[EnergyPlus_Support] Re: outside air problem

["hbn_pch" <hbn_pch@xxxxxxxxxxxx>]

Mike,if i want to supply conditioned outside air,for example,i want 
to supply outside air in 14C for dehumidification in summer and 
supply outside air in 18C in winter,then i have to separate the 
outside air system from the fan coil system.The outside air unit 
contained a OA mixer,a cooling coil,a heating coil and a supply fan.
(it seemed to the supply side of the primary air loop).But how can i 
connect it to the fan coil unit?The fan coil unit is a zone equipment 
but not a terminal unit.Is it possible?

  pch

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
<mjwitte@g...> wrote:
>
> 1.  Both methods will introduce the same quantity of outdoor air 
into the 
> system.  Not all fan coil system rely on a separate system to 
introduce outdoor 
> air, some are built with an outside air intake.  Is there a big 
difference 
> between simulating it as a separate system or as part of the fan 
coil unit?  
> That depends on whether the separate system would do any special 
control for 
> humidity.  If not, the difference in results will be small.  So use 
the 
> simplest method unless there is a significant reason to use a more 
complex 
> model.
> 
> 2.  These values have a very small impact on coil sizing.  The 
default values 
> can be used for most applications.
> 
> 2b.  Consideration of humidity control is very regional.  You 
should model what 
> is important for your climate.
> 
> Mike
> 
> 
> On 14 Nov 2005, at 9:39, eric_zhou1223 wrote:
> 
> > Hi,
> > 
> > 1.For the Dxcoil and Fancoil system, users may define required 
fresh 
> > air for a zone using the outdoor air mixer. The autosized value 
in 
> > the field ¡°maximum outside air flow rate¡± could satisfy the 
> > ventilation requirement of occupants. My question is , as we 
know, 
> > since there exists in reality another air loop specially for the 
> > fresh air inducement, is this method here only a simulative 
method 
> > to handle the ventilation problem? Can I use this simplified way 
here
> > (defining the desired fresh air amount in above field ) to 
simulate 
> > a ¡° Fancoil + outdoor air¡± system, instead of using a complex  
> > Fancoil system along with an additional Fresh Air Handling Unit 
to 
> > meet the ventilation demand?  What is the difference between the 
two 
> > method from a fresh air supply perspective?
> > 
> > 2  How can I identify the fields ¡°Zone cooling/heating design 
> > supply air humidity ratio¡±?  The default values can be regarded 
as  
> > ¡°standard ¡± values or need to be revised based on each 
situation ? 
> > I thought the value , specially for the heating , seem to be over 
> > dry.
> > 
> > Is ignoring the humidity control a common practice for an office 
> > building energy simulation? 
> > 
> > Thank you very much
> > 
> > Eric
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 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@g...
>






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