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[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

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Marzia:
> 
> I looked at the uploaded input file. Since I don't know which 
weather file 
> you are using, I used Chicago weather data to perform the test. In 
addition, 
> I added one more report variable of Window/Door Venting Opening 
Factor to 
> see large opening response. Output results show these large 
opneings 
> response as specified. Please let me know which opening does not 
response as 
> you specified.
> 
> One more suggestion is that please don't specify any interior 
surfaces twice 
> in the AirflowNetwork model. You can specify winter and summer 
control 
> conditions using schedules.
> 
> Best regards,
> 
> Lixing Gu
> 
> 
> ----- Original Message ----- 
> From: "marziasedino" <marziasedino@...>
> To: <EnergyPlus_Support@xxxxxxxxxxxxxxx>
> Sent: Wednesday, January 16, 2008 3:55 AM
> Subject: [EnergyPlus_Support] Greenhouse airflow simulation
> 
> 
> Hello,
> I am trying to simulate a greenhouse space adjacent to a two thermal
> zones building, I created the model with DesignBuilder and exported
> it in E+,
> The greenhouse external wall has got a big window open during summer
> and closed during winter time.
> The partition wall between the greenhouse and the adjacent thermal
> zone has got 4 detailed openings (and one main door) which should
> open as specified in the following schedule being their ventilation
> control mode "temperature":
> - during summer when the temperature of the adjacent thermal
> zone (zone name: 6346) is higher than 22°C and higher that the
> outside temperature;
> - during winter when the temperature of the greenhouse (zone
> name: 6339) is higher than 22°C and higher than the outside
> temperature.
> I defined those openings twice in
> the "AirflowNetwork:Multizone:Surface": the first time considering
> them belonging to the greenhouse zone (6339) and the second time
> considering them belonging to the thermal zone (6346) in order to
> assign them the two specified different schedules (summer and 
winter)
> as they refer to different zones temperatures.
> Nevertheless when I analyse AirflowNetwork Volume Flow Rate outputs 
I
> can't see the openings work correctly: I expect to see more flow 
when
> they should be open and only infiltrations when they are closed; but
> this is not happening.
> 
> Could you tell me please if there is a better way to model them?
> I uploaded my file in the appropriate space, its name
> is: "greenhouse#1"
> 
> Thanks
> 
> Marzia Sedino
> 
> 
> 
> 
> The primary EnergyPlus web site is found at:
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> 
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under the 
> Documentation link and press the "search" button.
> 
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>




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