[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [EnergyPlus_Support] Re: Air flow from one zone to another: extraction to return air duct
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>, 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>, 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>>>
> > > > >
> > > > > 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
------------------------------------
The primary EnergyPlus web site is found at:
http://www.energyplus.gov
The group web site is:
http://groups.yahoo.com/group/EnergyPlus_Support/
Attachments are not allowed -- please post any files to the appropriate folder in the Files area of the Support Web Site.
EnergyPlus Documentation is searchable. Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/EnergyPlus_Support/
<*> Your email settings:
Individual Email | Traditional
<*> To change settings online go to:
http://groups.yahoo.com/group/EnergyPlus_Support/join
(Yahoo! ID required)
<*> To change settings via email:
mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx
mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx
<*> To unsubscribe from this group, send an email to:
EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/