[EnergyPlus_Support] Re: Problems in maintaining humidity control

["elmofuddly" <elmofuddly@xxxxxxxxx>]

Hello,

I've manually increased the flowrate in the `sizing' objects (or 
specifically, in the zone sizing object). This has had the desired 
effect over the humidity (and by association the setpoint node's 
fluctuations have levelled out). Thanks very much. 

I would like to ask a follow up question if I may; is there 
something wrong in my input that didn't allow EnergyPlus to autosize 
a larger volumetric flowrate to offset this problem before my manual 
input?

Also, I am getting too much fresh air in the summer design day (I 
would like a minimum intake but I seem to be getting maximum 
intake). I have scheduled a minOA Sched in the OA controller, 
however it does not seem to take effect here. The winter OA intake 
works fine, does this flag anything in particular?

Kind regards

-Elmer


--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Michael J. Witte" 
<mjwitte@g...> wrote:

> When using humidity control on the central chilled water coil, the 
controller 
> changes the chilled water setpoint to provide the required 
humidity ratio 
> needed to meet the humidistat setpoint.  The varying setpoint 
values reflect 
> the adjusted setpoints for humidity control.  Given the low 
numbers being seen, 
> it appears that the airflow rates are not adequate to meet the 
humidity loads?
> 
> Mike
> 
> 
> On 18 Feb 2005, at 8:25, Elmer Morrissey wrote:
> 
> > 
> > 
> > Hello all,
> > 
> > 
> > 
> > I am wondering if anyone has any experience in modelling VAV 
systems that
> > maintain strict control over temperature AND humidity in a zone.
> > 
> > 
> > 
> > I am modelling an AHU that provides air to two interior zones in 
an art gallery.
> > I cannot seem to force the system to maintain control over the 
zones over a 24hr
> > period as required by the Art Gallery. 
> > 
> > 
> > 
> > One of my major problems that I have found is a floating 
setpoint on my VAV
> > system outlet node. During the winter, the setpoint output on 
the csv emulates
> > the idf input, however during the summer design day, the csv 
output for the
> > setpoint value floats from ?57oC to 3oC. I cannot seem to locate 
the source of
> > this error as I have no errors or warning. It is scheduled to a 
set value of
> > 17.5oC during the summer and 16oC during the winter. I also have 
trouble
> > stipulating the flow using the sizing objects, they seem to be 
ignored but I am
> > guess this is due to an error elsewhere in the idf.
> > 
> > 
> > 
> > I have uploaded the file to the yahoo page? 
AHU3_AirLoop_PurchasedPlant_V1.idf
> > 
> > 
> > 
> > I would appreciate anyone's experience or advice with this 
matter.
> > 
> > 
> > 
> > Kind regards
> > 
> > 
> > 
> > -Elmer Morrissey
> > 
> > 
> > PhD Researcher, IRUSE, NUIC, Ireland.
> > 
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> > 
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