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Re: [EnergyPlus_Support] air flow limit



The DX coil model warns when the airflow rate to capacity ratio is outside the 
typical range, because this may impact the results.  If the airlfow is only a 
little out of range, the results are probably acceptable.  What type of 
equipment is this?  The reported airflow rate is higher than the upper limit on 
the warning check, so this system will not dehumidify very well.  For the DX 
coil capacity, check to see if the catalog data is the gross coil capacity or 
the net capacity (including the heating effect of the fan).  The DX coil input 
should be the gross capacity, which for cooling is the larger of the two values.

Mike


On 3 Oct 2005, at 1:25, dust_broom wrote:

> Dear all:
> 
> During the simulation this error came up, but I dont understand the 
> purpose!
> 
> ** Severe  ** Sizing: COIL:DX:COOLINGBYPASSFACTOREMPIRICAL "COIL 
> SISTEMA UNDERFLOW": Rated air volume flow rate per watt of rated 
> total cooling capacity is out of range. See Input-Output Reference 
> Manual for valid range.
>    ** Warning ** COIL:DX:COOLINGBYPASSFACTOREMPIRICAL "COIL SISTEMA 
> UNDERFLOW" - Air volume flow rate per watt of rated total cooling 
> capacity is out of range at   7.120244238500870E-005 m3/s/w.
>    **   ~~~   **  ...VolumeFlowperRatedTotCap=7.120E-005 Occurrence 
> info=SUMMER DESIGN DAY IN TITLE, 07/21 01:00 - 02:00
>    **   ~~~   ** Expected range for VolumeFlowperRatedTotalCapacity=
> [  3.356000000000000E-005--  6.713000000000000E-005]
>    **   ~~~   ** Possible causes include inconsistent air flow rates 
> in system components,
>    **   ~~~   ** inconsistent supply air fan operation modes in coil 
> and furnace/unitary objects,
>    **   ~~~   ** or variable air volume [VAV] system using incorrect 
> coil type.
> 
> 
> 
> 
>  The air flow used in this simulation was took from the catalog, so 
> I should not change it. I would like to know if there is any way to 
> avoid this error without changing the flow rate, or if I keep the 
> air flow rate, will this result in substancial errors? 
> 
> Thank you, Emanuel
> 
> 
> 
> 
> 
> 
> 
> 
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
> 
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
> 
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
> 
> EnergyPlus Documentation is searchable.  Open EPlusMainMenu.idf and press the
> "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 



========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx




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