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[EnergyPlus_Support] Re: Help with override error
Thanks Richard,
Manuel sizing does the trick.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <RRaustad@...> wrote:
>
> It's telling you that the design parameters do not conform with
> psychrometrics. Usually, design values for water-side and air-side are
> 5.5C and 11.1C, respectively. Your air-side delta T does not provide
> this value. Now you can operate at a supply air temperature of 18C if
> you like, but you should "size" the coil differently. As the message
> states, I would change the sizing information accordingly. I have tried
> this and it still leads to the same error, hopefully this won't happen
> to you. So I am not exactly sure if the error will disappear without
> some iteration.
>
> If you do want to size your coil for an exiting air temperature of 18C
> at this air flow, entering air condition, and water temp/flow rate, then
> you will have to manually size the coil to get there.
>
> The amount of reheat you use will depend on the supply air temperature
> (your 18C) and flow rate vs the zone loads. You can also reset the
> supply air temperature based on outdoor temperature
> (SetpointManager:OutdoorAirReset) to help reduce the amount of reheat.
>
> On 7/29/2011 10:38 AM, Jean marais wrote:
> >
> > I have the following error:
> >
> > ************* Beginning System Sizing Calculations
> > ************* Beginning Plant Sizing Calculations
> > ** Warning ** In calculating the design coil UA for Coil:Cooling:Water
> > DOAS COOLING COIL
> > ** ~~~ ** the apparatus dew-point is below the coil design inlet water
> > temperature;
> > ** ~~~ ** the coil bypass factor is unrealistically large;
> > ** ~~~ ** the coil outlet design conditions will be changed to correct
> > the problem.
> > ** ~~~ ** The initial design conditions are: Tair,in = 24.4500
> > ** ~~~ ** Wair,in = 9.478796E-003
> > ** ~~~ ** Twater,in = 6.0000
> > ** ~~~ ** Tair,out = 18.0000
> > ** ~~~ ** Wair,out = 8.000000E-003
> > ** ~~~ ** The revised design conditions are: Tair,out = 14.5987
> > ** ~~~ ** Wair,out = 9.371939E-003
> >
> > All my coil inputs possible are autosized. Zone and System humidity
> > designs are 0.008 (default). My outlet Tair design is 18 deg (as seen
> > in the error msg.)
> >
> > 1) What is going on here exactly?
> > 2) How can I enter other parameters so that the error does not occur
> > and no reheat is nessesary.
> >
> >
>
> --
> Richard A. Raustad
> Senior Research Engineer
> Florida Solar Energy Center
> University of Central Florida
> 1679 Clearlake Road
> Cocoa, FL 32922-5703
> Phone: (321) 638-1454
> Fax: (321) 638-1439 or 1010
> Visit our web site at: http://www.fsec.ucf.edu
>
> UCF - From Promise to Prominence: Celebrating 40 Years
>
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