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Is it possible to control zone level equipment as secondary and not primary equipment?

asked 2015-04-22 12:07:49 -0500

updated 2015-07-11 17:40:56 -0500

If I ever add zone level equipment as supplemental heating, such as baseboard or radiant floor, I cannot get that equipment to be secondary to the primary equipment, such as a roof top unit. Is it necessary to use energy management system code to implement this type of control or am I missing something? This is very common control and I would assume that it would be easy to implement in the OpenStudio app.

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answered 2015-04-22 13:18:20 -0500

updated 2016-05-09 10:45:33 -0500

At the EnergyPlus level the order in which equipment is simulated and therefore the order that it picks up load is determined by the ZoneHVAC:EquipmentList

In OpenStudio the heating/cooling priority that ends up in the ZoneHVACEquipmentList is determined by the order that components are displayed in the Application. For example in the following example for "Thermal Zone 1" the PTAC is simulated first and the unit heater is simulated second.

image description

It is not possible to reorder equipment in the graphical interface. Instead you need to remove the component(s) and add them in the order that you want them to simulate.


As @Eric Ringold pointed out in a comment below, you can change the heating/cooling priority using a measure with the setCoolingPriority and setHeatingPriority methods.

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I have been wondering about this as well, thanks for the great answer Kyle!

TaylorRoberts gravatar imageTaylorRoberts ( 2015-04-22 15:54:07 -0500 )edit

Wow, I didn't know that a drag/drop feature to rearrange/reorder objects on the roadmap or possible? I've thought this feature would be nice for loops to reorder air-side components or to change plant equipment from parallel to series without losing field entries.

MatthewSteen gravatar imageMatthewSteen ( 2015-04-22 21:36:40 -0500 )edit

FYI, you can change the heating/cooling priority using a measure with the setCoolingPriority and setHeatingPrioritymethods.

Eric Ringold gravatar imageEric Ringold ( 2015-04-22 22:33:30 -0500 )edit

@MatthewSteen drag and drop to rearrange is possible for both zone equipment and system components. Like Eric points out the API supports this, enabling in the user interface just hasn't become high enough priority yet.

Kyle Benne gravatar imageKyle Benne ( 2015-04-23 08:18:56 -0500 )edit

UserVoice feedback to allow rearranging of zone HVAC equipment.

MatthewSteen gravatar imageMatthewSteen ( 2016-03-04 06:14:05 -0500 )edit

answered 2016-04-04 14:04:35 -0500

In the IDF Editor, under ZoneHVAC:Equipement List, you can change the sequence manually by setting up the Zone Equipment Cooling Sequence and Zone Equipment Heating or No-Load Sequence.

"Equipment is simulated in the order specified by Zone Equipment Cooling Sequence and Zone Equipment Heating or No-Load Sequence, depending on the thermostat request. For equipment of similar type, assign sequence 1 to the first system intended to serve that type of load. For situations where one or more equipment types has limited capacity or limited control, order the sequence so that the most controllable piece of equipment runs last. ;"

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Asked: 2015-04-22 12:07:49 -0500

Seen: 283 times

Last updated: May 09 '16