pg 9 shows the performance at 5 evaporator leaving water temperatures and 4 condenser leaving water temperatures. This should be sufficient for modeling, as long as the "simulated" temperatures stay within or near those temperatures.
You will want to set up a spreadsheet with the fundamental equation, if you use the Chiller:Electric:ReformulatedEIR object, then the fundamental equation for Cooling Capacity as a Function of Temperaure is:
CAPFT = a + b*CWS + c*CWS**2 + d*LCT + e*LCT**2 + f*CWS*LCT
CWS = supply (leaving) chilled water temperature(C)
LCT = leaving condenser fluid temperature(C)
CAPFT = normalized capacity (operating capacity divided by rated capacity)
In the spreadsheet, take the data from the manufacturers catalog and set up 6 columns of data:
CAPFT, CWS, CWS*CWS, LCT, LCT*LCT, and CWS*LCT.
Yes, you actually multiply out the equation inputs. For example, a 5 C CWS and 30 C LCT yields a row in the spreadsheet like this: I didn't calculate the CAPFT value so I will use X. You should have 20 rows. The X in this example should be near 1, and you should only see one "1" when you are done at the rated conditions. All other values of X should only be close to 1, unless it's a coincidence in the data.
X, 5, 25, 30, 900, 150
Once you do this for all available data, perform a regression on the data set to calculate the coefficients a-f.
The part-load ratio curve will be harder and I suggest you use a generic curve from the example files.
See also the example spreadsheet in the Files/Examples folder called Excel Biqudratic Fit.zip
On 11/29/2011 11:07 AM, Ignacio wrote:
Hello,
I wanto to model a water cooled chiller and an air cooled chiller.
But I think I don't have enough info about how the chiller works.
I will use two Carrier machines because I found some information about them,my Nominal capacity is round 80kW:
-Air Cooled Chiller: http://eto.carrier.com/litterature/psd/13430_PSD_03_2009_30RW_LR.pdf
-Water Cooled Chiller: http://eto.carrier.com/litterature/psd/13461_PSD_12_2009_30RBS_30RQS_LR.pdf
How can I get the coefficients for the "Capacity ratio curve","Power ratio curve" and "Full load ratio curve"?
Thanks in advance,
Ignacio Gomis
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