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[EnergyPlus_Support] Re: (Still) airflow balances!
Thank you!
Ana.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Fred Buhl <wfbuhl@...>
wrote:
>
> So my suggestion is:
>
> Zone 1 is served by the air loop and contains the exhaust fan.
This fan
> exhausts
> the air to the outside. The air flow will now be correct for the
heat
> recovery device.
> Zone 2 is unconditioned (is not served by the air loop).
> To account for the exhaust fan really being in Zone 2 and inducing
air
> from Zone
> 1, there should be Mixing object with Zone 2 as the receiving
zone and
> Zone 1
> as the source zone. The flow rate should match the exhaust flow
rate.
> There is
> no need to balance the air from the Mixing object entering Zone 2 -
the
> zone will not
> explode. EnergyPlus does not concern itself with air mass balance
from
> inputs
> such as Mixing, Infiltration, Ventilation. These objects simply
generate
> heat gains or losses
> for the zone energy balance. The real Zone 2 will exhaust the
induced
> air, but we don't
> have to do that in EnergyPlus.
>
> Fred Buhl
>
> Fred Buhl wrote:
> > Thanks Ana; that seems clear - now let me think about it.
> >
> > Fred Buhl
> >
> > anarui.oliveira wrote:
> >
> >> Zone 1 gets its supply air from a CAV central system with heat
> >> recovery.
> >> Part of the airflow supplied to Zone 1 is collected again and
> >> becomes return airflow, passing through the central heat
exchanger
> >> before being discarded. The remaining airflow is supposed to
pass to
> >> the adjacent Zone 2 simply by pressure difference.
> >> In Zone 2 there is just an exhaust fan (in the project), which
keeps
> >> this zone in depression and forces air renovation.
> >>
> >> Thank you for the patience,
> >> Ana.
> >>
> >> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Fred Buhl <wfbuhl@>
> >> wrote:
> >>
> >>
> >>> Ana,
> >>>
> >>> I guess we don't understand what you are trying to simulate.
You
> >>>
> >>>
> >> have 2
> >>
> >>
> >>> zones,
> >>> one of which gets supply air. Just tell us what happens to
this
> >>>
> >>>
> >> air after it
> >>
> >>
> >>> is supplied to the 1st zone. Don't explain it in terms of
> >>>
> >>>
> >> EnergyPlus,
> >>
> >>
> >>> just tell us
> >>> what you actually want to happen. Are there any real exhaust
fans,
> >>>
> >>>
> >> or
> >>
> >>
> >>> did they get
> >>> introduced as an attempt to model the actual situation? Just
> >>>
> >>>
> >> explain
> >>
> >>
> >>> what the system
> >>> is that you are attempting to model (maybe you did this
already,
> >>>
> >>>
> >> but
> >>
> >>
> >>> please do it again).
> >>>
> >>> Fred Buhl
> >>>
> >>> anarui.oliveira wrote:
> >>>
> >>>
> >>>> Thank you all for your previous answers, and please tolerate
my
> >>>> insistence...
> >>>> I see your point about balancing airflows in the source zone,
> >>>>
> >>>>
> >> and I
> >>
> >>
> >>>> think I've got that covered.
> >>>>
> >>>> ...But, returning to a simple example of 2 zones:
> >>>> - one conditioned (Zone 1), with forced supply air (which can
be
> >>>> modelled by E+ system and zone level objects)
> >>>> - and another unconditioned (Zone 2), which:
> >>>> - receives some airflow by depression from the conditioned
> >>>>
> >>>>
> >> zone
> >>
> >>
> >>>> (here I would use a Mixing object(source Zone 1, target Zone
2),
> >>>>
> >>>>
> >> and
> >>
> >>
> >>>> an exhaust fan in Zone 1 (a plain E+ Exhaust fan, no tricks),
> >>>>
> >>>>
> >> just
> >>
> >>
> >>>> to make sure that the source zone also feels the effect of
> >>>>
> >>>>
> >> losing
> >>
> >>
> >>>> that amount of conditioned air)
> >>>> - but then in the unconditioned zone, the HVAC project
says
> >>>>
> >>>>
> >> there
> >>
> >>
> >>>> will also be a regular, forced exhaust airflow (although
there
> >>>>
> >>>>
> >> is no
> >>
> >>
> >>>> mechanical air supply directly to this zone), and it is this
> >>>>
> >>>>
> >> part,
> >>
> >>
> >>>> this exhaust... this balance at the unconditioned zone (which
is
> >>>>
> >>>>
> >> the
> >>
> >>
> >>>> target zone for the mixing object), that I don't quite see
how
> >>>>
> >>>>
> >> to
> >>
> >>
> >>>> implement...
> >>>> - and should I care?... It's not very clear to me, but I
> >>>>
> >>>>
> >> seems
> >>
> >>
> >>>> that if I do force the exhaust of that amount of air, the
> >>>> unconditioned zone will continuosly lose some its partially
> >>>> conditioned air (energy), at the same time as it receives new
> >>>>
> >>>>
> >> air
> >>
> >>
> >>>> from the adjacent zone, while if I don't balance it, it seems
it
> >>>> continuosly accumulates warm air and only loses heat through
the
> >>>> envelope?...
> >>>>
> >>>> Sorry, I have the feeling I'm not making myself very clear,
> >>>>
> >>>>
> >> but...
> >>
> >>
> >>>> ... again, any additional hint would be greatly appreciated!
> >>>>
> >>>> Ana.
> >>>>
> >>>>
> >>>> ------------------------------------
> >>>>
> >>>> 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
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>
> >> ------------------------------------
> >>
> >> 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
> >>
> >>
> >>
> >>
> >>
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> > ------------------------------------
> >
> > 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
> >
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
------------------------------------
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