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[EnergyPlus_Support] Re: EIR Chiller Performance Curve Fitting



Dear sam

      I check your excel file. I have some question about your 
calculation:
  1. You used (Qr/Qa) as PLR and (Pa/Pr) as EIR output ratio for the 
third.I get confused about these settings. Could you please tell me 
why you choose these parameters? P.S. Pa,Pr,Qa,Qr are power 
available, power rated, capacity available and capacity rated.
  2. And I look into the curve fitting results in sheet1 of your 
file. Is it related to our discussion?  I can not understand the 
purpose of this sheet. Please explain it for me.

       Thank you in advance
                                                    charlie

--- In EnergyPlus_Support@xxxxxxxxxxxxxxx, wing sun lee 
<samwslee@y...> wrote:
> Hi,
>  
> Please go here 
http://groups.yahoo.com/group/EnergyPlus_Support/Files/Problem_Submit
tals/Input Problem/Fit curve biquadratic d.xls 
> 
> It seems to be corrected and solved
> 
> SAMLEE
> 
> 
> donbshireyiii <shirey@f...> ¼¶¼g:
> Charlie and SAMLEE,
> 
> In the spreadsheet you are using, it looks like EIR as a function
> of PLR is not being properly calculated.
> 
> The spreadsheet seems to be using available capacity at the current
> operating conditions divided by the design (rated) capacity of the
> chiller.  This is not correct.... is should be just as the
> input/output reference says... PLR = (cooling load) divided by
> (available capacity at the current operating conditions).
> 
> Don 
> 
> --- In EnergyPlus_Support@xxxxxxxxxxxxxxx, wing sun lee
> <samwslee@y...> wrote:
> > Hi Charlie,
> >  
> > I just use your advice that the PRL shoudl equal to the ratio of
> cooling load to the available capacity. 
> > Please see my attached file at
> http://groups.yahoo.com/group/EnergyPlus_Support/F
> iles/Problem_Submittals/Input
> Problem/Fit curve biquadratic b.xls 
> >  
> > SAMLEE
> > 
> > energypluser <energypluser@y...> ¼¶¼g:
> > Dear Mike,
> > 
> >      I wanna simulate a electric chiller with the EIR module. 
And I 
> > found that you give a EXCEL example for the curve fitting. But I
> think 
> > the third curve in your example file may not be correct. 
> >      According to the input/output reference, the third curve is
> the 
> > EIR output ratio in function of Part Load Ratio. The PLR
> calculation in 
> > your file is the ratio of the available capacity to the nominal 
> > capacity.  In my opinion, PLR should equal to the ratio of the
> cooling 
> > load to the available capacity. Am I right?
> >       If I am right, could you please tell me how to obtain the
> third 
> > curve for my simulation based on the manufacturer catalog.
> >       Thank you in adavance
> > 
> >                                                             
charlie 
> 
> 
> 
> 
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