Re: [EnergyPlus_Support] Re: Window AC or Unitary - Coil:DX:CoolingBypassFactorEmpirical

["Michael J. Witte" <mjwitte@xxxxxxxx>]

Answering questions from this and three prior messages.

1.  Version 1.4 and version 2.0 can both be installed on the same computer with 
no problem as long as they are installed in different folders, such as 
EnergyPlusV1-4-0 and EnergyPlusV2-0-0.

2.  The RDD output file is created by putting the following command in the idf 
file and running the simulation:  REPORT, Variable Dictionary;

3.  Colored cells in IDF Editor indicate a value which is outside the range of 
the max and min values for that particular field.  This has nothing to do with 
output results.

4.  When ZONE SIZING or SYSTEM SIZING objects are present in the input file, 
design day environments will always be run as part of the sizing calculations.  
This is true even if some or all of the autosized values are overriden using 
"Flow/zone" or other options.

5.  Regarding airflow rate errors.  Coil:DXCoolingBypassFactorEmpirical and AIR 
CONDITIONER:WINDOW:CYCLING are intended for modeling single-speed constant-
volume cooling units.  Per the Input Output Reference, there is a limited range 
of valid flow rate to cooling capacity ratios.  There is no current model for 
DX system with multiple fan  speeds.  The alternative is to use a DX VAV system 
with COIL:DX:MultiSpeed:CoolingEmpirical, but this requires continous fan 
operation.  See example file 5ZoneAutoDXVAV.idf.

Mike


On 22 Apr 2007 at 23:54, ooikoonbeng2004 wrote:

> Hi Linda, 
> 
> A 7.04KW CU-C24CTH National Panasonic air conditioner is used on the 
> BS1 zone. i was informed, that the rated air volume is 0.253m3/s. My 
> rough measurements with an AirFlow anemometer, was 0.197379, 
> 0.221949 and 0.235053 for low, med and high fan speeds.
> 
> When 0.253 was entered into the Coil:DXCoolingBypassFactorEmpirical, 
> many understandable out of range errors appeared. But even if i 
> changed to a higher figure to be within the range allowed by E+, 
> still a few thousand out of range errors appeared. i shall try again 
> in a month's time.
> 
> ooi
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Linda Lawrie <linda@...> 
> wrote:
> >
> > Rated Total Cooling Capacity would be the "required" total cooling 
> > capacity in an autosized run.  You might need to find a 
> manufacturer 
> > that has that "rated cooling capacity" for the unit.
> > 
> > Autosized component results are put on the .eio file.
> > 
> > 
> > Linda
> > 
> > EnergyPlus WebSite: http://www.energyplus.gov
> > Owner: EnergyPlus_Support list
> > Member: EnergyPlus Development Team
> > 
> > 
> > 
> > [Non-text portions of this message have been removed]
> >
> 
> 
> 
> 
> 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.pdf under the
> Documentation link 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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