[esp-r] FW: Mysterious zone temperatures

[Matthew Wright]

All,

Is the model constructed in such a way that increased air movement is
reflected in increased air changes through fabric air permeability? 
Does that sort of behaviour have to 'programmed' in, or is it part of the
base algorithms?
Increased air movement would then increase heat losses, so explaining the
missing energy.
Just a thought...

Regards
 
Matt


-----Original Message-----
From: esp-r-bounces at lists.strath.ac.uk
[mailto:esp-r-bounces at lists.strath.ac.uk] On Behalf Of Liam O'Brien
Sent: 10 September 2009 02:56
To: esp-r at lists.strath.ac.uk
Subject: [esp-r] Mysterious zone temperatures

Hi All,

I came across a strange phenomenon that I can't explain and I'm hoping 
someone out there can.  I have a very basic model with two adjacent 
cubic 1000 m^3 zones; one with a large glazing area, the other opaque.  
They are otherwise thermally identical.  I am studying the effect of 
different airflow rates between them. 

I specified airflow in the opr files by having air flow from zone #1 to 
zone #2 and the same quantity going the reverse direction, 
simulataneouly, for mass balance. 

What I would expect is: as the airflow rates approach some high level, 
the zone air temperatures equalize at some temperature that is near the 
average of the two when there is no airflow.

What I got: the temperatures do begin to equalize, but at some level 
that is about 2-3C below expected.  This reprsents a lot of "missing" 
energy.

I re-ran the model for airflow rates between 0 and 360 m^3/s.  The 
unexpected results appear to occur around 30 m^3/s and above.

The same experiment using an airflow network yielded a similar conclusion.

I would be extremely grateful if someone could enlighten me.  Thanks 
very much.

Liam O'Brien
PhD candidate
Concordia University




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