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Re: [EnergyPlus_Support] Exhaust Fan Operation and Connections



The ZONE EXHAUST FANs are not being simulated because they are not listed in 
the ZONE EQUIPMENT LISTs.  See example file 5ZoneEndUses.idf.  Clearly this 
should result in an error message.  We will work on fixing that for the next 
release.

Mike


On 2 May 2007 at 14:43, asheaffe wrote:

> To All,
> 
> Ah yes, another problem from the troublemakers here at UIC.  
> Sometimes I wonder if Gard has ever considered revoking our EPlus 
> license - I hope there isn't a user idiocy clause in the agreement.  
> Anyhow, I am having trouble setting up exhaust fans.  The short 
> version of the problems is that I cannot get several exhaust fans to 
> operate and pass zone exhaust to the appropriate connected nodes.  
> The file that I am having trouble with is posted as (C2+_19.idf).  
> The problematic exhaust fans are all of the exhaust fans in the 
> file.  The eso states that there is no flow through the fan input 
> nodes and no power consumption by the fans - although the input 
> nodes do correctly report zone temperatures.  The output nodes do 
> show flow, but do not show the correct temperatures.  Any ideas on 
> how to fix this?
> 
> The long version of the problem is that I am trying to model a DOAS 
> system for packaged rooftops where I have one packaged rooftop 
> pretreating ventilation air and delivering that air to the OA intake 
> of the zone packaged rooftops.  The only way that I have been able 
> to think of to make this work is to create associated dummy zones 
> (denoted in the idf as zone names that start with a V) for each real 
> zone so that I can split the flow from the pretreating rooftop using 
> a zone splitter.  To ensure continuity in the Air Primary Loop, the 
> return flows from the dummy zones are mixed and sent back to the 
> pretreating rooftop but not recirculated (the pretreating rooftop is 
> 100% OA).  I supply the pretreated air from each dummy zone through 
> the zone exhaust to the OA intake of the associated real zone 
> packaged unit.  However, as mentioned, the flow and temperature 
> conditions at the exhaust fan inlet and outlet for each fan do not 
> match.  Can this be fixed?  Is there any other way that I can model 
> this system - on rooftop supplying the OA intake of several others?
> 
> I have tried to set up the system without the exhaust fans (a real 
> system of this type wouldn't have them - as such I have set their 
> efficiencies impossibly high and their delta pressures impossibly 
> low to minimize their power consuption), but then I don't have two 
> independent nodes to ensure that the temperature and flow supplied 
> to the zone rooftops is consistent.
> 
> 
> 
> 
> 
> 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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