[EnergyPlus_Support] Re: Variable Speed Fan

["Elreq" <tolteca33@xxxxxxxxx>]

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, "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, "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, "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, "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, "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, "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.
> > > > > >
> > > > >
> > > >
> > >
> >
>



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