there are a lot of other things that are not working in the resulting IDF, including nodes not being connected up to one another correctly and the heating/cooling plant equipment lists not being written whenever I add the CentralHeatPumpSystem object to a loop. Am I correct in understanding that there's still work to be done to get the class working fully?

Chris, these are clearly all bugs indeed, I was able to reproduce them. I didn't add that many tests (and no actual simulation (regression) test), so I wasn't even aware it wasn't working. I am now, I'll open issues on github.

https://github.com/NREL/OpenStudio/is...