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[EnergyPlus_Support] Re: Demand Ventilation Control and Enthalpy Wheel
So what happens currently when the bounds are exceeded? Does the wheel turn off? I could live with that.
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <RRaustad@...> wrote:
>
> This issue has come up many times in the past. The manufacturer cannot
> guaranteethe ratings of the HX when the flow rate ratio is <50% or >130%
> of design. It's as simple as that. And there was no guidance of what to
> do inside the model when the air flow ratio was out of bounds since even
> the manufacturer could not tell us. If you want to use this HX model,
> keep the air flow ratio within the boundaries of where the model is
> valid. Otherwise, change to a flat plate HX (no latent heat transfer).
>
> On 11/1/2011 4:04 PM, Jean marais wrote:
> >
> > Had exactly the same issue doing exactly the same thing for the summer
> > case. I don't know any way to suppress warnings. Obviously, the amount
> > of heat exchange at the enthalpy wheel reduces to very small amounts
> > when the flow from exhaust is <50% the supply side. It seemed as if
> > the wheel stopped working, when I watched the outputs, but I actually
> > have no idea how the object is programmed to react in these
> > conditions. PS in the project I was simulating, an evapourative cooler
> > was cooling the exhaust air (but making very moist) before the
> > heatwheel to increase (take advantage) the sensible heat transfer
> > (which is at about 70%, while the latent eff is only 30% therefore not
> > missing much by "humidifying" the air).
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, Jason Kirkpatrick
> > <jason.alan.kirkpatrick@> wrote:
> > >
> > > All,
> > >
> > > I have a model including demand controlled ventilation and an enthalpy
> > > wheel treating the ventilation before the AHU. This all works ok,
> > but since
> > > the ventilation is varying with the occupancy, the enthalpy wheel
> > gives an
> > > error that the ventilation flowrate is too far from the design flowrate:
> > >
> > > ************* ** Warning ** HeatExchanger:AirToAir:SensibleAndLatent
> > > "F1:AHU HEAT RECOVERY": Average air volume flow rate is <50% or >130%
> > > warning continues. Air flow rate ratio statistics follow.
> > >
> > > I am wondering if there is a way that anyone knows of circumventing this
> > > warning or at least suppressing it.
> > >
> > > Thanks,
> > >
> > > Jason
> > >
> >
> >
>
> --
> 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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