[EnergyPlus_Support] Re: Heating/Setpoint Controller

["ecoeficientees" <ecoeficiente@xxxxxxxxx>]

Dear James,
I am afraid that Energyplus does not control heating and cooling coil operation for a dual setpoint, at least when they are water coils (not sure about DX Coils). Even VAV HVAC Template says so in the help file (that you need to use availability managers to control when the coils are operating).

It is frustating, as I have said in another reply, because it seems that EMS is the only solution to the problem.

Regards,

Germán.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Jim Dirkes" <jim@...> wrote:
>
> Dear Germán,
> 
> EnergyPlus will automatically control the operation heating and cooling coil
> according to your SetpointManagers.  It will not operate cooling and heating
> simultaneously unless you have some sort of CoolReheat control.  (You can
> see this is you create output variables for the temperature node downstream
> of each coil)
> 
> Regarding the frost warnings, you can:
> 
> ·         Ignore the warnings  (probably this does not affect accuracy too
> much, but you will get a lot of warnings!)
> 
> ·         Create a two-speed DX coil  (This will probably reduce the number
> of warnings)
> 
> ·         Employ EMS to prevent DX coil operation below a certain outdoor
> temperature (e.g. 10-12C)
> 
>  
> 
> The Building Performance Team
> James V. Dirkes II, P.E., BEMP , LEED AP
> 1631 Acacia Drive NW
> Grand Rapids, MI 49504
> 616 450 8653
> 
>  
> 
> From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx] On Behalf Of ecoeficientees
> Sent: Friday, April 13, 2012 9:30 AM
> To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> Subject: [EnergyPlus_Support] Re: Heating/Setpoint Controller
> 
>  
> 
>   
> 
> Hi, I am stuck on the same problem. 
> Is Energyplus EMS the only way? Or which 4-5 variables can you adjust?
> Also, what do you mean by not using VAV? I am using an AHU and VAV or not,
> there is the same problem, since you have to use a Setpoint manager for the
> coils.
> 
> It is a very common HVAC configuration, which I cannot find how to
> configure...
> Any idea?
> 
> Regards,
> 
> Germán.
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> , YuanLu Li <yli006@>
> wrote:
> >
> > 
> > If yu do not have pre-heat and reheat and there is not need to use VAV,
> you should not model using VAV. The zone thermostat should be used to
> control the cooling and heating coils directly. When you use VAV dampler,
> the theremostat controls the damper which change the flow rate which results
> in different zone temperature. The process is more complex. You need to
> adjust four or five variables to work together to make the system work.
> ============================In a real VAV system, a computer control system
> is used to control the fan speed. Pressure sensors are also required. Duct
> temperature, diffuser temperature and room temperature are modified to make
> the desission on whaat to do. Dr. Li 
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> <mailto:EnergyPlus_Support%40yahoogroups.com> 
> > From: matthew.sverre.anderson@
> > Date: Thu, 10 Nov 2011 15:13:58 +0000
> > Subject: [EnergyPlus_Support] Heating/Setpoint Controller
> > 
> > Hello Everybody, I have a question that likely (or at least hopefully!)
> has an easy answer and I am simply too foolish to know it.
> > So I have a building which I modeled as a VAV with no reheat, and no
> preheat coil. I want the coils to operate as needed and simply ignore any
> frost warnings. However, I currently have no schedule for either since there
> will be many times during the fall/spring where we might need to heat/cool
> during the same day or during the week. 
> > 
> > The problem I am currently having is that the heating/cooling coils are
> operating year long at the same time. I want the HC to operate when the
> building needs heating, the CC to operate when the building needs cooling
> (neither to operate at the same time). Am I thinking about this incorrectly?
> 
> > 
> > Also is there a way to implement a dead band above/below the set point
> where the system is "satisfied" to prevent the system from "slamming"
> on/off?
> >
>




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