[EnergyPlus_Support] Re: Can Airflow Network simulate stack effect?

["Wonjun" <lesthesia@xxxxxxxxxxx>]

Thanks for your valuable answer, Lixing. 

Even though stack effect has been validated with ASHRAE analytic solution, what is the limitation in case of simulate DSF cavity flow?
Is it just not accurate in that AFN can't simulate the temperature stratificaiton, or is there other reason exist? 

When I made a DSF building with the AFN algorithm, the result seemed to pretty well matched from air physical view(Comparing airflow rate and velocity of lower part opening and upper part opening). 

I have read the simulate DSFs with AFN algorithm published in ASHRAE Transactions.

For example 
http://www.bwk.tue.nl/bps/hensen/publications/02_ashrae_dskin.pdf

I wanna know the exact limitation of the AFN algorithm when I use it to simulate DSF cavity flow. 
 
Many more thanks in advance. 
 

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> The stack effect comparison was performed to compare analytical results
> provided by ASHRAE research project 1052. Here is a link to get a pdf file:
> http://apps1.eere.energy.gov/buildings/energyplus/pdfs/energyplus_ashrae_105
> 2rp_envelope.pdf. Section 2.12 "Test Infiltration-2, Stack Effect" provides
> detailed description.
> 
> The algorithm is not designed to simulate the DSF cavity airflows. 
> 
> Thanks.
> 
> Lixing
> 
> -----Original Message-----
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Wonjun
> Sent: Monday, October 18, 2010 9:43 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Can Airflow Network simulate stack effect?
> 
> I have already read I/O reference and engineering reference related to AFN. 
> In engineering reference which states AFN algorithm, it states that this
> algorithm considers the pressure differece by density and height. 
> But I don't know whether this algorithm can simulate the ventilation by
> stack effect. (For example double skin facades' cavity flow)
> I know this algorithm assumes that the air is perfectly mixed and has
> uniform property. 
> Then, how AFN algorithm can describe the temperature stratification? 
> Is there a validation document related to AFN's stack effect limitation?
> (I.e., when you try to simulate a zone higher than specific height, the
> results will not accrate. This kind of document) 
> 
> Please give me a help. 
> Many thanks in advance.
>  
> 
>  
>  
> 
> 
> 
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