RE: [EnergyPlus_Support] Re: ZoneVentilation Volume Standard Density vary

[Lixing Gu <gu@xxxxxxxxxxxx>]

Robin:

This is caused by air density calculations using different pressures,
temperature, and humidity ratio.

In the calculation subroutine, the mass flow rate is required in the
calculations and is equal to the volumetric flow rate from your input times
air density as a function of outdoor conditions (T, P, and W). In the report
subroutine, the volumetric flow is calculated using the mass flow rate
divided by the air density as a function of standard condition. The
different densities are used in calculation and reporting. That is why you
see minor differences shown in outputs.

Hope this helps.

Lixing

-----Original Message-----
From: EnergyPlus_Support@xxxxxxxxxxxxxxx
[mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of rgen1202
Sent: Wednesday, May 04, 2011 3:17 PM
To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: [EnergyPlus_Support] Re: ZoneVentilation Volume Standard Density
vary

Lixing,

Thanks for your answer. I uploaded the file in Files>Problem_Submittals 
http://tech.groups.yahoo.com/group/EnergyPlus_Support/files/_Problem_Submitt
als/. 
Its called ventilation_mech.idf . Its a single zone building with only
ZoneVentilationDesign Flow Rate. I used the FRA_LYON_IWEC.epw for the
weather (I uploaded it too). 

Thanks in advance.

Regards.

Robin

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Lixing Gu <gu@...> wrote:
>
> Robin:
> 
> If you report Zone Ventilation Volume Standard Density, it should give you
a
> constant value. Please upload the input file and tell us the weather file
> name if this weather file is downloaded from the energyplus web site. We
> will take a look.
> 
> Lixing
> 
> -----Original Message-----
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of Lixing Gu
> Sent: Wednesday, May 04, 2011 1:29 PM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: RE: [EnergyPlus_Support] ZoneVentilation Volume Standard Density
> vary
> 
> Robin:
> 
> I think you may use one of two output variables to report volume flow
rates:
> 
> HVAC,Sum,Zone Ventilation Volume Flow Rate Current Density [m3/s]
> HVAC,Sum,Zone Ventilation Volume Flow Rate Standard Density [m3/s]
> 
> It was found as a bug to report volume flow rates and was fixed for the
next
> release. It is a report error and has no impact of simulation results.
> 
> Lixing  
> 
> -----Original Message-----
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of rgen1202
> Sent: Wednesday, May 04, 2011 11:56 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] ZoneVentilation Volume Standard Density vary
> 
> Hello,
> 
> I have a question about the ZoneVentilation DesignFlowRate.When I set the
> Design Flow Rate to a constant value (assuming 0.086162 m3/s, for a single
> zone), I don't understand why the output variable Zone Ventilation Volume
> Standard Density (hourly) is varying. Can someone explain it? I have
checked
> the settings and I have all minimum and maximum temperature setted to
> default value (this mean no shutoff of ventilation) , the maximum wind
speed
> is 40 m/s (no shutoff) and only the constant term coeeficient is set to 1,
> the other are to 0. Of course, I have tested this setting for a single
zone,
> without any infiltration or other air system.
> 
> Thanks in advance.
> 
> Robin GENOUD
> 
> 
> 
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> ------------------------------------
> 
> Primary EnergyPlus support is found at:
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> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
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> Attachments are currently allowed but be mindful that not everyone has a
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Attachments are currently allowed but be mindful that not everyone has a
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EnergyPlus Documentation is searchable.  Open EPlusMainMenu.pdf under the
Documentation link and press the "search" button.
Yahoo! Groups Links







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Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

The primary EnergyPlus web site is found at:
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The group web site is:
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Attachments are currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

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