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EMS sensor for HVAC system availability status

asked 2019-02-08 09:02:30 -0600

antoineg's avatar

updated 2019-02-08 09:08:07 -0600


Is there a way to define a sensor that would output HVAC system status, related to its operations schedule?

For instance with this schedule:

HVACOperationSchd,       !- Name
On/Off,                  !- Schedule Type Limits Name
Through: 12/31,          !- Field 1
For: Weekdays SummerDesignDay, !- Field 2
Until: 06:00,0.0,        !- Field 3
Until: 22:00,1.0,        !- Field 5
Until: 24:00,0.0,        !- Field 7
For: Saturday WinterDesignDay, !- Field 9
Until: 06:00,0.0,        !- Field 10
Until: 18:00,1.0,        !- Field 12
Until: 24:00,0.0,        !- Field 14
For: AllOtherDays,       !- Field 16
Until: 24:00,0.0;        !- Field 17

Then the sensor would return 0 until 6am on week days and Saturday, then 1, etc.


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answered 2019-02-10 19:41:25 -0600

You could also add the Schedule Value for this HVACOperationSchd as a normal Output Variable to see it's value reported in a CSV file generated by EnergyPlus. However, this seems to be for determining when an HVAC system is available to operate if a cooling or heating load occurs -- it does not necessarily force the HVAC system to operate during those hours. If you want to see when the HVAC system operates, then add a Output Variable for Air System Electric Energy -- if this output is > 0 , the system is on.

If your air system can cycle, or have different "levels" of availability, then use the Air System Simulation Cycle On Off Status

For more on Output Variables, see this Unmet Hours post.

If these aren't useful, and you really want to create an EMS sensor for HVACOperationSchd, it would look like this:

  HVAC_Sched_Sensor, !- Name
  HVACOperationSchd, !- Output:Variable or Output:Meter Index Key Name
  Schedule Value;    !- Output:Variable or Output:Meter Name

Then, in an EMS Program, you would define your custom logic for how to use HVAC_Sched_Sensor.

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Asked: 2019-02-08 09:02:30 -0600

Seen: 221 times

Last updated: Feb 10 '19