[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [EnergyPlus_Support] Re: Cooling set-point not fully achieved

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Re: Cooling set-point not fully achieved
From: Richard Raustad <RRaustad@xxxxxxxxxxxx>
Date: Thu, 07 Feb 2008 12:42:02 -0500
Comment: DomainKeys? See http://antispam.yahoo.com/domainkeys
Delivered-to: linda@xxxxxxxxxx
Delivered-to: mailing list EnergyPlus_Support@xxxxxxxxxxxxxxx
Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=lima; d=yahoogroups.com; b=hLpeTmgyhbfh0qsNDopiYr11WX6RxSr3uXsDYHkcBO7b13+JnUxVuTwvZwErEju8DBrPiiGyTL3ozIFLztcThJXOScAGWPBqPQnC5l4btUmBDS/p5wsAoKX5l+aiXLac;
In-reply-to: <foffjj+m7fa@eGroups.com>
List-id: <EnergyPlus_Support.yahoogroups.com>
List-unsubscribe: <mailto:EnergyPlus_Support-unsubscribe@yahoogroups.com>
Mailing-list: list EnergyPlus_Support@xxxxxxxxxxxxxxx; contact EnergyPlus_Support-owner@xxxxxxxxxxxxxxx
Organization: Florida Solar Energy Center
References: <foffjj+m7fa@eGroups.com>
Reply-to: EnergyPlus_Support@xxxxxxxxxxxxxxx
Sender: EnergyPlus_Support@xxxxxxxxxxxxxxx
User-agent: Thunderbird 2.0.0.9 (Windows/20071031)

If it truly is a predicted load issue, I would think purchased air would 
show similar results. It can't hurt to try.

anarui.oliveira wrote:
>
> Is this problem equally likely to happen if I use a Purchased Air
> approach?
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> <RRaustad@...> wrote:
> >
> > You could try increasing the time step in hour. I have no other
> > suggestions. This is a known issue and we are working to correct it.
> >
> > anarui.oliveira wrote:
> > >
> > > That field is already set to 1, and time step in hours is set to
> 4.
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > > <RRaustad@> wrote:
> > > >
> > > > What you describe is not a capacity issue, it is related to the
> > > > prediction of loads. If you add the report variable
> for "Zone/Sys
> > > > Sensible Load Predicted" and set the report variable frequency
> to
> > > > detailed, you will see why this is happening. Try reducing the
> > > Minimum
> > > > System Time Step in the System Convergence Limits object. You
> > > probably
> > > > will not eliminate the problem, but it should get better.
> > > >
> > > >
> > > > anarui.oliveira wrote:
> > > > >
> > > > > What if, in a similar (heating) case, water flow doesn't
> reach the
> > > > > maximum when the problem occurs, and increasing the air flow
> > > causes
> > > > > further departure from temperature setpoint?...(Less than
> about
> > > 1.5
> > > > > times the auto-sized air flow also leads to poorer setpoint
> > > > > tracking); reported air flow is always equal to the constant
> > > volume
> > > > > fan flow, and ouside air flow rate is (and must be) user
> > > specified.
> > > > >
> > > > > Regards,
> > > > > Ana.
> > > > >
> > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > > > > <RRaustad@> wrote:
> > > > > >
> > > > > > Then try again to manually size the coil in the problem
> zone to
> > > > > twice
> > > > > > the size reported in the eio file. Also increase the air
> flow
> > > rate
> > > > > for
> > > > > > that fan coil unit and fan to twice the autosized value. If
> > > htis is
> > > > > > happening in more than 1 zone, then just pick 1 for now to
> test
> > > > > this out.
> > > > > >
> > > > > > Then tell me what happens to the maximum zone temperature.
> Did
> > > the
> > > > > > maximum zone temperature go down? Also tell me if the water
> flow
> > > > > rate is
> > > > > > at a maximum when the zone temperature exceeds the set
> point.
> > > You
> > > > > can
> > > > > > report "System Node VolFlowRate" for the coil water inlet
> node
> > > and
> > > > > fan
> > > > > > coil air inlet node to easily match volumetric flow rate
> with
> > > your
> > > > > inputs.
> > > > > >
> > > > > > This just sounds like a sizing issue and should be easily
> > > resolved.
> > > > > >
> > > > > > anarui.oliveira wrote:
> > > > > > >
> > > > > > > Apparently, yes, but I set it to autosize (and I think I
> > > already
> > > > > did
> > > > > > > a trial with a larger, user-defined, water flow rate)...
> > > > > > >
> > > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard
> Raustad
> > > > > > > <RRaustad@> wrote:
> > > > > > > >
> > > > > > > > I have not looked at your input file, can you tell me
> if the
> > > > > water
> > > > > > > mass
> > > > > > > > flow rate through the fan coil is at a maximum when the
> > > cooling
> > > > > set
> > > > > > > > point is not met?
> > > > > > > >
> > > > > > > > anarui.oliveira wrote:
> > > > > > > > >
> > > > > > > > > Please forgive me for insisting, but I DO have some
> > > urgency on
> > > > > > > this
> > > > > > > > > one...
> > > > > > > > > Again, thanks for any help,
> > > > > > > > > Ana.
> > > > > > > > >
> > > > > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > > > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > > > > > > <mailto:EnergyPlus_Support%
> > > > > 40yahoogroups.com>, "anarui.oliveira"
> > > > > > > > > <anarui.oliveira@> wrote:
> > > > > > > > > >
> > > > > > > > > > Hi again.
> > > > > > > > > >
> > > > > > > > > > I'm uploading a new file (Zone36598_cFancoil_exp),
> > > hoping
> > > > > that
> > > > > > > > > someone
> > > > > > > > > > can help me figure out why the cooling setpoints
> are not
> > > > > being
> > > > > > > > > achieved
> > > > > > > > > > for all times when the controls are active (namely
> in
> > > Zone
> > > > > > > 36598).
> > > > > > > > > The
> > > > > > > > > > model consists of Fancoil units created with Compact
> > > HVAC,
> > > > > and
> > > > > > > then
> > > > > > > > > > edited in the expanded file.
> > > > > > > > > > I tried several user-defined and sizing options, but
> > > > > couldn't
> > > > > > > solve
> > > > > > > > > the
> > > > > > > > > > temperature peaks above 25ºC.
> > > > > > > > > >
> > > > > > > > > > Thanks in advance,
> > > > > > > > > > Ana Rui.
> > > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > > > --
> > > > > > > > Richard A. Raustad
> > > > > > > > Senior Research Engineer
> > > > > > > > Florida Solar Energy Center
> > > > > > > > University of Central Florida
> > > > > > > > 1679 Clearlake Road
> > > > > > > > Cocoa, FL 32922-5703
> > > > > > > > Phone: (321) 638-1454
> > > > > > > > Fax: (321) 638-1439 or 1010
> > > > > > > > Visit our web site at: http://www.fsec.ucf.edu 
> <http://www.fsec.ucf.edu>
> > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>
> > > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>>
> > > > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>
> > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>>>
> > > > > > > >
> > > > > > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > > > --
> > > > > > Richard A. Raustad
> > > > > > Senior Research Engineer
> > > > > > Florida Solar Energy Center
> > > > > > University of Central Florida
> > > > > > 1679 Clearlake Road
> > > > > > Cocoa, FL 32922-5703
> > > > > > Phone: (321) 638-1454
> > > > > > Fax: (321) 638-1439 or 1010
> > > > > > Visit our web site at: http://www.fsec.ucf.edu 
> <http://www.fsec.ucf.edu>
> > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>
> > > <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu> 
> <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>>
> > > > > >
> > > > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > > > >
> > > > >
> > > > >
> > > >
> > > > --
> > > > Richard A. Raustad
> > > > Senior Research Engineer
> > > > Florida Solar Energy Center
> > > > University of Central Florida
> > > > 1679 Clearlake Road
> > > > Cocoa, FL 32922-5703
> > > > Phone: (321) 638-1454
> > > > Fax: (321) 638-1439 or 1010
> > > > Visit our web site at: http://www.fsec.ucf.edu 
> <http://www.fsec.ucf.edu>
> <http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>>
> > > >
> > > > UCF - From Promise to Prominence: Celebrating 40 Years
> > > >
> > >
> > >
> >
> > --
> > Richard A. Raustad
> > Senior Research Engineer
> > Florida Solar Energy Center
> > University of Central Florida
> > 1679 Clearlake Road
> > Cocoa, FL 32922-5703
> > Phone: (321) 638-1454
> > Fax: (321) 638-1439 or 1010
> > Visit our web site at: http://www.fsec.ucf.edu <http://www.fsec.ucf.edu>
> >
> > UCF - From Promise to Prominence: Celebrating 40 Years
> >
>
>  

-- 
Richard A. Raustad
Senior Research Engineer
Florida Solar Energy Center
University of Central Florida
1679 Clearlake Road
Cocoa, FL  32922-5703
Phone:   (321) 638-1454
Fax:     (321) 638-1439 or 1010
Visit our web site at: http://www.fsec.ucf.edu

UCF - From Promise to Prominence: Celebrating 40 Years



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

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/

References:
- [EnergyPlus_Support] Re: Cooling set-point not fully achieved
  - From: anarui.oliveira

Prev by Date: [EnergyPlus_Support] Re: Cooling set-point not fully achieved
Next by Date: [EnergyPlus_Support] Fwd: Re: Cooling set-point not fully achieved
Previous by thread: [EnergyPlus_Support] Re: Cooling set-point not fully achieved
Next by thread: [EnergyPlus_Support] Report Variables in DELight-Detailed Comparison.idf
Index(es):
- Date
- Thread