[EnergyPlus_Support] Re: Infiltration

["Jean marais" <jeannieboef@xxxxxxxxx>]

I'm interested in this subject. I once setup manually the air tightness in the following way: 

e.g.
Infiltration of closed exterior windows/doors is set for a relatively tightly sealed building at 0.3 ACH at 50Pa Blower Door. This is achieved by taking the building volume 2057 m³ at 0.3 ACH = 617.1 m³/h = 0.171466 m³/s divided equally over the number of exterior window/door cracks,

i.e. Baseline Building has 119 exterior window/door x4 cracks each (top, bottom, side, side) ï?  crack Air Mass Flow Coefficient When Window or Door Is Closed (kg/s @ 1Pa per m crack) = ((0.171466)/(119x4))/((50)(0.5) ) = 0.00005092852413

where Air Mass Flow Exponent When Window or Door Is Closed (dimensionless) = 0.5

Interior doors are modeled as always closed with (both baseline and design models) the crack Air Mass Flow Coefficient When Window or Door Is Closed (kg/s @ 1Pa per m crack) = (0.024[1])/ (4 cracks x (25)(0.65) ) = 0.000725

[1] Poulsen, P.E. â??Smoke Control Doors Test Reportâ?? Danish Nat Inst for Testing of Materials, Copenhagen (1979)

All edges
Avg Gap Thickness mm = 0.6 mm
Gap Depth = 60 mm
Gap Length = 6.0 m
Flow Rate = 0.024 m³/s

Cracks are not modeled for non-openable interior windows.
Holes are assumed to have Air Mass Flow Coefficient (kg/s @ 1Pa per m crack) = 0.1 and Air Mass Flow Exponent (dimensionless) = 1.0 for free flow without resistance.

....................this was a simple 29 room one story building.

I have not checked the latest from designbuilder for the n50 proceedure and natural ventilation, but am looking forward to in the future.

Jean 


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Jeremiah Crossett  wrote:
>
> Thanks Ned-
> You might check how this feature works when natural ventilation is set to
> calculated and scheduled-- It would make since that when calculated is
> checked the AFN infiltration  objects are used on all external surfaces but
> when scheduled is checked than infiltration is modeled
> ZoneInfiltrationDesignFlowRate..
> *
> *
> *
> *
> *Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions*
> *
> 120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951
> www.phasechange.com
> *
> 
> *
> *
> *
> *
> 
> 
> 
> On Fri, Feb 1, 2013 at 10:40 AM, Edward G. Lyon  wrote:
> 
> > **
> >
> >
> >  Thanks, we have Design Builder in the company, but I don�t use it
> > myself.  When I have some time I�ll check out what they do exactly.****
> >
> > ** **
> >
> > *Ned Lyon, P.E. (MA, WV)**
> > *Staff Consultant ****
> >
> > *SIMPSON GUMPERTZ & HEGER** *
> > 781.907.9000 main
> > 781.907.9350 direct
> > 781.907.9009 fax
> > www.sgh.com****
> >
> >   ****
> >
> > *From:* EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:
> > EnergyPlus_Support@xxxxxxxxxxxxxxx] *On Behalf Of *Jeremiah Crossett
> > *Sent:* Friday, February 01, 2013 1:34 PM
> > *To:* EnergyPlus_Support@xxxxxxxxxxxxxxx
> > *Subject:* Re: [EnergyPlus_Support] Infiltration****
> >
> > ** **
> >
> >   ****
> >
> > I agree with Ned, but also think it is worth mentioning that Design
> > Builder has a simple input from blower door to Energy Plus that might be
> > worth looking into, and I have attached a screen shot of the input. I am
> > not 100% sure how DB applies this to its E+ file generation but assume it
> > uses the ZoneInfiltrationDesignFlowRate Object pasted from another file
> > below. I think there is a better way to do it with airflow network as well.
> > ****
> >
> > ** **
> >
> > Name Infiltration****
> >
> > Zone or ZoneList Name     Zone****
> >
> > Schedule Name       On****
> >
> > Design Flow Rate Calculation Method     Flow/zone****
> >
> > Design Flow Rate    0.018****
> >
> > Flow per Zone Floor Area  ****
> >
> > Flow per Exterior Surface Area     ****
> >
> > Air Changes per Hour        ****
> >
> > Constant Term Coefficient  1****
> >
> > Temperature Term Coefficient     0****
> >
> > Velocity Term Coefficient   0****
> >
> > Velocity Squared Term Coefficient          0****
> >
> > ** **
> >
> > ** **
> >
> > ** **
> >
> > *Jeremiah D. Crossett  | Senior Analyst  |  Phase Change Energy Solutions*
> > ****
> >
> > *120 E. Pritchard St.  | Asheboro, NC 27203  | Mobile 503-688-8951***
> >
> > *www.phasechange.com ***
> >
> >   ****
> >
> > ** **
> >
> > ** **
> >
> > ** **
> >
> > ** **
> >
> > On Fri, Feb 1, 2013 at 10:15 AM, Edward G. Lyon  wrote:***
> > *
> >
> >   ****
> >
> > In my opinion, the answer to your question is very complex.  I am not sure
> > what you mean precisely by 50Pa test.  Usually this means ACH50 (air
> > changes per hour at 50 Pa), but you could have a complete test that reports
> > Coef and Expon for the flow equation Flow = Coef*Pressure^Expon.****
> >
> >  ****
> >
> > In either case there is no short cut way I see to put this data directly
> > into EnergyPlus.****
> >
> >  ****
> >
> > I also think different procedures may apply to different types of
> > buildings.  If you have a small house, and ACH50 result divided by 20
> > (sometimes other factors) is a fair approximation of the infiltration air
> > exchange rate for a small building.  You could define Infiltration as an
> > ACH and juggle the coefficients to give you a better guess for seasonal
> > temperature and wind conditions.  Or you could study the research on ACH50
> > correlations to infiltration and schedule something appropriate for your
> > location.  If you have a commercial building, your test data should be unit
> > area based and you would use Infiltration with a surface area calculation.
> > ****
> >
> >  ****
> >
> > Infiltration in EnergyPlus has a sophisticated set of input parameters
> > intended to vary infiltration by site conditions, and I have done a lot of
> > whole building testing.  Perhaps others can provide a good reference for
> > integrating measured data into the energy model, but I have not seen it.  I
> > think there may a way to approximate the pressure from the temperature and
> > wind in order to recalculate coefficients for Infiltration in EnergyPlus.
> > Perhaps I need to study this in more depth myself.****
> >
> >  ****
> >
> > From my testing work I also know that not all parts of the building leak
> > the same.  There may be different results for different zones (roof to wall
> > edges leak more than field of wall).  This is likely to influence some
> > zones more than others.  Also a very leaky roof above very tight walls will
> > give you a very leaky test result, but the actual infiltration affecting
> > energy could be much less.      ****
> >
> >  ****
> >
> > For a recent model that looked at temperature conditions and not energy, I
> > was able to use an air flow network.  The equations there are more easily
> > adaptable to the results of a building blower door test and the analysis
> > automatically calculates pressures based on wind and temperature.  This can
> > get complicated for larger buildings, and may not work with other fans in a
> > mechanical system.****
> >
> >  ****
> >
> > Now it is not my intention to offend all the serious and dedicated energy
> > modelers out there who put infiltration into their models.  I just don�t
> > see how it is currently much more than a guess or accepted practice, and I
> > would be interested in any available information on correlating test data
> > to models.  I get asked that question a lot, and each energy model
> > calculates infiltration in a slightly different way. ****
> >
> >  ****
> >
> > *Ned Lyon, P.E. (MA, WV)
> > *Staff Consultant ****
> >
> > *SIMPSON GUMPERTZ & HEGER** *
> > 781.907.9000 main
> > 781.907.9350 direct
> > 781.907.9009 fax
> > www.sgh.com****
> >
> >   ****
> >
> > *From:* EnergyPlus_Support@xxxxxxxxxxxxxxx [mailto:
> > EnergyPlus_Support@xxxxxxxxxxxxxxx] *On Behalf Of *FrancescoP
> > *Sent:* Friday, February 01, 2013 12:09 PM
> > *To:* EnergyPlus_Support@xxxxxxxxxxxxxxx
> > *Subject:* [EnergyPlus_Support] Infiltration****
> >
> >  ****
> >
> >   ****
> >
> > I wonder what the best ways to model infiltration in these two cases are:
> > 1. you know the result of the blower door test (50Pa)
> > 2. no blower door test was made but you know how the building was built
> > Any idea?
> > With Regards****
> >
> > ** **
> >
> > ****
> >
> >  
> >
>




------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the Documentation link and press the "search" button.
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/