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Actuate coil capacities with EMS?

asked 2020-11-04 20:18:39 -0500

updated 2020-11-05 09:03:35 -0500

Hi, there,

I need some help on a case where I want to change the cooling and heating coil capacities dynamically under some condition (through EMS program). Systems are fixed-sized in idf, I've tried the Unitary HVAC Design Heating Capacity and Unitary HVAC Design Cooling Capacity, but they're not working. Is it feasible to actuate capacities in E+? Any suggestions?


Test file if you're interested:

  1. With Unitary HVAC Design Capacity actuators
  2. Without actuators
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answered 2020-11-08 12:25:53 -0500

updated 2020-11-08 12:30:50 -0500

The Unitary HVAC Design Heating Capacity and Unitary HVAC Design Cooling Capacity options that you're using are internal variables -- items that are set once at the beginning of a simulation and don't change (zone floor area, sizing results, etc.). That's why they're not working to dynamically change the coil capacity. To do that, you should instead use actuators. EnergyPlus only has a specific pre-defined list of actuators that you can change -- you don't have the capability to change ANY detail of the model. For cooling coils, it looks like the only actuator available related to capacity is specifically for autosized capacity of single speed DX coils. There don't appear to be any options for actuators related to capacity of heating coils.

There are two workarounds that you could explore to "force" the coils to provide a specific capacity -- the actuators for node setpoints (flow rate, temperatures, and possibly humidity) and the actuator for the performance curve results.

You can read this post for more details.

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Thanks, Aaron. Your answer is very useful!

Yueyue_Zhou's avatar Yueyue_Zhou  ( 2021-01-13 16:17:37 -0500 )edit

answered 2020-11-08 11:37:28 -0500

You have to navigate the EDD output file. To get it, you need to place an Output:EnergyManagementSystem object in the IDF file, with at Actuator Availability Dictionary Reporting at least filled with "NotByUniqueKeyNames" to find the actuator type you need

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Thanks, I did so but I didn't find useful actuators so I was wondering whether it's something feasible to do via EMS.

Yueyue_Zhou's avatar Yueyue_Zhou  ( 2021-01-13 16:15:23 -0500 )edit

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Asked: 2020-11-04 20:18:39 -0500

Seen: 475 times

Last updated: Jan 13 '21