Re: [EnergyPlus_Support] Constant Flow Ventilation Setback based on ODB

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

As you probably realize, there is not a straightforward way to accomplish this. 
 Some questions for you:  

What EnergyPlus system type are you using?  

Does this system serve more than one zone?  

Do you need to change the system supply flow rate, or just change the outside 
air flow rate (changing the outside air fraction) keeping the total supply flow 
constant?

Is this ventilation air conditioned before it enters the zone(s)?

Depending on the answers to the above question, some possible ways to control 
this might be


SYSTEM AVAILABILITY MANAGER:LOW TEMPERATURE TURN OFF
or SYSTEM AVAILABILITY MANAGER:HIGH TEMPERATURE TURN ON
If the ventilation air can be provided in two parts, by two different systems, 
then one of these availability managers might be used to shut off one system at 
cold outdoor temperatures.

SCHEDULE:FILE:COMMA could be used to import a schedule built in a spreadsheet 
that has one value when ODB<=-10C and another value when ODB>-10C.  This 
schedule could possibly be fed to an availability manager or a min outside air 
schedule.

Mike



On 17 Mar 2007 at 9:52, elizabeth.ricker wrote:

> Hello,
>    I am currently modeling a ventilation system with a constant 
> volumetric flow rate.  I would like to be able to control this flow 
> rate according to the temperature of the incoming outdoor air. This 
> means that flow rate should be halved when the outdoor temperature 
> drops below -10C.  Is there a simple way to do this?  Perhaps with a 
> controller or a schedule of some kind?  I have looked through the 
> EnergyPlus documentation, but have yet to find a "simple" solution.  
> Any suggestions?  
> 
> Thanks,
> 
> Betsy
> 
> 
> 
> 
> 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.idf 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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