Re: [EnergyPlus_Support] Return Air Setpoint Control Strategy

["Michael J. Witte" <mjwitte@xxxxxxxx>]

This is not a supported control strategy in EnergyPlus, but I will add it to 
the suggested enhancement list.

Here are some approaches you could try, but I do not know if they will work.

1.  Use SET POINT MANAGER:SCHEDULED to place the desired return air control 
temperature as a setpoint on the Air Loop Inlet Node.  In the CONTROLLER:SIMPLE 
object for the cooling coil, set the Control_Node to be the Air Loop Inlet 
Node.

2.  Same as 1, but use the ZoneEquipGroup Outlet Node instead of the Air Loop 
Inlet Node.  These nodes both represent the same physical point in the system, 
but they are updated at different times in the iteration sequence, so you might 
find one to behave better than the other.

3.  Use SET POINT MANAGER:WARMEST to place a setpoint on the cooling coil air 
outlet node, and set the controller control node to that node.  If this is a 
draw-thru system, then place this setopint at the fan outlet and use a SET 
POINT MANAGER:MIXED AIR to place an adjusted setpoint at the cooling coil air 
outlet node.

4.  Choose the dominant zone on the system and use it to control the supply air 
temperature with SET POINT MANAGER:SINGLE ZONE COOLING.

Note - whatever approach you use, be sure to set the cooling priority (in the 
ZONE EQUIPMENT LIST) for the DIRECT AIR units to be 1, and the unit vents to be 
cooling priority 2.

Mike


On 7 Apr 2007 at 11:31, coutinho301272 wrote:

> Dear All,
> I have several zones served by a single constant volume AHU (cooling 
> only) plus individual cooling unitvents on each zone. The air system 
> has cooling prioriry over the UnitVents and provides fresh air. 
> UnitVents will complement cooling needs on each zone.
> 
> I wonder how can I control water flow rate in the central cooling coil 
> based on return air temperature, ie, by setting a target temperature at 
> the Air Loop Inlet Node.
> 
> Thanks a lot in advance,
> Jose'
> 
> 
> 
> 
> The primary EnergyPlus web site is found at:
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> 
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> 
> 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.pdf under the
> Documentation link and press the "search" button.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 


========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support      
EnergyPlus-Support@xxxxxxxx





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