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Steam to HW Loop Error in OpenStudio

asked 2015-01-30 10:58:20 -0500

updated 2015-07-11 14:55:45 -0500

I am working on a project that has a district plant, and due to the fact that it is a LEED project, I need to create a steam to HW plant in my model. I have created two loops, a HW loop with all of my HW coils in the project and a fluid to fluid HX, and a steam loop with a steam boiler and the fluid to fluid HX. image description image description

When I try to run this I get the following error: image description

I have the steam plant sizing set to "steam" with appropriate temps and the plantloop fluid type set to "steam". Has anyone had any experience with this error in OS? It seems like an issue in converting the OS model to a E+ idf. I have had this error any time I try to model a primary/secondary loop with a HX as well. Any insight would be greatly appreciated.

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Taylor, How did you expose the steam boiler? Could you post the script?

JamisonH's avatar JamisonH  ( 2017-05-23 18:04:10 -0500 )edit

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answered 2015-01-30 11:09:09 -0500

updated 2015-01-30 11:10:08 -0500

I'm not sure steam systems are supported in OS yet even though some of the fields are exposed. Have you been able to model them previously? You may have to model it as a water system instead or write an EnergyPlus measure.

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The steam boiler is in the SDK documentation but not in the OS model, so I wrote a script to put it in the OS model. The loops have a steam option, so I assumed it was supported but it might not be.

TaylorRoberts's avatar TaylorRoberts  ( 2015-01-30 11:16:10 -0500 )edit

Matt is correct. Mod him up. Steam systems are not supported in OpenStudio. A couple of the components you need are there (BoilerSteam), but others are not (PumpVariableSpeedCondensate). This is why the steam boiler is not yet included in the HVAC library. At the E+ level, I'm 90% certain the HeatExchangerFluidToFluid model cannot support steam. You could use an IDF Measure to swap the pump out for a condensing pump, but then you would still have to deal with the interface between the steam and fluid plants. I don't believe E+ has a suitable HX model.

Kyle Benne's avatar Kyle Benne  ( 2015-01-30 12:48:47 -0500 )edit

@TaylorRoberts - I think @Kyle Benne is correct that a steam to water HeatExchangerFluidToFluid is not allowed and will cause an EP error. When I've encountered this before I simply used a BoilerHotWater. Haven't heard back from the LEED reviewers yet on it, but I would guess that it won't result in a mandatory response.

MatthewSteen's avatar MatthewSteen  ( 2015-01-30 13:11:02 -0500 )edit

Thanks Matt and Kyle for the help. I will move forward with a HW boiler.

TaylorRoberts's avatar TaylorRoberts  ( 2015-02-02 09:59:53 -0500 )edit

Any plans to implement it in the near future?

Julien Marrec's avatar Julien Marrec  ( 2016-04-01 06:59:14 -0500 )edit

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Asked: 2015-01-30 10:58:20 -0500

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Last updated: Jan 30 '15