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Re: [EnergyPlus_Support] Calculating Water-to-Air Heat Pump Curve-fitting Coefficients
Sorry about the slow response on this question.
I will answer your last question first. Yes, the curve fits in the example
file should be fairly generic and you should expect a reasonable result by
changing only the nominal values for capacity, flow rate, and rated COP.
If your study requires more specific modeling of a particular piece of
equipment, then be sure to consult the Input Output Reference and/or the
Engineering Reference to find the equations used in the particular equipment
model. The equations will show what the x and y variables are, and how the
various curves are multiplied together to obtain a final capacity or energy
consumption result. Curves are generally normalized, so that the result of the
curve is 1.0 at nominal or rated conditions.
There is an example Excel spreadsheet in the files area of the yahoo group
which shows how to do a bi-quadratic curve-fit using the Excel LINEST function.
(see http://tech.groups.yahoo.com/group/EnergyPlus_Support/files/Examples/ )
I do not know where to obtain the spreadsheet that is cited in the Tang paper.
Mike
On 5 Mar 2007 at 3:55, energyplus99 wrote:
> I'm trying to generate curve-fitting coefficients for:
>
> COIL:WATERTOAIRHP:EquationFit:COOLING and
> COIL:WATERTOAIRHP:EquationFit:HEATING
>
> objects. The EP InputOutputReference alludes to using a generalized
> least-squares method and Tang, in Appendix B of his paper (Modeling
> Packaged Heat Pumps In a Quasi-steady State Energy Simulation Program)
> references an Excel spreadsheet for calculating these. But there are
> no specifics on exactly how to do this.
>
> Does anyone know how I can get a copy of this spreadsheet or how I can
> generate these coefficients using the current version of EnergyPlus?
> Is it possible that the coefficients published in the EP examples (for
> example, HeatPumpWaterToAirEquationFit.idf) are universal enough to be
> applicable to a wide variety of heat pump brands (with possibly only
> adjustments to rated flowrates, capacities and power consumption
> necessary)? Any thoughts would be much appreciated!
>
>
>
> The primary EnergyPlus web site is found at:
> http://www.energyplus.gov
>
> The group web site is:
> http://groups.yahoo.com/group/EnergyPlus_Support/
>
> Attachments are not allowed -- please post any files to the appropriate folder
> in the Files area of the Support Web Site.
>
> EnergyPlus Documentation is searchable. Open EPlusMainMenu.idf and press the
> "search" button.
>
> Yahoo! Groups Links
>
>
>
>
>
========================================================
Michael J. Witte, GARD Analytics, Inc.
EnergyPlus Testing and Support
EnergyPlus-Support@xxxxxxxx
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