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, 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
> 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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