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

To: EnergyPlus_Support@xxxxxxxxxxxxxxx
Subject: Re: [EnergyPlus_Support] Fwd: Re: Cooling set-point not fully achieved
From: Richard Raustad <RRaustad@xxxxxxxxxxxx>
Date: Thu, 07 Feb 2008 16:05:32 -0500
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Ana, which weather file are you using?

Richard Raustad wrote:
>
> Well, I would rather see a graph, but from what you describe, yes it does.
>
> If you wish, email a graph in the spreadsheet (save it as xls) to:
> rraustad@xxxxxxxxxxxx <mailto:rraustad%40fsec.ucf.edu>
>
> anarui.oliveira wrote:
> >
> > Differences go up to 1ºC. Does it fit the behaviour of the problem
> > you describe?
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, Richard Raustad
> > <RRaustad@...> wrote:
> > >
> > > I have looked at this control issue before. I don't think it's the
> > > mixing objects or other zone loads. And your offset from the set
> > point
> > > should be pretty small. Not to worry, the overall annual energy use
> > > should be pretty close. Beside, if you run this building using a
> > > different building simulation tool, your likely to get a different
> > > answer. And I believe the difference in these answers will be
> > greater
> > > than the difference in annual energy use due to the set point
> > offset. If
> > > it happens all the time, adjust your set point so the "average"
> > zone
> > > temperature is near your target temperature.
> > >
> > > anarui.oliveira wrote:
> > > >
> > > > Could the mixing objects or anything like that contribute to this
> > > > problem? Or some definitions such as humidity ratios or the
> > like?...
> > > > Getting worried here... the aim was exactly to predict the energy
> > > > consumption of a building throughout a year (for official, legal
> > > > purposes)...
> > > >
> > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx 
> <mailto:EnergyPlus_Support%40yahoogroups.com>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > <mailto:EnergyPlus_Support%40yahoogroups.com>, "anarui.oliveira"
> > > > <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>
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > > <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>
> > > > <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>
> > > > > > <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>
> > > > > > > > <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>
> > > > > > > > > > <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>>>>
> > > > > > > > <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>>>>>
> > > > > > > > <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>>>>
> > > > > > <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>>>
> > > > > > <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>>>
> > > > <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>>>
> > > > <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
> > > > >
> > > >
> > > > --- End forwarded message ---
> > > >
> > > >
> > >
> > > --
> > > 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



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

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