[esp-r] Re: storage of humidity within massiv components ?

[Abdul Rahim Bin Mahmood]

Hi,

ESP-r does allow a simple steady-state analysis of condensation risk based on 
vapour diffusion. In addition, Dr Abdul Nakhi put in the capability to 
include absorption/desorption as part of his PhD work (see 
www.strath.ac.uk/Documents/PhD/nakhi_thesis.pdf). However, this needs further 
work. Implementing improved moisture transport and storage capability in 
ESP-r will be part of my PhD study I hope to progress on.

Abdul Mahmood



On Thursday 29 November 2007 13:50:20 Ferguson, Alex wrote:
> Hi Jake,
>
> Every simulation tool has strengths and weaknesses. ESP-r's treatment of
> moisture diffusion (or lack there-of) is a known deficiency. It's an area
> of interest for us, mostly because we cannot accurately model night-time
> natural ventilation and free cooling strategies without computing the
> latent load resulting when moisture from humid air is absorbed in the
> building structure and furnishings. We have some funding to improve this
> aspect of ESP-r, but the work is presently on hold while we focus on other
> priorities.
>
> As I'm sure both you and Professor Straube can attest to, the validity of a
> model's predictions depends as much on how well the user understands the
> underlying algorithms as on the model's theoretical vigour. Even
> comparatively simple tools with well-known flaws (for example, HOT2000 and
> DOE2.1) can be applied accurately as long as their limits are respected.
> And that's perhaps the biggest challenge to using ESP-r --- its limitations
> are not well documented and often difficult to discern.
>
> A few years ago, the US DOE, ESRU and SEL produced a fairly comprehensive
> report describing the capabilities of prominent building energy simulation
> programs. WUFI didn't make the list, probably because in 2005 WUFI (then
> WUFI-ORNL/IBP) was focused primarly on mosture transport and its energy
> modelling capabilities are a fairly recent addition.
>
> http://www.eere.energy.gov/buildings/tools_directory/pdfs/contrasting_the_c
>apabilities_of_building_energy_performance_simulation_programs_v1.0.pdf
>
> - Alex
>
>
> -----Original Message-----
> From: Jake Zwart [mailto:jake.zwart at sympatico.ca]
> Sent: Thursday, November 29, 2007 07:50
> To: Ferguson, Alex
> Subject: FW: [esp-r] storage of humidity within massiv components ?
>
> Hi Alex:
>
> I thought I would forward this email on to you.  If esp-r has one of the
> better whole building simulation engines, and people struggle with it, does
> that say something about the other simulators?
>
> I am sort of passing this on, in case it may a topic of interest for your
> research should you try for an advanced degree.  It may also be a of
> interest should proper hygric modeling be incorporated into esp-r.  I
> suppose to do something like that may mean a completely new simulation
> engine would be developed and the two would both be operational, with the
> user selecting which one.
>
> I know that John Straube is very active in moisture transport analysis in
> buildings and the potential harmful effects of a vapour barrier depending
> upon the climate.  Research in this area, especially if it can be
> incorporated into building simulation tools used by the government would
> definitely be useful, and may even allow for an easily accessible
> engineered alternative to vapour barriers, ultimately leading to changes in
> the code regarding vapour barriers.  If this line of research does interest
> you, you might consider John Straube as a supervisor, or co-supervisor.  As
> co-supervisor, you might not even have to move.
>
> I took a look at the WUFI web site and it looks good but TRYNSIS type
> prices.  I did not see any indication of plant components.  There is a free
> educational and non commercial version though.
>
> Jake
>
> -----Original Message-----
> From: John Straube [mailto:jfstraub at civmail.uwaterloo.ca]
> Sent: Wednesday, 28 November, 2007 22:18
> To: jake.zwart at sympatico.ca
> Cc: 'Pueltz, Gunter'; 'John Straube'
> Subject: Re: [esp-r] storage of humidity within massiv components ?
>
>
> Hi there Jake
> esp-r does not handle moisture well. We have struggled even with the
> energy. I have modelled buildings with earth plastered strawbales and
> compared them to field measurements using WUFI with very good results.
> WUFI-Plus is a new whole building program that properly accounts for
> thermal mass, hygric mass, and ventilation energy, moisture and even CO2.
> This is what I would consider.
> The good news for Guenter is that this program is developed and supported
> close to their home at the Fruanhofer Insitut fuer Bauphsik in Holzkirchen.
> Checkout www.wufi.de
>
> Jake Zwart wrote:
> > Hi Gunter,
> >
> > I have been told that esp-r does not model moisture storage in walls
> > which is an essential element of moisture calculation.  Not sure about
> > the
>
> vapour
>
> > diffusion part.
> >
> > I have attached two papers that talk about moisture modeling in walls.  I
> > have tried the simpler steady state method within a spreadsheet and it is
> > quite easily implemented.  The other paper offers about a 5 year old
>
> review
>
> > of simulation packages that may do the modeling that you require.
> >
> > I find the web site www.balancedsolutions.com quite useful for research
> > in this area.
> >
> > I have cced the author of the papers, in case you have any direct
>
> questions.
>
> > I wonder if there has been any discussion about implementing moisture
> > transport and storage within walls in esp-r and what the interest would
>
> be.
>
> > I think it would be quite useful.
> >
> > Jake Zwart
> >
> > -----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: Monday, 26 November, 2007 10:42
> > To: 'esp-r at lists.strath.ac.uk'
> > Subject: [esp-r] storage of humidity within massiv components ?
> >
> >
> > Dear ESRUs,
> >
> > I have to simulate historic rooms with a bit humid walls by ESP -r.
> > Concerning humidity WITHIN the massiv components (not only at the
> > internal surface) following questions:
> >
> > 1) Does ESP -r calculate the humidification + de-humidification of walls
> > resp. the storage of humidity in the walls ?
> > In the material database a vapour resistivity is defined for each
> > material ....
> > But does ESP-r model vapour diffusion within a multi-layer component ?
> >
> > 2) If there exists a humidity source - e.g. in the ground (groundwater or
> > rain water, which raises upwards into the walls of my rooms) - how can
>
> such
>
> > a humidity source be implemented WITHIN a multi-layer-component (e.g. a
> > wall) ?
> >
> > Any idea or comment appreciated.
> >
> > 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
> >
> > _______________________________________________
> > esp-r mailing list
> > esp-r at lists.strath.ac.uk
> > http://lists.strath.ac.uk/mailman/listinfo/esp-r
>
> --
> Dr John Straube, P.Eng.
> Associate Professor
> Dept of Civil Engineering & School of Architecture
> University of Waterloo
> Waterloo, ON Canada
>
>
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