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[EnergyPlus_Support] Re: GSHP Parameter coefficient generator
Richard
I greatly appreciate the information that you provided. But in all honesty you have completely lost me.
First, in the 'rated' values of the CoeffCalculator the manual says to uses based on max Q. Is this Qmax that the heat pump could produce? or the Qmax of the design case condition I am modeling?
Secondly, where does the part load ratio relate to all this? I do not see it as a variable in the IDF file? so therefor I am unclear how to make use of the spreadsheet you uploaded and the purpose of it.
Please forgive my ignorance
-
aj
--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, Richard Raustad <RRaustad@...> wrote:
>
> I should have included the "ratio" variables. You need to know this when
> creating the coefficients. I was actually just doing this today for a
> simulation. I'll upload the spreadsheet so you can have a look.
>
> I am not including the air and water flow rate variations since I will
> be operating the HP at the design flow rates. And I have only done
> cooling so far (too many other things to do today).
>
> http://tech.groups.yahoo.com/group/EnergyPlus_Support/files/Examples/SimpleModel_Coefficients.xls
>
> Tref = 273.15
> ratioTDB = ((LoadSideInletDBTemp+Tref)/Tref)
> ratioTWB = ((LoadSideInletWBTemp+Tref)/Tref)
> ratioTS = ((SourceSideInletTemp+Tref)/Tref)
> ratioVL =
> (LoadSideMassFlowRate/(AirVolFlowRateRated*PsyRhoAirFnPbTdbW(StdBaroPress,LoadSideInletDBTemp,LoadSideInletHumRat)))
> ratioVS =
> (SourceSideMassFlowRate/(WaterVolFlowRateRated*RhoH2O(SourceSideInletTemp)))
>
> Richard Raustad wrote:
> >
> >
> > Use only the full load data set, the part-load performance is calculated
> > inside the model based on the part-load ratio (PLR) required to meet the
> > load
> >
> > QLoadTotal = TotalCapRated*(TotalCapCoeff1 + (ratioTWB * TotalCapCoeff2)
> > + (ratioTS * TotalCapCoeff3) + &
> > (ratioVL * TotalCapCoeff4) + (ratioVS * TotalCapCoeff5))
> >
> > QSensible = SensCapRated*(SensCapCoeff1 + (ratioTDB * SensCapCoeff2) +
> > (ratioTWB * SensCapCoeff3) + &
> > (ratioTS * SensCapCoeff4) + (ratioVL * SensCapCoeff5) +
> > (ratioVS * SensCapCoeff6))
> >
> > !scale heat transfer rates
> > QLoadTotal = QLoadTotal*PartLoadRatio
> > QSensible = QSensible*PartLoadRatio
> >
> > Alan Jackson wrote:
> > >
> > >
> > > I am glad you mentioned the curve fit model because this is really the
> > > origin of my original question. The problem I have is that if I input
> > > a series of full load condition into the spreadsheet i can get error %
> > > less than 5 in both heating and cooling, but as soon as I include the
> > > part load values the error % ends up between 30-40%.
> > >
> > > -
> > > aj
> > >
> > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > > <mailto:EnergyPlus_Support%40yahoogroups.com>, Edwin Lee
> > > <leeed2001@> wrote:
> > > >
> > > > Alan,
> > > >
> > > > It looks like R410 is not available in the spreadsheets, if you
> > > enter R410a,
> > > > the code should issue a warning such as "Refrigerant not in list".
> > > You may
> > > > want to try using the simpler curve fit routine before going to the
> > > > parameter estimation to see how well the curve fit works. In heating
> > > mode,
> > > > with a large data set (~1000 points), I have curve fits that match
> > > to within
> > > > 3-4% of the manufacturer's data points. In cooling mode, the sensible
> > > > capacity does not typically match as well, but it may be within 10%.
> > > Using
> > > > the curve fit would alleviate the problem with the refrigerant being
> > > > unavailable, and there are also known issues with the parameter
> > > estimation
> > > > model. (For instance, if you attempt to autosize the capacity in E+
> > > after
> > > > you generate the parameters, the parameters and new capacity may be in
> > > > conflict, and could cause errors. Whereas the curve fit model scales
> > > nicely
> > > > with capacity, and has not shown any problems.)
> > > > Just my thoughts,
> > > > Edwin
> > > >
> > > > On Thu, Jun 4, 2009 at 8:46 AM, Alan Jackson <alanjackson7@> wrote:
> > > >
> > > > >
> > > > >
> > > > > Edwin
> > > > >
> > > > > Thank you for your response. I have expanded my dataset and I
> > > believe I
> > > > > have enough information for a good curve fit. I am looking a the
> > > > > ParamEstimator Tab and do not see R410a listed as a refrigerant.
> > > > >
> > > > > Is this an acceptable refrigerant for these calculations?
> > > > >
> > > > > -
> > > > > aj
> > > > >
> > > > >
> > > > > --- In EnergyPlus_Support@xxxxxxxxxxxxxxx
> > <mailto:EnergyPlus_Support%40yahoogroups.com>
> > >
> > <mailto:EnergyPlus_Support%40yahoogroups.com><EnergyPlus_Support%40yahoogroups.com>,
> > > > > Edwin Lee <leeed2001@> wrote:
> > > > > >
> > > > > > I think the basic answer is that you want the data to cover the
> > > spectrum
> > > > > of
> > > > > > operation for that component during the simulation. The curve
> > > fit will
> > > > > fit
> > > > > > best within the data provided. Extrapolation from that data may
> > > result in
> > > > > > inaccuracies.
> > > > > > The input to the utility requires that each input must vary. If a
> > > > > constant
> > > > > > is given for entering air temperature throughout your data points,
> > > > > without
> > > > > > any variation, a curve fit won't really make sense, and the
> > > spreadsheet
> > > > > tool
> > > > > > may give non-sensible answers.
> > > > > > A more advanced tool is currently under development which will
> > > allow the
> > > > > > user to easily enter the tabulated data as found in a heat
> > pump data
> > > > > sheet
> > > > > > along with the correction factors which are also found. This is
> > > used to
> > > > > > develop a large dataset which will then result in a good quality
> > > curve
> > > > > fit.
> > > > > > For the spreadsheet the user must apply these manually.
> > > > > >
> > > > > > Edwin
> > > > > >
> > > > > > On Wed, Jun 3, 2009 at 4:57 PM, Alan Jackson <alanjackson7@>
> > wrote:
> > > > > >
> > > > > > >
> > > > > > >
> > > > > > > This is my first go around at modeling a GSHP in Energyplus
> > > and I am
> > > > > going
> > > > > > > through the documentation for the parameter-coefficient
> > generator
> > > > > > > spreadsheet and needed some feedback. I have all the
> > manufacturer
> > > > > > > information as far as performance values. My question relates
> > > to the
> > > > > amount
> > > > > > > of data required.
> > > > > > >
> > > > > > > The user manual states "The data points must have varying inlet
> > > > > conditions
> > > > > > > (e.g. water flow rates, inlet water temperatures, etc.) that
> > > covers the
> > > > > > > entire range of the heat pump operating conditions."
> > > > > > >
> > > > > > > When they say "covers the entire range" doe s this mean we
> > > would need
> > > > > to
> > > > > > > enter both part load and full load conditions? or is it
> > > possible to get
> > > > > > > useful outputs with varying temperatures at full load ratings?
> > > > > > >
> > > > > > > I think I already know the answer to this but looking for some
> > > > > > > confirmation.
> > > > > > >
> > > > > > > Thanks
> > > > > > >
> > > > > > > -
> > > > > > > aj
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > >
> > >
> >
> > --
> > 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 <http://www.fsec.ucf.edu>
> >
> > UCF - From Promise to Prominence: Celebrating 40 Years
> >
> >
>
> --
> 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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