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EMS does not turn off ideal load

asked 2025-11-30 23:12:23 -0600

Selma Inger's avatar

updated 2025-12-01 09:18:26 -0600

Dear colleagues,

I am working on the development of mixed-mode ventilation, using EnergyPlus.

My MMV strategy is focused on passive design building with high air tightness (0.05 ACH, referring tothe PassiveHaus standard)

I am using the zone ideal load system and EMS to operate MMV.

My algorithm switches modes according to indoor and outdoor temperature.

EMS turns off zone ideal load system during natural ventilation mode, but in the results, ideal load system is not forced to off.

If you have idea, please share the solutions with me.

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How are you switching modes with EMS? By actuating its availability status? Or overriding its mass flow rate? There are caveats to consider (CTRL-F "Ideal Loads Air System" here). Consider sharing your IDF.

Denis Bourgeois's avatar Denis Bourgeois  ( 2025-12-01 03:44:37 -0600 )edit

I applied only the available schedule and setpoint.

I've attached the idf file.

link text

Selma Inger's avatar Selma Inger  ( 2025-12-01 21:44:43 -0600 )edit

@Selma Inger : IDF v9.4 is pretty old now (circa 2020, pre-ARM installers). Hopefully someone has an E+ v9.4 lying around. You can always share an updated version, e.g. anything above v22.1 (2022).

Denis Bourgeois's avatar Denis Bourgeois  ( 2025-12-02 06:11:01 -0600 )edit

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answered 2025-12-01 11:11:57 -0600

One common approach to disabling an HVAC system using EMS is to change the setpoint schedule so that the setpoint is very high (or low), such that the HVAC system does not need to turn on.

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Yes I did that. But it still operates ideal load system

Selma Inger's avatar Selma Inger  ( 2025-12-01 21:45:19 -0600 )edit

Have you tried using the Output:EnergyManagementSystem object to verify that your EMS program is doing what you expect?

shorowit's avatar shorowit  ( 2025-12-02 10:19:22 -0600 )edit

Another option is to actuate the Heating/Cooling Availability Schedules (e.g., here) instead of the setpoint.

shorowit's avatar shorowit  ( 2025-12-02 10:21:19 -0600 )edit

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Asked: 2025-11-30 23:12:23 -0600

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