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Re: [EnergyPlus_Support] Simultaneous heating and cooling in RTU


That made the trick. I was trying to set the temperature after the heating coil and after the cooling coil. I just copied the node referenced in the SetpointManager:Scheduled and it worked. Thanks a lot.
The only problem I have now is that the mixed air is still trying to reach the cooling setpoint even in the winter.
I guess I can live with that, but if you know how to remedy that, I'm definitely interested.
Best,
Julien
Le 10 juin 2014 à 15:22, annie <mailto:anniemarston@xxxxxxxxxxx>anniemarston@xxxxxxxxxxx [EnergyPlus_Support] <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> a écrit :
> 
> I can take a look at your file if you like. Make sure you are filling in the node name of the heating or cooling coil you are trying to control. The air outlet node is the one that should work, or exactly the name from the setpoint scheduled that was used before. You need a setpoint for both the heating and the cooling coil. The mixed air setpoint should be unaffected, that should stay the same as before. The only change that needs to be made from the original, is to delete the setpointManager:scheduled for the coils you want to change and put the same coil node names (the air outlet node) into the multizone setpoint manager. Make sure you have the correct air loop connected to the the setpoints also. If you don't want to post the file here my email address is<mailto:a.marston@xxxxxxxxxxxxxx>a.marston@xxxxxxxxxxxxxx.
> Annie
> 
> To: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
> From: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
> Date: Tue, 10 Jun 2014 15:06:03 -0400
> Subject: Re: [EnergyPlus_Support] Simultaneous heating and cooling in RTU
> 
>  
> Annie,
> 
> I've tried three different ways of integrating those, but I'm always getting an error, that I'm missing a temperature setpoint for either the heating/cooling coils or the Mixed Air.
> 
> I tried looking in the example files that came with E+ but didn't find a situation where the Multizone setpointmanagers were used (aside from a humidity one but that didn't help). 
> 
> Would you happen to have such an example file you could send me?
> 
> Thanks for your help,
> Julien
--
> Julien Marrec, EBCP, BPI MFBA
> Ingénieur en efficacité énergétique du bâtiment
> T: +33 6 95 14 42 13
> 
> LinkedIn (en) : <http://www.linkedin.com/in/julienmarrec>www.linkedin.com/in/julienmarrec
> 
> 2014-06-10 13:52 GMT-04:00 annie <mailto:anniemarston@xxxxxxxxxxx>anniemarston@xxxxxxxxxxx [EnergyPlus_Support] <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx>:
>>  
>> Yes those are the setpoints I was referring too. I haven't used SetpointManager:Scheduled:DualSetpoint but taking a quick look at the i/o reference manual it looks like this is a setpoint used for plant loops
>> "SetpointManager:Scheduled:DualSetpoint
This setpoint manager places a high and low schedule value on one or more nodes. The
input consists of the Setpoint Manager name, the control variable, the high and low set point
schedule names, and the name of a node list. The node list contains the name of those
nodes at which the setpoint is to be applied. Of course, a node list name can simply be the
name of a single node. Currently the DualSetpoint Manager will be used with PlantLoop when
the Plant Loop Demand Calculation Scheme is set to “DualSetpointDeadband”."
>> So it might not be relevant or work for your situation. I would advise the multizone setpoint managers, but I am comfortable with these and know how they work so I am biased. You can always put a setpoint in for one of your AHUs run the simulation for a few days and output the node temperatures to see if the control is doing what you want it to.
>> Annie
>> 
>> 
>> 
>> To: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
>> From: <mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx
>> Date: Tue, 10 Jun 2014 12:10:21 -0400
>> Subject: Re: [EnergyPlus_Support] Simultaneous heating and cooling in RTU
>> 
>>  
>> Annie,
>> 
>> Thanks for your answer.
>> 
>> I did think about setting the discharge temperature the same and letting the reheat coil do the rest, but this is for a LEED "proposed" model and my mechanical specs do show a different discharge temperature for heating and cooling coils.
>> 
>> The setpoint managers you are referring to are SetpointManager:MultiZone:Cooling:Average and SetpointManager:MultiZone:Heating:Average, aren't they?
>> Would SetpointManager:Scheduled:DualSetpoint work too?
>> 
>> Thanks a lot,
>> Julien
>> 
>> 
>> --
>> Julien Marrec, EBCP, BPI MFBA
>> Ingénieur en efficacité énergétique du bâtiment
>> T: +33 6 95 14 42 13
>> <http://www.julienmarrec.com/>>> www.julienmarrec.com
>> 
>> DoYouBuzz : <http://www.doyoubuzz.com/julien-marrec_1>www.doyoubuzz.com/julien-marrec_1
>> LinkedIn (fr) : <http://www.linkedin.com/in/julienmarrec/fr>www.linkedin.com/in/julienmarrec/fr
>> LinkedIn (en) : <http://www.linkedin.com/in/julienmarrec>www.linkedin.com/in/julienmarrec
>> 
>> 2014-06-09 20:48 GMT-04:00 annie <mailto:anniemarston@xxxxxxxxxxx>anniemarston@xxxxxxxxxxx [EnergyPlus_Support] <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx>:
>>>  
>>> Hi,
>>> You can set your heating coil to the same temperature output as your cooling coil and then let the reheat deal with the rest, you will still get simultaneous heating and cooling but it will be at the reheat now so only for some zones. 
>>> The second thing you can do is to use a multizone set point. This allows you to set two temperatures a lower and a higher temperature on each coil. The coils will adjust to what is requested by the zones. There are two types you can set it by one zone which controls everything or you can set it on an average return temperature. Take a look at the setpoint mangers these are the controls that you need there names are fairly self explanatory the input output reference will fill in any gaps.
>>> I hope this helps
Annie
>>> 
>>> Sent from my iPhone
>>> On Jun 9, 2014, at 4:03 PM, "Julien Marrec <mailto:julien.marrec@xxxxxxxxx>julien.marrec@xxxxxxxxx [EnergyPlus_Support]" <<mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx>EnergyPlus_Support@xxxxxxxxxxxxxxx> wrote:
>>> 
>>>>  
>>>> Hi everyone,
>>>> 
>>>> I've inherited an E+ energy model, and I'm experiencing a problem of simultaneous heating and cooling in a rooftop unit.
>>>> 
>>>> The RTU has: mixing box > cooling coil > heating coil > supply fan.
>>>> 
>>>> It then serves multiple VAV boxes with reheat (no cooling coil).
>>>> 
>>>> I'm trying to set a discharge temperature of 55°F when in cooling mode and 75°F when in heating mode. The spaces served have a Tstat of 77°F in cooling mode and 65°F in heating mode.
>>>> 
>>>> Currently, I'm seeing that, at all times (winter or summer), the mixed air is trying to meet 55°F (due to SetpointManager:MixedAir), if above it is cooled to 55°F and then reheated to 75°F.
>>>> 
>>>> I clearly have a controls problem.
>>>> 
>>>> Right now, there are two SetpointManager:Scheduled for the RTU: one is controlling the temperature after the cooling coil (setpoint of 55°F), and the other is controlling the temperature after the heating coil (setpoint of 75°F).
>>>> I also have two setpointmanager:Mixed air: one on cooling for the mixed air and one of heating for the supply temperature.
>>>> 
>>>> SetpointManager:Scheduled,
>>>>     RTU 1 Cooling Supply Air Temp Manager,  !- Name
>>>>     Temperature,             !- Control Variable
>>>>     Always 13.89C or 57F,    !- Schedule Name
>>>>     RTU 1 Supply Fan Outlet; !- Setpoint Node or NodeList Name
>>>> 
>>>> SetpointManager:Scheduled,
>>>>     RTU 1 Heating Supply Air Temp Manager,  !- Name
>>>>     Temperature,             !- Control Variable
>>>>     Always 24.72C or 76.5F,  !- Schedule Name
>>>>     RTU 1 Supply Path Inlet; !- Setpoint Node or NodeList Name
>>>>     
>>>>     
>>>> SetpointManager:MixedAir,
>>>>     RTU 1 Cooling Coil Air Temp Manager,  !- Name
>>>>     Temperature,             !- Control Variable
>>>>     RTU 1 Supply Fan Outlet, !- Reference Setpoint Node Name
>>>>     RTU 1 Heating Coil Outlet,  !- Fan Inlet Node Name
>>>>     RTU 1 Supply Fan Outlet, !- Fan Outlet Node Name
>>>>     RTU 1 Mixed Air Nodes;   !- Setpoint Node or NodeList Name
>>>> 
>>>> (RTU 1 Mixed Air Nodes = RTU 1 Cooling Coil Outlet + RTU 1 Mixed Air Outlet)
>>>> 
>>>> SetpointManager:MixedAir,
>>>>     RTU 1 Heating Coil Air Temp Manager,  !- Name
>>>>     Temperature,             !- Control Variable
>>>>     RTU 1 Supply Path Inlet, !- Reference Setpoint Node Name
>>>>     RTU 1 Heating Coil Outlet,  !- Fan Inlet Node Name
>>>>     RTU 1 Supply Fan Outlet, !- Fan Outlet Node Name
>>>>     RTU 1 Heating Coil Outlet;  !- Setpoint Node or NodeList Name
>>>> 
>>>> 
>>>> I'm wondering how I can properly set my controls to make sure I don't have simultaneous heating and cooling. I've thought about simply switching the coils, so that the heating coil is put before the cooling one, but there must be another way (and it would still try to meet 55°F in winter mode for the mixed air).
>>>> 
>>>> I must admit that I'm lost between all the setpointmanagers, availabilitymanagers, etc, so any help will be greatly appreciated.
>>>> 
>>>> Thanks,
Julien
>>>> --
>>>> Julien Marrec, EBCP, BPI MFBA
>>>> Energy And Sustainability Engineer
>>>> T: +33 6 95 14 42 13
>>>> 
>>>> LinkedIn (en) : <http://www.linkedin.com/in/julienmarrec>www.linkedin.com/in/julienmarrec
>>> 
>> 
>> 
> 
> 
> 




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 Posted by: Julien MARREC <julien.marrec@xxxxxxxxx>

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