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[EnergyPlus_Support] Re: Variable Speed Fan
Many Thanks.
But I see that the Coil:DX: MultiSpeed:Cooling (and also Heating) can
only be referenced by a Unitary System MultiSpeed Heat Pump air to
air. The problem is that I do not want to include any coils in my
model, just mechanical ventilation. Is there a way to set the coils
capacity to zero, in such a way that the air is only passing through
it without warming up or cooling down?
I would like to make it more simple. Until now I can make variations
on the amount of outside air coming in, but the fan is running always
at the same capacity, so I suppose it mixes the return air in the OA
mixer in such a way that the incoming volume is always constant. So I
am sure there must be a way to make the supply fan have 3 different
speeds without having to introduce a coil and a heat pump. I will keep
on searching and also waiting for suggestions or comments.
Rgds,
Santiago
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad
<RRaustad@...> wrote:
>
> See documentation for Coil:DX:MultiSpeed:Cooling and
> Coil:DX:MultiSpeed:Heating.
>
> Elreq wrote:
> >
> > I want to simulate a typical 3-speed variable fan, for example, 100%,
> > 66% and 33% of its nominal capacity.
> >
> > That is: option B)
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "JV Dirkes II"
<jvd2pe@>
> > wrote:
> > >
> > > Dear Santiago,
> > >
> > > I am still not clear about what you are trying to accomplish. Do you
> > > want to model:
> > > a) a fan which operates at many speeds, proportional to the
heating /
> > > cooling load?
> > > b) or a fan which operates at 2 or 3 discrete speeds, for example --
> > > 100% and 50% of capacity?
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "Elreq"
<tolteca33@> wrote:
> > > >
> > > > Dear Forum
> > > >
> > > > I still cannot make the variable fan to run at different
speeds. Does
> > > > anybody has an example where this happens? Maybe if I take a
look I
> > > > can see what I am missing.
> > > >
> > > > Regards
> > > >
> > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "jvd2pe" <jvd2pe@>
wrote:
> > > > >
> > > > > Dear Elreq,
> > > > >
> > > > > Assuming that you are using one of the constant volume fan
> > objects....
> > > > >
> > > > > Constant volume and constant pressure = constant power.
> > > > >
> > > > > Normally, the variation in outdoor air is accomplished by a
> > mixing box
> > > > > ("Mixer" object in E+), which just adjusts the ratio of
outdoor and
> > > > > return airflows.
> > > > >
> > > > > If you are using a variable volume fan, something is forcing th
> > fan to
> > > > > remain at constant volume.
> > > > >
> > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "Elreq" <tolteca33@>
> > wrote:
> > > > > >
> > > > > > Thanks for the recommendation but I obviously read all this.
> > > > > >
> > > > > > Now I have a big question because I have created a schedule
> > for the
> > > > > > minimum outside air flow, depending on the occupancy, and
in the
> > > > > > results it clearly shows that the air changes per hour on each
> > > zone is
> > > > > > not constant anymore, being higher in the hours of occupancy,
> > > but the
> > > > > > supply fan, that is supposed to provide this outside air, is
> > always
> > > > > > running at the same power. So I dont know how is possible that
> > > the air
> > > > > > flow is changing but the fan is always running at the same
speed.
> > > > > >
> > > > > > Any suggestions greatly appreciated.
> > > > > >
> > > > > > Santiago.
> > > > > >
> > > > > >
> > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "JV Dirkes II"
> > <jvd2pe@>
> > > > > > wrote:
> > > > > > >
> > > > > > > Dear Elreq,
> > > > > > > I recommend that you review the Input Output Reference,
> > > starting at
> > > > > > > page 1162. Several fans are discussed. In short:
> > > > > > > Fan:Simple:Const Volume is a constant volume, continuous
> > > > operation fan
> > > > > > > which can be turned on and off via a schedule.
> > > > > > > Fan:Simple:OnOff is similar to the one above, but it cycles
> > > > itself on
> > > > > > > and off as required by its thermostat ... all during the
> > scheduled
> > > > > > > operation period. This is a typical mode of operation for a
> > home
> > > > > > furnace.
> > > > > > > Fan:Simple:Variable Volume runs continuously during the
Schedule
> > > > > > > period, but varies its volume to meet the heating or cooling
> > > demand.
> > > > > > >
> > > > > > > I hope that this is helpful!
> > > > > > >
> > > > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>, "Elreq" <tolteca33@>
> > > > wrote:
> > > > > > > >
> > > > > > > > Dear Forum,
> > > > > > > >
> > > > > > > > I am simulating a typical house with balanced
ventilation and
> > > > > > > > baseboard heating units. I want that the supply fan of
the Air
> > > > Loop
> > > > > > > > has three different speeds, so I introduce the fan
> > coefficients
> > > > > > > > mentioned in the input output reference that
correspond to the
> > > > > > > > variable speed motor. The problem is that the fan is
constant
> > > > > all the
> > > > > > > > time at a constant speed. Could somebody tell me how
to make
> > > > it work
> > > > > > > > as a variable speed fan?
> > > > > > > >
> > > > > > > > Many thanks.
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> >
>
> --
> 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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