[esp-r] Re: Bi-directional air flow component for VERTICAL ai r exchange
Pueltz, Gunter
Gunter.Pueltz at MuellerBBM.de
Wed Sep 13 10:54:13 BST 2006
If CFD is used for resolving the vertical air flow exchange,
the CFD domain of ESP -r must be able to extend over several
stacked zones (not only one zone) .... ?
And how to match the problem with skylights opening towards
outside ? I assume using CFD for modelling the outside/ambient
air is no so easy, or ... ?
I only can reaffirm the needness of an air flow component for
vertical air flow exchange as a part of ZONAL air flow network !
Gunter
> -----Original Message-----
> From: esp-r-bounces at lists.strath.ac.uk
> [mailto:esp-r-bounces at lists.strath.ac.uk]On Behalf Of Jeremy Cockroft
> Sent: Wednesday, September 13, 2006 11:42 AM
> To: esp-r at lists.strath.ac.uk
> Subject: [esp-r] Re: Bi-directional air flow component for VERTICAL
> airex change
>
>
> As already stated by other posters, the bi-directional flow
> component models the physics of vertical openings, and has no
> meaning when applied to a horizontal opening. Maybe the
> complexity of air flows within atria and the like would
> justify the use of the CFD domain within ESP-r - perhaps that
> is where development activity to address this class of
> problem should be applied.
> Jeremy Cockroft
> University of Strathclyde
>
> -----Original Message-----
> From: esp-r-bounces at lists.strath.ac.uk
> [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Pueltz, Gunter
> Sent: 13 September 2006 10:02
> To: esp-r at lists.strath.ac.uk
> Subject: [esp-r] Re: Bi-directional air flow component for
> VERTICAL airex change
>
> Very interesting discussion about the vertical air exchange
> of stacked zones !
>
> 1) First I want to affirm Jan´s statement, that a
> bi-directional air flow component should NOT be used for
> vertical air exchange ! The bi-directional door element has
> been developed for verical elements like doors or windows,
> thus the results for vertical air exchange (i.e. skylights)
> would be absolutely meaningless (or even wrong) !!!!
>
> 2) The interesting discussion shows however the strong
> requirement/needness of a bi-directional air-flow component
> for VERTICAL air flow exchange, which always takes place in
> an atrium or in a large open space over several floors ...
> The physical phenomena, which drives the vertical air flow
> exchange in such spaces are also well known:
>
> a) thermal instable stratification (means cold air above warm
> air), which initiates the so called
> "Raleigh-Bernard-convection" (= small eddys at the interface
> between upper cold and lower warm air); the intensity of this
> vertical air exchange rate is depending on the difference of
> air temperature at the upper/lower air flow node ...
>
> b) boundary layers at vertical facades, which initiate an
> upward(warm) or
> downward(cold) air
> flow within the boundary layer; the intensity of this
> vertical air exchange rate is depending on the difference
> between node air temperature and the internal surface
> temperature of the adjacent surfaces ...
>
>
> It would be a great enhancement of ESP -r, if an air flow
> component would be
> developed for
> the vertical air flow exchange, based on the two main driving physical
> phenomena listed above.
>
> Gunter
>
> --
> Dr. Gunter Pültz
>
> Müller-BBM GmbH
> Robert-Koch-Straße 11
> 82152 Planegg
> Telefon +49 (0)89 85602 - 336
> Telefax +49 (0)89 85602 - 111
> http://www.MuellerBBM.de
>
> > -----Original Message-----
> > From: esp-r-bounces at lists.strath.ac.uk
> > [mailto:esp-r-bounces at lists.strath.ac.uk]On Behalf Of Hensen, J.L.M.
> > Sent: Wednesday, September 13, 2006 10:05 AM
> > To: esp-r at lists.strath.ac.uk
> > Subject: [esp-r] Re: 1) Bi-directional Doors in Horiontal
> > surfaces2)Dummy-nodescheme
> >
> >
> >
> > In my opinion, you shouldn't use a bi-directional flow large
> > opening in
> > a horizontal position. It is totally out of the theoretical
> > scope of the
> > model. The results are more than likely to be meaningless.
> > You can use multiple one-way flow openings instead.
> >
> > Jan
> >
> > -----Original Message-----
> > From: esp-r-bounces at lists.strath.ac.uk
> > [mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Oliver Bucks
> > Sent: Wednesday, September 13, 2006 9:56 AM
> > To: esp-r at lists.strath.ac.uk
> > Subject: [esp-r] Re: 1) Bi-directional Doors in Horiontal
> > surfaces2)Dummy-nodescheme
> >
> > Jake,
> >
> > I'm not an expert, but I think I have overcome this problem when
> > simulating big
> > trombe walls. The delta H should be precisely that between
> > the nodes....
> > eg, a
> > horizontal skylight with an exterior node @ 0.5m above the
> > skylight, and
> > the
> > zonal node @ 1.5m below the skylight, the delta H would be 2m and
> > -2m.....
> >
> > I might be wrong though
> >
> > Olli Bucks
> >
> > ----- Original Message -----
> > From: "Jake Zwart" <jake.zwart at sympatico.ca>
> > To: <esp-r at lists.strath.ac.uk>
> > Sent: Tuesday, September 12, 2006 9:10 PM
> > Subject: [esp-r] 1) Bi-directional Doors in Horiontal surfaces
> > 2)Dummy-nodescheme
> >
> >
> > > Two questions:
> > >
> > > 1) I have heard of a trick using bi-directional door components in
> > horiontal
> > > surfaces. In fact this is mentioned in the FAQ regarding atriums.
> > However
> > > the input data for using a bi-directional door assumes it is in a
> > vertical
> > > surface because it asks for the height difference between
> > the base of
> > the
> > > door and the center of both zones which it seperates. I looked up
> > Hensen's
> > > thesis and the door component seems to have these
> assumptions built
> > in. So,
> > > how can I implement a bi-directional door component between
> > vertically
> > > stacked zones in my atrium?
> > >
> > > 2) I am using the dummy node scheme for my window controls
> > as follows:
> > >
> > > I am implementing a control strategy for opening and
> closing window
> > with two
> > > separate controls in series. The controls are:
> > >
> > > 1. When the indoor temperature exceeds a set temperature,
> > say 20 C the
> > > windows will open.
> > > 2. When the ambient temperature exceeds the indoor
> temperature, the
> > dummy
> > > windows
> > > will close to prevent convective heating.
> > >
> > > When I run the simulation, the dummy nodes stays at a
> constant 20?C
> > (the
> > > temperature which I set the node to for the start of the run).
> > > Interestingly, although the dummy nodes stayed at a constant 20 C,
> > interior
> > > temperatures did drop below 20 C as a result of (what looks like)
> > > ventilation.
> > >
> > > Now, it seems to me that the dummy node should be a
> calculated node
> > and not
> > > following some other node temperature. Say for example
> > that the dummy
> > > follows the ambient, then, when the dummy window is open but the
> > window
> > > between the dummy to outside is closed, the zone will
> still interact
> > with
> > > outside. Now say that the dummy follows the interior node/zone
> > temperature.
> > > In this case when both windows are open, all incoming
> > ventilation air
> > will
> > > be no help since it will be at the interior node/one temperature
> > already.
> > >
> > > How can I ensure that the dummy node is a calculated
> temperature and
> > that
> > > the dummy node scheme will work properly?
> > >
> > > Thanks,
> > >
> > > Andrew Zwart
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: esp-r-bounces at lists.strath.ac.uk
> > > [mailto:esp-r-bounces at lists.strath.ac.uk]On Behalf Of Jon Hand
> > > Sent: Saturday, 09 September, 2006 11:58
> > > To: kostas ordoumpozanis
> > > Cc: esp-r at lists.strath.ac.uk
> > > Subject: [esp-r] Re: tutorial help
> > >
> > >
> > >
> > > The best current tutorial for ESP-r is the ESP-r cookbook
> > > which is available on the ESRU web page publications or
> > > as part of the ESP-r source distribution.
> > >
> > > The browsing function is somewhat old and is probably
> > > trying to invoke netscape. There are quite a few useful
> > > resources on the ESRU web page which can be invoked
> > > manually via your favorite browser.
> > >
> > > -ESRU
> > >
> > >
> > > -----Original Message-----
> > > From: esp-r-bounces at lists.strath.ac.uk on behalf of kostas
> > ordoumpozanis
> > > Sent: Sat 9/9/2006 12:10 PM
> > > To: esp-r at strath.ac.uk
> > > Subject: [esp-r] tutorial help
> > >
> > > Hi. I am trying to launch the tutorial button on project
> manager and
> > after
> > > it shows the message "Starting Browsing..." it does nothing. Any
> > answer to
> > > that.
> > >
> > > Thanks
> > > Ordoumpozanis Kostas
> > > Greece
> > >
> > >
> > >
> > > _______________________________________________
> > > esp-r mailing list
> > > esp-r at lists.strath.ac.uk
> > > http://lists.strath.ac.uk/mailman/listinfo/esp-r
> > >
> >
> >
> > --------------------------------------------------------------
> > ----------
> > --------
> >
> >
> > > _______________________________________________
> > > esp-r mailing list
> > > esp-r at lists.strath.ac.uk
> > > http://lists.strath.ac.uk/mailman/listinfo/esp-r
> >
> >
> > --------------------------------------------------------------
> > ----------
> > --------
> >
> >
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> >
> >
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>
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