RE: [EnergyPlus_Support] Dynamically Changing System AirFlow

Thanks Jean, I think I am doing that now by scheduling the damper (dynamic changes by EMS via a year schedule), but it is not working as well as I would like. I have to also schedule the outdoor air to get the zone schedules to work, otherwise it runs full volume. While this seems to make a change in energy use, the main system still runs at full flow so the fan power remains constant (and the air goes ??). The zone changes are not moving backward through the system. This may be because of some other of my EMS controls. The supply air temp for the air loop is reset with inputs from zone air temperature and the space temperature is controlled by baseboard thermostats. I’m going to try to set the flows in the air loop and see if that varies the fan power.

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
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From: EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]
Sent: Tuesday, December 13, 2016 12:58 AM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Dynamically Changing System AirFlow

Hi Ned,

The last time I did that sort of control, I only controlled the terminal dampers (variable flow). Same as in real life really. And the effect, worked back to the AHU.

On 12 Dec 2016 6:33 pm, "'Edward G. Lyon' eglyon@xxxxxxx [EnergyPlus_Support]" <EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:

I have a model with an 8 zone VAV system. To model my building, I have forced to system to operate at maximum flow and 100% outside air. The actual building air flow is 100% outdoor air with total flow adjusted dynamically by a monitor I can’t duplicate easily (how active a cooking grill is). I tried using an EMS routine to reset the air flow mass at the inlet node of the zone terminal units using a mass flow schedule. The EDD file shows that my calculations are working, but the CSV file flow and energy use are not changing. (I’ve tried alternate EMS calculation points to no avail.)

My question is do I have to reset all node flows in the air loop model to force the system to calculate at a different total air flow rate, or is there some other node location (like mixed air outlet) that would ripple the change through the system?

Thanks in advance�

Ned Lyon, P.E. (MA, WV)
Staff Consultant

SIMPSON GUMPERTZ & HEGER
| Engineering of Structures and Building Enclosures

41 Seyon Street, Bldg. 1, Suite 500
Waltham, MA 02453

781.907.9000 main
781.907.9350 direct
617.285.2162 mobile
781.907.9009 fax
www.sgh.com

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Posted by: "Edward G. Lyon" <EGLyon@xxxxxxx>

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