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Pump Pressure Rise EMS Actuator

asked 2018-09-04 14:50:52 -0500

jt1234's avatar

updated 2018-09-04 15:11:48 -0500

The EMS Guide doesn't define the 'Pump Pressure Rise' actuator and its not entirely clear what this is actuator is controlling. Intuitively, I thought this was the pump head but adjusting this value in the EMS program yields results that lead me to believe this is not a correct assumption. Can someone clarify what this actuator is controlling and if there is a hourly variable I can produce to track it?

For further background, I have an EMS program created (via OpenStudio IDF inject) to control a standard series chiller configuration. The measure controls the chillers appropriately, but now I'm working to adjust the pumping to account for the scenario when the loop bypasses the downstream chiller during low-load conditions (lower overall pressure drop). I'm working in OpenStudio v2.6 / EnergyPlus v8.9.

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answered 2018-09-05 20:40:31 -0500

EMS actuator "Pump Pressure Rise" [Pa] is used as the pump head to calculate the pump power:

Power = VolFlowRate * PumpEquip(PumpNum).EMSPressureOverrideValue / TotalEffic;

The doc omission has been added to issue #6717.

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In other words, it's the pump head in Pascal (Pa). What in the results are you seeing makes you believe this wasn't it @jt1234?

Julien Marrec's avatar Julien Marrec  ( 2018-09-06 02:37:49 -0500 )edit

In one example I'm working to mimic a scenario where a constant flow condenser water pump bypasses specific equipment at certain conditions. At this condition, I'm trying to have the actuator reduce the design head of 269,000 Pa down to 210,000 Pa.

Unfortunately setting the pump pressure rise actuator to 210,000 Pa almost triples the total pump energy so clearly I'm doing something wrong.

jt1234's avatar jt1234  ( 2018-09-20 05:55:50 -0500 )edit

Is it possible that your model already is using pump pressure curves? If you'd like someone to diagnose this, please post the idf file here or send it to the helpdesk at

MJWitte's avatar MJWitte  ( 2018-09-24 16:50:56 -0500 )edit

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Asked: 2018-09-04 14:50:52 -0500

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Last updated: Sep 05 '18