Re: [EnergyPlus_Support] Return Air Setpoint Control Strategy

[Jose Coutinho <coutinho@xxxxxxxxx>]

Thanks a lot Mike,

However, from the I/O manual, It looks that CONTROL objects that actuate
on Air Loop coils can not sense setpoints at nodes that are located
downstream after the Zone Equipment subloop. Is this correct? If it is
so, solutions 1-3 are not possible to implement. Actually, your first
suggestion is exactly what I tried to model on the first hand.

Anyway, thanks again for your suggestions. After all, it is always
important to realize that we are thinking the right way.

Cheers.
Jose'



Michael J. Witte wrote:
> 
> 
> 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:
>> http://www.energyplus.gov <http://www.energyplus.gov>
>>
>> The group web site is:
>> http://groups.yahoo.com/group/EnergyPlus_Support/
> <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.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 <mailto:EnergyPlus-Support%40gard.com>
> 
> 


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.pdf under the Documentation link and press the "search" button.
 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/

<*> Your email settings:
    Individual Email | Traditional

<*> To change settings online go to:
    http://groups.yahoo.com/group/EnergyPlus_Support/join
    (Yahoo! ID required)

<*> To change settings via email:
    mailto:EnergyPlus_Support-digest@xxxxxxxxxxxxxxx 
    mailto:EnergyPlus_Support-fullfeatured@xxxxxxxxxxxxxxx

<*> To unsubscribe from this group, send an email to:
    EnergyPlus_Support-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/