EMS control of supply air flow and temperature in EnergyPlus

asked 2023-07-06 10:45:38 -0500

Sdrd's avatar


I'm asking this question on this forum because I'm experiencing a problem for which I haven't found a solution. I have a single-zone building served by a VAV system with terminal. I know the supply air temperature and flow rate at each time step (10 minutes) of the study year. Values are implemented as Schedule:File. I'd like to use these values to calculate energy consumption instead of those automatically calculated by EnergyPlus.

The solution lies in the use of EMS programs, but I haven't found anything conclusive on how to go about it. I need to define an actuator for temperature and supply air flow in the zone, and create a program to match the values at each time step with those in the schedules.

Do you have a solution?

Have a nice day.

edit retag flag offensive close merge delete


@Sdrd does this post help?

Aaron Boranian's avatar Aaron Boranian  ( 2023-07-13 14:42:26 -0500 )edit

Hello @Aaron Boranian,

Thank you for your reply. Yes, this post helps in part, but it highlights several constraints.

First, it seems that it is only possible to control "AirTerminal:SingleDuct:ConstantVolume:NoReheat". So, as I have a heating terminal and the system is VAV, I have to convert my entire system to CAV (without the heating terminal) and control it as VAV using my values and the EMS tool. As a result, I'm losing information about the energy consumption of my terminal.

Sdrd's avatar Sdrd  ( 2023-07-14 11:41:23 -0500 )edit

The biggest problem is if there are several zones. As there can be no terminals, the supply temperature must vary identically in all zones. Which is never the case.

In conclusion, I think it's hardly feasible. It forces you to modify the whole structure of the system, you lose information, and it's only applicable in rare cases. Perhaps there's another program that can do this kind of analysis...

Sdrd's avatar Sdrd  ( 2023-07-14 11:45:04 -0500 )edit

@Sdrd In that case, would the Hybrid Model feature of EnergyPlus work? This allows you to set zone air temperature and supply air temperature as a schedule.

Aaron Boranian's avatar Aaron Boranian  ( 2023-07-17 14:37:46 -0500 )edit

This feature is primarily used so that EnergyPlus can inversely solve for other zone heat balance components that are difficult to measure (internal thermal mass, infiltration rate, etc.).

Aaron Boranian's avatar Aaron Boranian  ( 2023-07-17 14:38:44 -0500 )edit