Re: [EnergyPlus_Support] do I need a return outlet node for each zone?

vincent

On Thu, May 17, 2012 at 7:27 PM, YuanLu Li <yli006@xxxxxxxxxxx> wrote:

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Call R3 the plenum and use it as a mixer to return the zone air. (R1 + R2)
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Plenum is declared as a zone and behaves like a zone.
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It becomes confusing, when the syntax in the later versions made it part of the mixer in the air return parth.
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Plenum may have external walls and inter-zone surfaces, and should be equivalent to R3.
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The doors can remain closed in the simulation, and the room air will still flow into the R3 (plenum).

The heat exchanger should be better defined, as a heating coil, etc.Â are also heat exhangers.Â

The normal EPlus model is to use an outside air mixer heating/cooling coil's and a fan.Â The fan defines the air flow amount.Â The outlet from this is fed to the zones through a splitter.Â The air from the zone mixer (plenum) is return to the return mode of the OA mixer.Â Part of te return air is recycled to the zone.Â The OA inlet air intake amount is exhausted through the relief node of the OA mixer.
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The OA inlet mixed with part of the zone return air is fed to the heating/couling unit at the MixedAir node.Â The OA mixer is actually a mixer and a splitter with a by-pass for the return air.
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There is an actuator at the OA inlet node which can be controlled with a schedule and a controller.

If the doors are always open, thenÂ the building can be modeled as a one zone building.Â Â
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If the air does not flow when the doors are closed, then there must be some other air paths for R1 and R2.

EPlus can do many tifferent forms of modelling for the air aflow.Â In the usual heat balance model, the position and size of the inlet and outlet port need not be defined.Â Equal amount of air is added and extracted to the zone for heat transfer canculation.Â The fan flow volume is used to determine the air exchanged per time step.
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A zone is also a mixer and splitterÂ conbined.Â It has two inlets and two outlets.Â However, the four nodes must be used as defined by the object requirement of the program.Â This concept make it easier to understand the zone air Â infiltration and ventilation objects when added to the zone.
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Â Dr. LiÂ Â

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To: EnergyPlus_Support@xxxxxxxxxxxxxxx
From: vlacour@xxxxxxxxx
Date: Thu, 17 May 2012 14:50:28 +0200
Subject: [EnergyPlus_Support] do I need a return outlet node for each zone?

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I am trying to use energy plus for a three-zone building where outside air is supplied to room 1 and 2 to through a heat exchanger and a splitter and returned through an outlet node from room 3. Â The air flow uses doors between room 1 and room 3, and between room 2 and room 3 to reach the return path. Â

The issue is that if I consider each room as a separate zone, I take from E+ documentation that I need a return outlet node in each zone when I would prefer to stick to the actual flows from R1 to R3 and from R2 to R3.

What should I do?

thanks in advance.

Vincent