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[EnergyPlus_Support] Re: Zone components of a 2-pipe system?
Another question, to add to the previous:
- The Compact HVAC approach doesn't let us define both a Zone:VAV and
a FanCoil? (I get errors about duplicate Zone sizing objects...)
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "anarui.oliveira"
<anarui.oliveira@...> wrote:
>
> Thanks a lot.
>
> The Central AHU has a heat recovery component, which receives the
> return airflow from more than 1 zone, so I think I should keep the
> two levels of the heating/cooling process?...as opposed to letting
> the fan-coils addressing the full thermal load?...
> In this case, it appears it wouldn't actually be easier to treat
the
> heat recovery by "manual" post-processing?...Or are there any known
> downsides to this two-level approach?
>
> At the moment, is there any approach in E+ that would accurately
> mimic the system I described? I mean, could I actually (with nore
or
> less "manual work"), set up both a heating and a cooling coil to
act
> on the supply air, at zone level, setting both coils operation to
> depend on the zone thermostat (at the moment, I don't really need
> many details on this, I would just like to know the possibilities)?
>
> Again, thanks a lot,
> Ana Rui.
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
> <mjwitte@> wrote:
> >
> > If I am understanding the system correctly, the simplest approach
> would be to
> > use the 4-pipe fan coil with mutually exclusive schedules for the
> heating and
> > cooling coils. However, do not set the inlet conditions to be
from
> the central
> > ahu, simply let the fancoil unit carry the entire load.
> >
> > It is not clear to me whether it matters that the heaitng/cooling
> be modeled in
> > two parts. If it does matter, then I would still use the 4-pipe
> fan coil, but
> > with no outside air. And then describe a constant volume air
loop
> which
> > delivers the partially conditioned outside air using a direct air
> terminal unit
> > in each zone. If the direct air unit is listed with heating and
> cooling
> > priority 1, then the fan coil will pick up any remaining load.
> >
> > Mike
> >
> >
> > On 26 Jan 2008 at 17:03, anarui.oliveira wrote:
> >
> > > Hello, all.
> > >
> > > I'm having a hard time to figure out the best options to model
a
> > > specific 2-pipe HVAC configuration...
> > >
> > > Any ideas about which could be the simplest way to approximate
> the
> > > zone level model of a 2-pipe (constant volume) system with:
> > > - an AHU that delivers 100% OA at inermediate heated/cooled
> > > temperatures (18/27 ºC) to the zone level,
> > > - where a battery with either hot or chilled water coil
(mutually
> > > exclusive at any given moment, and necessarily in the same
> operation
> > > regime - heating or cooling - serving the central AHU) meets
the
> > > additional load (when needed),
> > > - raising/decreasing the air temperature of the supply air loop
> to
> > > design Temperatures of 35ºC(heating) or 16ºC (cooling), to meet
> Room
> > > Air setpoint conditions according to a 20-25ºC thermostat?
> > >
> > > The "Single Duct:Const Volume: Reheat" and "Single Duct:Const
> Volume:4
> > > pipe" don't quite seem to reproduce this behaviour?...
> > >
> > > No recirculating or induced air from the room actually happens
in
> the
> > > real situation (the zone level re-conditioning is performed
> directly
> > > and uniquely in the air supplied by the AHU, and then delivered
> to the
> > > room, where the mixed model should take care of the rest)...
> > > ...but perhaps, in terms of global thermal loads and energetic
> > > analysis, it wouldn't be too far fetched to use
> > > - "Single Duct:Const Volume:4 pipe"
> > > or
> > > - "direct air" and "fan coil: 4 pipe"
> > > with mutually exclusive availability schedules for the coils
and
> > > design air inlet temperatures equal to the setpoints of AHU
> supply
> > > air?...
> > > ... the main differences between these options being?...
> > >
> > > Better options?...
> > >
> > > Thanks in advance,
> > > Ana Rui.
> > >
> > >
> > >
> > > 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
> > >
> > >
> > >
> > >
> > >
> >
> >
> > ========================================================
> > Michael J. Witte, GARD Analytics, Inc.
> > EnergyPlus Testing and Support
> > EnergyPlus-Support@
> >
>
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