Re: [EnergyPlus_Support] Cooling Tower wetbulb temperature difference control type

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

Comparing the version 1.2.1 and 1.4.0 IDD files, I am not seeing any 
differences in the inputs related to CONDENSER LOOP controls.  You can still 
specify and hourly discharge temperature setpoint using a SET POINT MANAGER:* 
object applying a setpoint to the Condenser Loop Temperature Setpoint Node.

That said, Outdoor Wetbulb Temperature Difference Based Operation does not 
control the tower discharge temperature.  It only determines which towers are 
active at a given temeperature difference.

If I understand correctly, you want to control the tower outlet temperature to 
be fixed offset above the current wet-bulb temperature?  The only way I know to 
do this with current EnergyPlus objects is to create an hourly schedule that 
tracks outdoor wet-bulb plus offset and feed that schedule to a SET POINT 
MANAGER:SCHEDULED object which applies the setpoint to the Condenser Loop 
Temperature Setpoint Node (which is normally the same node as the Condenser 
Side Outlet Node Name).  You can use SCHEDULE:FILE:COMMA to simplify the 
schedule entry.

Mike


On 9 Apr 2007 at 17:49, maenebraska wrote:

> Hello,
> 
> I have setup a cooling tower system on a previous E+ version (1.2.1) 
> and am having trouble getting the same operation to occur in the 
> latest version.
> 
> I would like to have a cooling tower that operates to maintain a 
> disharge water set-point based on the difference b/n outdoor wetbulb 
> temperature and discharge tower water temperature.  I have followed 
> the example file but am still unable to figure out the error issue.  
> A fatal error has occured with respect to (WRT): "Equipment 
> operation list invalid for Wetbulb Diff."  
> 
> Have setup the same trial using wetbulb based control and have found 
> no errors.  The main difference on my file WRT the example is 
> considering the reference node/temperature for the condenser loop.  
> In the previous version I was able to reference the cooling tower 
> discharge temp in place of "AIR or GROUND."  This allows me to 
> specify an hourly set-point for condenser water temperature using a 
> set-point manager.
> 
> Please help with any experience or an example file that I might 
> reference.
> 
> Thank you very much,
> 
> Dan 
> 
> 
> 
> 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
> 
> 
> 
> 
> 


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





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