Re: [EnergyPlus_Support] Re: Greenhouse airflow simulation#2

[Lixing Gu <gu@xxxxxxxxxxxx>]

Marzia:

When I looked at testing results in July (run period specified by the input) 
using Chicago weather, I found 4 windows with H_6339 are not open, because 
the zone 6339 temperature is higher than outdoors. I also found 4 windows 
with H_6346_10003 close and open based on the temperature differences 
between zone and outdoors. As you know, the window opening conditions using 
the temperature control are 1) the zone temperature is higher than outdoors, 
and 2) the zone temperature is above the vent temperature. Therefore, if you 
run annual simulation, when the zone 6339 temperature is above outdoors, you 
should see window open sometimes.

If you define a partition wall twice, the airflow will be a sum against real 
building configuration. Anyway, your expectation should be within the 
program capabilities.

Lixing

----- Original Message ----- 
From: "marziasedino" <marziasedino@xxxxxxxx>
To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
Sent: Thursday, January 17, 2008 4:33 AM
Subject: [EnergyPlus_Support] Re: Greenhouse airflow simulation#2



Dear Lixing,
Thank you for your prompt response.
The openings that to us didn't seem to work are the four detailed
openings on the partition wall between the 6339 and 6346 zones. Their
names:
H_6339_5_0_0_0_1
H_6339_5_0_0_0_2
H_6339_5_0_0_0_3
H_6339_5_0_0_0_4
And their correspondent on the other zone (which you told us to
delete)
H_6346_10003_0_10007_10009
H_6346_10003_0_10007_10010
H_6346_10003_0_10007_10011
H_6346_10003_0_10007_10012.
The problem is that whether they are open or closed, the airflows
through them showed in the output report didn't change much. In the
meanwhile we realized it might be because of the "air mass flow
coefficient when the opening is closed" value specified in
the "airflow network multizone component detailed opening". We
lowered it, very close to 0 as we assumed when those openings are
closed there shouldn't be any infiltrations, and the model seems
working better. We hope it is right.
Also
You told us not to define airflow network surfaces twice but to use
the schedule. The fact is that in our case we think can't just use
schedule, as the ventilation control mode "temperature" only allows
you to specify the temperature (Tset) above which the surface is
opened, and not an upper and lower limit. How can we proceed in this
last case?
Actually we tried to control the surfaces opening schedule by
checking the zones temperatures on both side of the partition, that
is why we needed to define them twice. Do you think this is affecting
our results?

Thanks a lot

Marzia




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