[esp-r] Re: air quality assessment for room with natural ventilation

[Geissler Achim]

... I seem to remember that Comis was capable. However, one needed to define the "Stack" in the one-sided-ventilated-zone (temperature difference over the height of the zone). And, one could define two different external nodes for the top / bottom opening to the outside with two different sets of Cp-values ...
Maybe stacking a few zones for one actual space and then having inlet and outlet in different stacked zones could help. For this type of model I am always a bit queasy in regard to long wave radiation ... Gunter did mention a cooled ceiling ...
Regards,
Achim

> -----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, November 07, 2007 12:29 PM
> To: esp-r at lists.strath.ac.uk
> Subject: [esp-r] Re: air quality assessment for room with natural
> ventilation
> 
> I think the question is: does ESP-r have the capability to model bi-
> directional airflow through an open window into a zone that is
> substantially sealed from other zones in the building.  A common question
> and the answer (short of invoking the CFD domain) is no - the bi-
> directional flow component was originally developed to model tall vertical
> openings, typically doors, between zones, with bouyancy driven airflows in
> either direction.  It does not take account of wind turbulence effects
> that will drive bi-directional airflow at an open window, which is what is
> missing for this application.  Modelling as two orifices won't help - they
> will both see the same external pressure node.
> 
> This topic has been researched (I co-authored a paper on this in the '70s)
> but to my knowledge no-one has coded such functionality into any zonal
> dynamic modelling tool ... but I might be mistaken ...
> 
> Jeremy
> 
> -----Original Message-----
> From: esp-r-bounces at lists.strath.ac.uk [mailto:esp-r-
> bounces at lists.strath.ac.uk] On Behalf Of Aizaz Samuel
> Sent: 07 November 2007 10:25
> To: Pueltz, Gunter
> Cc: esp-r at lists.strath.ac.uk
> Subject: [esp-r] Re: air quality assessment for room with natural
> ventilation
> 
> Contaminant modelling works with bi-directional flow components just as
> with other components and you probably will end up with more CO2 going out
> of the zone as coming into it provided there are local CO2 sources
> (metabolic rates
> maybe) defined within the zone. I have never made a model with bi-
> directional components though and would fall back on Jon's recommendation
> if it does not work.
> 
> There is no provision yet to show the mass flow of contaminant along each
> flow path because only concentration for each node is stored in the
> results library. It should be possible to obtain this information by post
> processing node concentrations and air flow rates
> 
> -Aizaz
> 
> On Wednesday 07 November 2007 07:06, Jon Hand wrote:
> > A bi-directional component might be replace by two common orifice
> > components (suitably placed to represent the upper and lower portion
> > of the window).
> > That should allow the CO2 to 'see' the flow in.
> >
> > Whether the CO2 bookkeepping could be revised to allow it to track
> > both paths of a bi-directional component is something Aizaz might
> > advise on.
> >
> > -Jon
> >
> >
> > -----Original Message-----
> > From: Pueltz, Gunter [mailto:Gunter.Pueltz at MuellerBBM.de]
> > Sent: Wed 11/7/2007 6:38 AM
> > To: 'esp-r at lists.strath.ac.uk'
> > Cc: Aizaz Samuel; Jon Hand
> > Subject: air quality assessment for room with natural ventilation
> >
> > Dear ESP-r developers,
> >
> > currently I have a simulation job for an office building, which shows
> > only natural ventilation (NO mechanical ventilation) by openable windows.
> > In Summer the rooms are cooled by chilled ceilings.
> >
> > Now my client wants infos about the indoor air quality, which can be
> > obtained by the window ventilation.
> > I do know, that ESP-r shows the ability to calculate CO2-concentrations.
> > This is a good facility to assess indoor air quality, as CO2 is
> > representing air quality very well.
> > But my last knowledge of this contaminant calculations in ESP-r was,
> > that for a flow component with BI-DIRECTIONAL air flow (typical for an
> > open
> > window)
> > only the net-flow is taken into account for the CO2-balance in ESP-r.
> > The net-flow of an open window of one single room always is zero - so
> > this approach do not work for a room with single-sided window
> > ventilation.
> > Or - in other words - the reduction of CO2-concentration in a room by
> > a bidirectional airflow through an open window can not be calculated so
> far.
> >
> > Currently I am using ESP-r, version 11.3: Does this (or a future ?)
> > version show the ability to assess indoor air quality in rooms with
> > natural ventilation (which means BI-DIRECTIONAL air flow must be taken
> > into account completely) ?
> >
> > Best regards,
> > 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
> >
> > HRB München 86143
> > Geschäftsführer: Bernd Grözinger, Dr. Edwin Schorer, Norbert Suritsch
> 
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