[EnergyPlus_Support] Re: humidity control

["hbn_pch" <hbn_pch@xxxxxxxxxxxx>]

Thanks very much!I will check again.

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
<mjwitte@...> wrote:
>
> 1.  The zone supply air flow rates are calculated by ZONE SIZING 
based on 
> sensible load requirements, so the SYSTEM SIZING object will not 
alter the air 
> flow rates.  Also, note that the "type of load to size on" field in 
the SYSTEM 
> SIZING object only accepts "sensible" (see Input Output 
Reference).  I see that 
> the IDD file does not mention this, so I will add a note.
> 
> 2. In the file you submitted last week, in CONTROLLER:OUTSIDE AIR, 
ECONOMIZER 
> is active.  If that is active in your current idf, then that would 
explain the 
> increase in outside air flow.
> 
> 3. Check the setpoint controls on the main heating coil.  It should 
attempt to 
> heat the air to the desired setpoint, assuming that the entering 
hot water 
> temperature is adequate.
> 
> Mike
> 
> 
> On 6 Jun 2006 at 9:26, hbn_pch wrote:
> 
> > Mike,i report the system node temp and system node 
volflowrate,find 
> > that system node temp is low enough(perhaps had achieved dew 
point) 
> > but system node volflowrate remain max(sizing in eio).It seems 
that 
> > the air loop capability is sized too small.Then i adjust the 
sizing 
> > parameter to 2 and find it can control temp and hum well.I try 
> > another model for a test,find it should set sizing parameter to 3 
for 
> > control aim.All is autosized in the model.Why is it sized so 
small?
> > Does it just sized the sensible load?But when i change the size 
type 
> > in system sizing to total,the result did not change yet.
> > 
> > question 2 :I set 0.0094m3/s in the zone sizing for outside air 
and 
> > oa method is flow/person.There is 20 people in the zone,min oa 
remain 
> > 1.So for all day,the outside air volflowrate should remain 
> > 0.188m3/s.But for simulation ,i find sometimes the outside air 
> > volflowrate would increase.What caused this change?
> > 
> > question 3 :When i use vav:reheat,i set the vav outlet node temp 
in 
> > winter to 16.I find in winter design day,the vav damper remain 
min 
> > and the vav outlet node temp did not achieve setpoint temp.I 
checked 
> > other simulation day,find that the vav outlet node temp did't not 
> > achieved setpoint at all,sometimes are very small.Then it will be 
> > reheated by reheat coil .How did the main heating coil and reheat 
> > coil distribue the heating task?
> > 
> >   Appreciated your kind help.
> >   PCH
> > 
> > 
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "mjwitte" <mjwitte@> 
> > wrote:
> > >
> > > If you report the System Node Setpoint Temp at the air loop 
outlet
> > > node, you will see that the controller is trying to control to 
the
> > > specified RH setpoint, but the cooling coil is unable to supply 
air
> > > that is cold enough to meet this.  I tried making some changes 
to 
> > get
> > > this to autosize to a better result, but have not been 
successful 
> > yet.
> > > 
> > > Mike
> > > 
> > > 
> > > 
> > > 
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "hbn_pch" <hbn_pch@> 
> > wrote:
> > > >
> > > > Dear,
> > > >    I want to control humidity for a single zone.I create the 
> > model like 
> > > > the examplefile '5ZoneWaterCooled_HighRHControl.idf',but the 
Zone 
> > Air 
> > > > Relative Humidit was not controlled to setpoint in my 
model,while 
> > the 
> > > > examplefile can.
> > > >    I really can't find the problems.appreciated your kind 
> > help.I've 
> > > > upload  correlative file named 'RH CONTROL.zip'
> > > >    Thanks very much
> > > >    pch
> > > >
> > >
> > 
> > 
> > 
> > 
> > 
> > 
> > 
> > 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@...
>







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