[EnergyPlus_Support] Re: Sizing warning message on temperature difference

["patrick_bivona" <patrick.bivona@xxxxxxxxx>]

Jean,

Yes, this is happening during the sizing run. I've run the simulation for the design days as you suggested. The zone temperature stays around the cooling setpoint (24 degC) during HVAC operation hours and never reaches 20 degC outside HVAC operation hours.

Also, I'm getting similar messages for other zones that have the same 16 degC design supply air temperature. In all cases, the messages are reported with a zone temp of exactly 20.00 degC. I'm still unclear where this temperature comes from.

Patrick

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jean marais" <jeannieboef@...> wrote:
>
> This is happening during your sizing day. So I think the max temp of your zone is only reaching 20 deg C during this day. Run the simulation for the sizing period to see.
> 
>   SimulationControl,
>     Yes,                     !- Do Zone Sizing Calculation
>     Yes,                     !- Do System Sizing Calculation
>     Yes,                     !- Do Plant Sizing Calculation
>     Yes,                      !- Run Simulation for Sizing Periods
>     No;                     !- Run Simulation for Weather File Run Periods
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "patrick_bivona" <patrick.bivona@> wrote:
> >
> > Hi Jean,
> > 
> > I am indeed using a VAV (through the HVACTemplate objects) but I've disabled reheat (Reheat Coil Type = None). The zone heating setpoint is 5degC anyway.
> > 
> > Patrick
> > 
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "jeannieboef@" <jeannieboef@> wrote:
> > >
> > > You are using a vav with reheat, right. In clg mode it will reheat to  
> > > the zone htg setpoint not the zone clg setpoint.
> > > 
> > > Sent from my iPhone (excuse the brevity)
> > > Mit freundlichen Grü�en
> > > 
> > > i. A.
> > > Jean Marais
> > > B.Eng (Mech)
> > > LEED Accredited Professional
> > > Building Energy Modeling with DesignBuilder and EnergyPlus
> > > 
> > > b.i.g. bechtold
> > > INGENIEURGESELLSCHAFT MBH
> > > KeithstraÃ?e 6
> > > 10787 Berlin
> > > Tel.   +49 30 6706662-23
> > > Fax  +49 30 6706662-18
> > > Marais.Jean@
> > > www.designbuilder-big.com
> > > www.big-gruppe.com/tga
> > > Firmensitz: Berlin, Registergericht: Amtsgericht Charlottenburg, HRB  
> > > 112242 B
> > > Geschäftsführer: Bernd Bechtold, Tino Laupitz, Carsten Teichmann
> > > 
> > > "The LEED® (Leadership in Energy and Environmental Design) Green  
> > > Building
> > > Rating System is the nationally accepted benchmark for the design,  
> > > construction,
> > > and operation of high performance green buildings."
> > > Other LEED descriptive copy may be found on the USGBC Web site: http://www.usgbc.org/leed
> > > 
> > > Official Reseller for DesignBuilder in Germany and Austria
> > > 
> > > 
> > > 
> > > On 12.06.2013, at 03:37, Patrick Bivona <patrick.bivona@>  
> > > wrote:
> > > 
> > > > Hi,
> > > >
> > > > I'm getting this warning message after a run:
> > > >
> > > >    ** Warning ** SizeZoneEquipment: Supply air temperature  
> > > > (calculated) within 5C of zone setpoint temperature
> > > >    **   ~~~   ** ...check zone thermostat set point and design  
> > > > supply air temperatures
> > > >    **   ~~~   ** ...zone = "ZONE 1F ENTRANCE WEST" first occurrence  
> > > > during cooling load calculations
> > > >    **   ~~~   ** ...predicted zone cooling load = -863.19 W
> > > >    **   ~~~   ** ...zone temperature            = 20.00 C
> > > >    **   ~~~   ** ...supply air temperature      = 16.00 C
> > > >    **   ~~~   ** ...temperature difference      = -4.00000 C
> > > >    **   ~~~   ** ...calculated mass flow rate   = 0.21163 kg/s
> > > >
> > > > I understand the general purpose of the temperature difference  
> > > > check: avoid high flow rates.
> > > > What I don't understand is why the "zone temperature" is reported as  
> > > > being 20 degC, when my thermostat cooling setpoint is 24 degC.
> > > >
> > > > Am I wrong in assuming that "zone temp" should be the cooling  
> > > > setpoint? If so, why recommend to check the zone thermostat in the  
> > > > warning message?
> > > >
> > > > I'm confused!
> > > >
> > > > Thanks in advanced for your help,
> > > > Patrick Bivona
> > > >
> > > >
> > >
> >
>




------------------------------------

Primary EnergyPlus support is found at:
http://energyplus.helpserve.com or send a message to energyplus-support@xxxxxxxx

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 currently allowed but be mindful that not everyone has a high speed connection.  Limit attachments to small files.

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:
    EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    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/