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[EnergyPlus_Support] Re: Air flow from one zone to another: extraction to return air duct

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: Air flow from one zone to another: extraction to return air duct
From: "joskenzy" <joskenzy@xxxxxxxxx>
Date: Thu, 26 Feb 2009 08:42:42 -0000
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While trying to implement your suggestion, I found another problem:

For the first zone, I defined an AirTerminal:SingleDuct:VAV:Reheat and 
this object is than used in a new ZoneHVAC:AirDistribution unit. I 
made the ZoneHVAC:EquipmentList (also including an exhaust fan) and 
next the ZoneHVAC:EquipmentConnections. For zone 1, I've defined an 
inlet node list, an exhaust node and a return air node (I've connected 
the return air node to my ZoneMixer).

Then for zone 2, I was planning to use the outlet air node of the zone 
1 exhaust fan as the zone 2 inlet air node. However: I can't define a 
ZoneHVAC:EquipmentConnections object without first defining a 
ZoneHVAC:AirDistributionUnit for zone 2. As I've told you: there 
actually is no conditioned air distributed in zone 2, so this is a new 
problem.

Again, thank you for your help.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad 
<RRaustad@...> wrote:
>
> No, do not use a new AirTerminal. Just define an inlet and exhaust 
node 
> name for zone 2 and an inlet node name for zone 3 the same way you 
did 
> for zone 1.The name of the inlet node in zone 2 is the same as the 
> exhaust fan outlet node name from zone 1. Use the exhaust node name 
from 
> zone 2 as the exhaust fan inlet node name and the inlet node name in 
> zone 3 as the exhaust fan outlet node name for the exhaust fan that 
> connects zone 2 and 3.. Yes, the node names define the connection. 
> Again, I'm not sure this will work, but I can't think of anything 
else 
> other than deleting the exhaust fan in zone 1 and using the RA from 
zone 
> 1 to increase the flow through the HX. If you choose to delete the 
> exhaust fan in zone 1, ignore the warning of flow imbalance in zone 
1. 
> Make sure you check the RA, SA, and EA flow rates in zone 1, 2 and 3 
no 
> matter which method you use.
> 
>   ZoneHVAC:EquipmentConnections,
>     RESISTIVE ZONE,          !- Zone Name
>     Zone1Equipment,          !- Zone Conditioning Equipment List 
Name
>     Zone1Inlets,             !- Zone Air Inlet Node or NodeList Name
>     ,                        !- Zone Air Exhaust Node or NodeList 
Name
>     Zone 1 Node,             !- Zone Air Node Name
>     Zone 1 Outlet Node;      !- Zone Return Air Node Name
> 
>   NodeList,
>     Zone1Inlets,             !- Name
>     Zone 1 Inlet Node;       !- Node 1 Name
> 
> 
> joskenzy wrote:
> >
> > This is probably not a smart question, but I am new to EnergyPlus 
so 
> > forgive me for
> > asking: how can i connect the outlet node of an exhaust fan to a 
zone 
> > node?
> >
> > I am not using the AirflowNetwork, so I don't have air 
distribution 
> > nodes in my zones...
> > Do you mean I have to define a new 
> > AirTerminal(SingleDuct:Uncontrolled), and use the
> > outlet node of the exhaust fan as the air inlet node of this 
> > AirTerminal-object? I thought
> > this was just a matter of giving nodes a name, I didn't think they 
> > were connected just by
> > using the same name?
> >
> > Thanks again..
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad 
> > <RRaustad@> wrote:
> > >
> > > Yes, that would be thermally incorrect, but at least you would 
have the
> > > air balance on the RA nodes. You just want to get as close as 
possible
> > > with the tools you have available. The only other thing I can 
think of
> > > is to use a zone exhaust in zone 1 and connect the exhaust fan 
outlet
> > > node to an inlet node in zone 2, and the zone exhaust fan outlet 
from
> > > zone 2 to an inlet node in zone 3. I have tried this before but 
can't
> > > recall what happened. If that works, you would not have to use 
the
> > > mixing objects. There would of course be fan heat involved in 
moving 
> > the
> > > air so adjust the fan power down as far as you can go.
> > >
> > > joskenzy wrote:
> > > >
> > > > There is no RA flow rate in zone 1, because I use a 
> > Fan:ZoneExhaust in
> > > > this zone. By doing
> > > > so, the flow balance in zone 1 is correct.
> > > >
> > > > To keep things simple, I first wanted to delete the 
> > Fan:ZoneExhaust in
> > > > zone 1 and use the
> > > > corresponding RA flow rate from this zone in the return duct, 
but 
> > this
> > > > is thermally
> > > > incorrect: the air passing from zone 1 first heats zone 2 and 
then 
> > the
> > > > air from zone 2
> > > > heats zone 3: the RA from zone 3 will be cooler than the RA 
from 
> > zone 1..
> > > >
> > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > > > <RRaustad@> wrote:
> > > > >
> > > > > Wait a minute, if the air from zone 1 is moved to zone 2 and 
3 using
> > > > > mixing objects, isn't there a RA flow rate on zone 1 
already?
> > > > >
> > > > > Richard Raustad wrote:
> > > > > >
> > > > > > How about trying to connect the outlet node of the 
> > Fan:ZoneExhaust
> > > > to a
> > > > > > new inlet node in zone 1 (and disregard the flow imbalance 
> > warnings in
> > > > > > zone 3). Does this give you a RA flow rate in zone 1?
> > > > > >
> > > > > > joskenzy wrote:
> > > > > > >
> > > > > > >
> > > > > > > No I haven't, but I don't really see how this could 
solve my
> > > > problem:
> > > > > > >
> > > > > > > 1) If I use a Fan:ZoneExhaust in zone 3, the air flow 
balance
> > > > for this
> > > > > > > zone will fail (there is
> > > > > > > no supply air, no return air, only exhaust air) ? I 
believe
> > > > ZoneMixing
> > > > > > > is not taken into
> > > > > > > account in the air flow balance?
> > > > > > >
> > > > > > > 2) If I connect the Fan:ZoneExhaust in zone 3 to the air 
inlet
> > > > node of
> > > > > > > my heat exhanger
> > > > > > > (HeatExchanger:Dessicant:BalancedFlow), than I cannot 
> > connect the
> > > > > > > return air duct of the
> > > > > > > other zones (there are 14 other VAV-zones in my 
building, 
> > apart from
> > > > > > > the 3 zones
> > > > > > > considered in my example) to this HX ?
> > > > > > >
> > > > > > > Thank you anyway, I appreciate your effort!
> > > > > > >
> > > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard 
Raustad
> > > > > > > <RRaustad@> wrote:
> > > > > > > >
> > > > > > > > Have you tried connecting the outlet of the 
> > Fan:ZoneExhaust in
> > > > zone
> > > > > > > 3 to
> > > > > > > > the heat exchanger ?
> > > > > > > >
> > > > > > > > joskenzy wrote:
> > > > > > > > >
> > > > > > > > > Could anyone help me implement the following 
ventilation
> > > > concept:
> > > > > > > > >
> > > > > > > > > Say the building has 3 zones: treated air
> > > > (SingleDuct:VAV:Reheat) is
> > > > > > > > > injected in the first zone. The same air flow rate 
passes
> > > > from the
> > > > > > > > > first, through the second and into the third zone.
> > > > > > > > >
> > > > > > > > > There is no treated air injected in the second or 
the third
> > > > zone.
> > > > > > > > >
> > > > > > > > > An air flow rate equal to the injection rate in zone 
1 is
> > > > extracted
> > > > > > > > > from zone 3.
> > > > > > > > >
> > > > > > > > > Normally, one would suggest to supply air to zone 1 
and 
> > to use a
> > > > > > > > > Fan:ZoneExhaust to balance air flows. Using 
ZoneMixing, 
> > you can
> > > > > > > > > simulate air flowing from zone 1 to zone 2, and air 
flowing
> > > > from
> > > > > > zone
> > > > > > > > > 2 to zone 3.
> > > > > > > > >
> > > > > > > > > However (now comes the hard part): the building has 
other
> > > > > > VAV-balanced
> > > > > > > > > zones, and I want to add the extracted air from zone 
3 to
> > > > the return
> > > > > > > > > duct of the other zones because the return air is 
used in a
> > > > heat-
> > > > > > > > > exchanger.
> > > > > > > > >
> > > > > > > > > So for zone 3, I have an air flow entering the zone 
because
> > > > of the
> > > > > > > > > ZoneMixing (zone 2 as source zone), but how can I 
add the
> > > > replaced
> > > > > > > > > zone air to the air in the return duct?
> > > > > > > > >
> > > > > > > > > I looked at the manual and at previous topics here, 
but I
> > > > only found
> > > > > > > > > that ZoneMixing adds air to a zone, while supposing 
an equal
> > > > > > flow rate
> > > > > > > > > has left the zone (without knowing where the air 
went)..
> > > > > > > > >
> > > > > > > > > I would really appreciate your help!
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > > --
> > > > > > > > Richard A. Raustad
> > > > > > > > Senior Research Engineer
> > > > > > > > Florida Solar Energy Center
> > > > > > > > University of Central Florida
> > > > > > > > 1679 Clearlake Road
> > > > > > > > Cocoa, FL 32922-5703
> > > > > > > > Phone: (321) 638-1454
> > > > > > > > Fax: (321) 638-1439 or 1010
> > > > > > > > Visit our web site at: http://www.fsec.ucf.edu 
> > <http://www.fsec.ucf.edu>
> > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>
> > > > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>>
> > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>
> > > > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>>>
> > > > > > > >
> > > > > > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > > > --
> > > > > > Richard A. Raustad
> > > > > > Senior Research Engineer
> > > > > > Florida Solar Energy Center
> > > > > > University of Central Florida
> > > > > > 1679 Clearlake Road
> > > > > > Cocoa, FL 32922-5703
> > > > > > Phone: (321) 638-1454
> > > > > > Fax: (321) 638-1439 or 1010
> > > > > > Visit our web site at: http://www.fsec.ucf.edu 
> > <http://www.fsec.ucf.edu>
> > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>> 
> > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>
> > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>>
> > > > > >
> > > > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > > > >
> > > > > >
> > > > >
> > > > > --
> > > > > Richard A. Raustad
> > > > > Senior Research Engineer
> > > > > Florida Solar Energy Center
> > > > > University of Central Florida
> > > > > 1679 Clearlake Road
> > > > > Cocoa, FL 32922-5703
> > > > > Phone: (321) 638-1454
> > > > > Fax: (321) 638-1439 or 1010
> > > > > Visit our web site at: http://www.fsec.ucf.edu 
> > <http://www.fsec.ucf.edu> <http://www.fsec.ucf.edu 
> > <http://www.fsec.ucf.edu>>
> > > > >
> > > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > > >
> > > >
> > > >
> > >
> > > --
> > > Richard A. Raustad
> > > Senior Research Engineer
> > > Florida Solar Energy Center
> > > University of Central Florida
> > > 1679 Clearlake Road
> > > Cocoa, FL 32922-5703
> > > Phone: (321) 638-1454
> > > Fax: (321) 638-1439 or 1010
> > > Visit our web site at: http://www.fsec.ucf.edu 
<http://www.fsec.ucf.edu>
> > >
> > > UCF - From Promise to Prominence: Celebrating 40 Years
> > >
> >
> > 
> 
> -- 
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL  32922-5703
> Phone:   (321) 638-1454
> Fax:     (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
> 
> UCF - From Promise to Prominence: Celebrating 40 Years
>




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- Re: [EnergyPlus_Support] Re: Air flow from one zone to another: extraction to return air duct
  - From: Richard Raustad

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