Re: [EnergyPlus_Support] Zone Equipment List problems

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

This model has an air loop VAV with reheat and radiant hydronic cooling serving 
the same zones, and both system are autosized.

1.  EnergyPlus autosizing does not understand if there is more than one system 
serving the same zone.  It will size both system to meet the full cooling load.

2.  In the input file, the VAV terminal unit is priority 1 for cooling, and the 
radiant hydronic is priority 2.  So, if the VAV unit can meet the thermostat 
setpoint (which it will since it has been autosized), then there is no load 
remaining for the radiant cooling to serve.

3.  So, revsersing the cooling priorities in zone 1N results in the radiant 
hydronic system showing flow, and the VAV box sitting a min flow.

4.  However, in milder weather, the zone will probably overcool due to the min 
flow from the VAV box and the reheat will come on, which is not what you want.  
So, you will probably need to hand size one of both systems in order to share 
the load.  And you need to decide which system should be priority 1 and 2.

Mike


On 6 Sep 2007 at 21:48, eduardcubi wrote:

> Hi all,
> 
> I have some problems when including radiant cooling systems in the
> zone equipment list. 
> It seems that when I assign the systems to their respective zones
> (e.g. "z1N Radiant Ceiling" under "z1N Equipment") these don't work
> (i.e. there is no temperature gain from the inlet to the outlet, and
> the flow rate is 0). However, if I "do a mess" with the assignations,
> it "works" (e.g.  "z1E Radiant Ceiling" under "z1N Equipment").
> 
> I have checked everything I think that may be relevant, but I couldn't
> find the source of the error.
> 
> Could you help me?
> 
> Thanks a lot,
> 
> Eduard
> 
> P.S. I have updated the file: "newtest.idf"
> 
> 
> 
> 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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