Re: [EnergyPlus_Support] can't meet demand?

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

SINGLE DUCT:VAV:NOREHEAT will modulate from minimum flow to full flow when 
there is a demand for cooling.  When there is a demand for heating, it will 
deliver minimum flow at the specified supply air temperature.  It has no way of 
controlling the heating output.  To control heating outpu with such a system, 
you would need to vary the supply air temperature using SET POINT 
MANAGER:COLDEST.  If full flow at 4C is not enough to cool the zone, then the 
maximum air flow rate is too low.  Or the cooling coil may be too small to 
deliver the specified supply air temperature.  Report "System Node Temp" and 
"System Node Setpoint Temp" to monitor this.  Are you autosizing the flow rates 
and capacities?  If not, see 5ZoneAuto in the ExampleFiles folder to see how.

Mike


On 8 Dec 2004, at 11:44, hbn_pch wrote:

> 
> 
> Hi,
>   I've run a simulation.I set the thermostic setpoint temp at 21.1
> (heating) and 23.9(cooling).Since i use the single 
> duct:vav:noreheat,i set the supply air temp setpoint at 26(winter) 
> and 12(summer).i found the zone temp is bigger a lot than thermostic 
> setpoint while heating(21.1);but the zone temp can't reduce in summer.
> 
> So i vary the supply air temp setpoint at 4 in summer.Then the zone 
> temp can reduce but is much bigger than thermostic setpoint temp
> (23.9).i'am puzzled.How can i adjust it to meet the demand?Can l 
> adjust by varying supply air temp?If not,what should i vary?
> 
> I've upload my idf.zip.Appreciated your help.
> 
> Thanks.
> pch
> 
> 
> 
> 
> 
> 
> 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.
> 
> Yahoo! Groups Links
> 
> 
> 
> 
> 
> 
> 
> 
> 



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




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