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Re: [EnergyPlus_Support] Re: Main Branch Cooling Coil and Heating Coil Control Nodes



The purpose of SET POINT MANAGER:MIXED AIR is to subtract fan heat from a 
reference setpoint.  For the economizer operation, it is required.  For cooling 
coils in a draw-thru configuration it is not required, but it can help reduce 
iterations by giving the cooling coil controller some advance knowledge of the 
fan impact.

Mike


On 28 Feb 2006 at 9:20, Elmer Morrissey wrote:

> Hi Mike,
> 
> Thank yoiu for your prompt answer. Just so I know for future systems,
> do you have to use the SET POINT MANAGER:MIXED AIR even though the
> system is set up to take 100% fresh air?
> 
> Kind regards
> 
> -Elmer 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte"
> <mjwitte@...> wrote:
> >
> > EnergyPlus controllers all have a finite control tolerance
> (specified in the 
> > controller object), so the control is not perfect.  My guess is that
> the 
> > heating and cooling coil controllers are battling each other.  
> > 
> > If I understand your application correctly, SET POINT MANAGER:SINGLE
> ZONE 
> > HEATING and SET POINT MANAGER:SINGLE ZONE COOLING can be used to
> control your 
> > system.  
> > 
> > Move the heating coil to be after the fan and place the SET POINT 
> > MANAGER:SINGLE ZONE HEATING setpoint on the heating coil outlet node.  
> > 
> > Place the SET POINT MANAGER:SINGLE ZONE COOLING setpoint on the fan
> outlet node 
> > and use a SET POINT MANAGER:MIXED AIR to place a setopint minus fan
> heat 
> > correction on the cooling coil outlet node.
> > 
> > Mike
> > 
> > 
> > On 27 Feb 2006 at 15:55, Elmer Morrissey wrote:
> > 
> > > Hello all,
> > > 
> > > I am getting max iterations on a loop  and I'm trying to go through 
> > > the file iteratively to locate the source of the problem (node 
> > > connections, correct flowrates etc). 
> > > 
> > > A brief description of the system I am trying to emulate:
> > > 
> > > I have a fixed flow system. The AHU takes full fresh air before 
> > > entering a cooling coil, a heating coil and a supply fan (no 
> > > reheat). The temperature leaving the supply fan is varied according 
> > > to zone temperature.
> > > 
> > > What I have done:
> > > 
> > > I have two Controller:simple objects which both use the same control 
> > > node (the supply fan outlet node). I have set this at 18oC. However, 
> > > I would prefer to let EnergyPlus decide what the setpoint should be.
> > > 
> > > Could this be the source of my problems?
> > > 
> > > Kind regards
> > > 
> > > -Elmer
> > > 
> > > 
> > > 
> > > 
> > > 
> > > 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@...
> >
> 
> 
> 
> 
> 
> 
> 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
> 
> 
> 
>  
> 
> 
> 
> 






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