[EnergyPlus_Support] Re: Conversion of data from Blower door to Infiltration rates

["mark.dewsbury@xxxxxxxxx" <mark.dewsbury@xxxxxxxxxxx>]

Dear Dave,
Thanks for your prompt reply. 
This is purely for use as input values for Zone built fabric infiltration/exfiltration. 

The infiltration rate, in air changes per hour, is specified as A + B*v, where v is the wind speed in m/s. 

This comes from the recognition of differential infiltration rates relative to wind pressure. A bit like the blower door test: as you change the pressure differential the graph is not always linear. This creates a situation where an A & B value is calculated. 

However, your reply was to the point and I think I just need to sit down now and do some maths. 

Regards
mark Dewsbury   


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, David Lorenzetti <DMLorenzetti@...> wrote:
>
> Mark,
> 
> One strategy might be to convert your blower-door-induced pressure to
> an effective wind speed, set {A} to zero, and calculate the required
> {B}.  I wrote a post a few days ago that will suggest some details for
> how to do this.
> 
> I don't know what that {A} parameter is supposed to represent in the
> physical world (maybe mechanical devices that are small enough they
> don't dominate wind effects, but that's generally considered
> ventilation not infiltration).  The main reason infiltration at zero
> wind speed will be nonzero is indoor-outdoor temperature differences.
> But (1) these are not constant; and (2) the generally-accepted
> approach to forming a simple model along these lines is to add
> temperature and wind speed effects in quadrature-- something more like
> C * sqrt( A*dT + B*V^2 )
> 
> You can search on "Sherman-Grimsrud infiltration model" and find more
> on this.  Here's a report that may have everything you need:
> http://gundog.lbl.gov/dirpubs/10852_ShermanGrimsrud.pdf
> 
> -Dave
> 
> > I have been using a blower door system for the last couple of years, as a cost preference to Tracer gas testing.
> > I am now back on the empirical validation wagon and need some pointers or advice on converting Blower Door results.
> > The Australian HER software has an infiltration formula which is A + (B x V), where A = constant, B = a value based on wind speed & V = wind speed.
>




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