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[EnergyPlus_Support] Re: Generating input for SOLAR COLLECTOR PARAMETERS:FLAT PLATE
Can anyone answer this question?
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Elmer Morrissey"
<elmofuddly@...> wrote:
>
> Hi Peter,
>
> Once again, thank you for the reply. My final question (I hope)
for
> my solar loop is a logic question. I am trying to emulate control
on
> the solar loop which also contain heat exchanger which preheats
> water into the source side of a heat pump (which increases the
> efficiency of a heat pump).
>
> The solar system will generate heat which will provide hot water
in
> the domestic hot water pre-heat cylinders. When the cylinder
> temperature is higher than the loop temperature the water will be
> diverted to a plat heat exchanger which will pre-heat the aquifer
> water before it enters the heat pump.
>
> Is there a means of setting this kind of control in E+
>
> Kind regards
>
> -Elmer
>
>
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ellis, Peter"
> <peter_ellis@n...> wrote:
> >
> >
> > Hi Elmer,
> >
> > I do not know what differences in results you might expect when
> substituting water for glycol. We have that problem in general
for
> any plant loop, not just solar collector loops. Perhaps someone
> else on the list has an idea.
> >
> > For a BRANCH, there should technically be only one component
that
> is ACTIVE. This indicates which component will try to regulate
the
> flow through the BRANCH. However, with solar collectors, they are
> fairly dumb; all they can do is request their maximum flow rate
(see
> the Maximum Volumetric Flow Rate field in SOLAR COLLECTOR:FLAT
> PLATE). The system may or may not actually meet this flow rate.
> Since it looks like all of your collectors on the BRANCH are
> identical models, then they presumably all have the same maximum
> flow rate. Therefore, it doesn't matter which one is ACTIVE.
> EnergyPlus may even let you set all of the collectors to ACTIVE,
but
> it might throw an error in that case, I don't know.
> >
> > If you look at the InputOutputReference, you'll see that the
Gross
> Area is mainly for reference and is not used in any calculation.
> The actual surface area of the associated SURFACE:HEATTRANSFER
> object is what is used in the calculation. Whether you choose to
> make your surface area match the "useful area" or the gross area,
> depends on the manufacturer's testing assumptions. Here in the
US,
> we have ANSI/ASHRAE Standard 96 which clearly specifies that the
> gross area should be used for the efficiency and performance
> calculations. I might double-check with the manufacturer, but
> probably it is gross area.
> >
> > P
> >
> >
> > -----Original Message-----
> > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]On Behalf Of Elmer
> Morrissey
> > Sent: Wednesday, January 11, 2006 10:06 AM
> > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > Subject: [EnergyPlus_Support] Re: Generating input for SOLAR
> COLLECTOR PARAMETERS:FLAT PLATE
> >
> >
> > Hi Peter,
> >
> > Thank you kindly for the detailed replies.
> >
> > Is there a large mismatch in the results when substituting water
> > circuits and for glycol circuits? Do you know of any
documentation
> > that details the difference in performance characteristics?
> >
> > If I have several solar arrays circuits that are in parallel.
And
> if
> > within these circuits, individual solar arrays are connected in
> > series, are these all assumed to be ACTIVE within the branch
lists?
> >
> > e.g. is the following correct...
> >
> > BRANCH,
> > Vitosol 100 SW Branch, !- Branch Name
> > 0,
> > SOLAR COLLECTOR:FLAT PLATE,
> > Vitosol 100 SW No1/6 Collector,
> > Vitosol 100 SW No1/6 Collector Inlet Node,
> > Vitosol 100 SW No1/6 Collector Outlet Node,
> > ACTIVE, !- Comp1 Branch Control Type
> > SOLAR COLLECTOR:FLAT PLATE,
> > Vitosol 100 SW No2/6 Collector,
> > Vitosol 100 SW No1/6 Collector Outlet Node,
> > Vitosol 100 SW No2/6 Collector Outlet Node,
> > ACTIVE,
> > SOLAR COLLECTOR:FLAT PLATE,
> > Vitosol 100 SW No3/6 Collector,
> > Vitosol 100 SW No2/6 Collector Outlet Node,
> > Vitosol 100 SW No3/6 Collector Outlet Node,
> > ACTIVE,
> > SOLAR COLLECTOR:FLAT PLATE,
> > Vitosol 100 SW No4/6 Collector,
> > Vitosol 100 SW No3/6 Collector Outlet Node,
> > Vitosol 100 SW No4/6 Collector Outlet Node,
> > ACTIVE,
> > SOLAR COLLECTOR:FLAT PLATE,
> > Vitosol 100 SW No5/6 Collector,
> > Vitosol 100 SW No4/6 Collector Outlet Node,
> > Vitosol 100 SW No5/6 Collector Outlet Node,
> > ACTIVE,
> > SOLAR COLLECTOR:FLAT PLATE,
> > Vitosol 100 SW No6/6 Collector,
> > Vitosol 100 SW No5/6 Collector Outlet Node,
> > Vitosol 100 SW No6/6 Collector Outlet Node,
> > ACTIVE;
> >
> > Finally, I have a question about the input field for `gross
area'
> in
> > SOLAR COLLECTOR PARAMETERS:FLAT PLATE. Should this be the area
of
> > the panel that contains `useful' interaction with solar levels
> (i.e.
> > collector area)?
> >
> > Kind regards
> >
> > -Elmer
> >
> >
> >
> >
> > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, "Ellis, Peter"
> > <peter_ellis@n...> wrote:
> > >
> > >
> > > Elmer,
> > >
> > > (a) Test Fluid
> > > The only option for EnergyPlus right now is WATER. If the
> > collector is a solar hot water panel, then most likely is was
> tested
> > using water as the test fluid, unless the manufacturer specified
> > otherwise. We cannot yet model a glycol mixture in the solar
loop
> > (or any loop in EnergyPlus), so you must assume that is water.
> > >
> > >
> > > (b) Test Volumetric Flow Rate {m3/s}
> > > This is the flow rate condition under which the performance of
> the
> > collector was tested by the manufacturer. The efficiency
> > coefficients (d)-(f) are calculated for this specific flow
rate.
> > The flow rate should be indicated somewhere by the manufacturer,
> > maybe called "nominal flow rate" or "recommended flow rate"? If
> > not, try to ask the manufacturer.
> > >
> > >
> > > (c) Test Correlation Type
> > > This indicates whether the collector efficiency curve is
> > correlated according to the INLET fluid temperature (Tin), the
> > OUTLET fluid temperature (Tout), or the AVERAGE of inlet and
> outlet
> > (Tavg). So basically you have to figure out if the "dt" in the
> > manufacturer's equation is:
> > >
> > > dt = Tin-Tair
> > > dt = Tout-Tair
> > > dt = Tavg-Tair
> > >
> > > In the US the INLET correlation is the norm, but this may be
> > different in Europe (thus the ability to choose).
> > >
> > >
> > > (d)-(f)
> > > The efficiency equation that you describe from the
manufacturer
> > can be found in the EnergyPlus EngineeringReference.pdf, and
> appears
> > as follows:
> > >
> > > n = c0 + c1*(Tin-Tair)/Isolar + c2*(Tin-Tair)^2/Isolar
> > >
> > > The manufacturer's coefficients are therefore related in this
> way:
> > > (d) Coefficient 1 of Efficiency Equation (Y-Intercept)
> > {dimensionless}
> > > c0 = n0
> > >
> > > (e) Coefficient 2 of Efficiency Equation (1st Order) {W/m2-K}
> > > c1 = -k1
> > >
> > > (f) Coefficient 3 of Efficiency Equation (2nd Order) {W/m2-K2}
> > > c2 = -k2
> > >
> > >
> > > (g) Coefficient 2 of Incident Angle Modifier (1st Order)
> > > (h) Coefficient 3 of Incident Angle Modifier (2nd Order)
> > > These are usually provided by the manufacturer. I don't know
> what
> > to tell you if you don't have them. Try to ask the
manufacturer.
> > Setting
> > >
> > > Good luck,
> > >
> > > P
> > >
> > >
> > > -----Original Message-----
> > > From: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > [mailto:EnergyPlus_Support@xxxxxxxxxxxxxxx]On Behalf Of Elmer
> > Morrissey
> > > Sent: Tuesday, January 10, 2006 10:57 AM
> > > To: EnergyPlus_Support@xxxxxxxxxxxxxxx
> > > Subject: [EnergyPlus_Support] Generating input for SOLAR
> COLLECTOR
> > PARAMETERS:FLAT PLATE
> > >
> > >
> > > Hella all,
> > >
> > > I am interested in simulating the performance of solar panels
> > > distributed by a German manufacturer (Vitosol).
> > >
> > > I do have catalog data from the distributer. The catalog
> > stipulates
> > > that..
> > >
> ___________________________________________________________________
> > >
> > > "The thermal loss coefficient and optical efficiency combine
to
> > form
> > > the collector efficiency curve which can be calculated on the
> > basis
> > > of the following formula:
> > >
> > > n = n0 - k1 . (dt/Eg) - k2 . (dt^2/Eg)."
> > >
> > >
> >
>
_____________________________________________________________________
> > >
> > > However, E+'s idf requires:
> > >
> > > (a) Test Fluid
> > > (b) Test Volumetric Flow Rate {m3/s}
> > > (c) Test Correlation Type
> > > (d) Coefficient 1 of Efficiency Equation (Y-Intercept)
> > > {dimensionless}
> > > (e) Coefficient 2 of Efficiency Equation (1st Order) {W/m2-K}
> > > (f) Coefficient 3 of Efficiency Equation (2nd Order) {W/m2-K2}
> > > (g) Coefficient 2 of Incident Angle Modifier (1st Order)
> > > (h) Coefficient 3 of Incident Angle Modifier (2nd Order)
> > >
> > > As a result, I am unsure of the values I should instantiate in
> my
> > > input file. I would appear to have direct input for (d) only
as
> > the
> > > solar circuits have a mixture of glycol in order to provide
> frost
> > > protection.
> > >
> > > Does anyone have advice from previous experiences?
> > >
> > > Kind regards
> > >
> > > -Elmer
> > >
> > >
> > >
> > >
> > >
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