[EnergyPlus_Support] Performance curves conversion from DOE2 to EnergyPlus on Multi stage DX cooling

["fang_xia" <fang_xia@xxxxxxxxx>]

Hi, I did a little study to see how I can convert DOE2 equipment 
curve fit for a multi stage DX cooling performance curve to 
EnergyPlus. Besides the unit conversion and performance at different 
speed ratio parts, there are three following items that I am asking 
for expert help on:

1. Part load ratio (PLR): DOE2 specifies both cooling capacity and 
EIR as a function of PLRs. In E+, however, functions of CoolCap and 
EIR do not have this option available. Instead, it calculates both 
CoolCap and EIR at full load operating conditions, and let both 
change linearly as PLR steps down from 100% down to 0%. 

2. Flow Fraction (FF): both CoolCap and EIR vary as a function of 
FF. But this function seems completely ignored by DOE2. I myself 
have a bit trouble interpreting this function. For single speed DX, 
FF appears to be 1 always when fan cycles together with compressor, 
though the example file does not appear so. For multi speed DX 
cooling, it seems I need to give consideration on fan speed linear 
varation with respect to compressor speed. But regardless, to 
convert from DOE2 to EnergyPlus seems a missing link. 

3.DOE2 documentation does not appear to have cycling losses included 
in the equation for calculating compressor power. Even though, the 
quadratic equation is by default in DOE2. In E+, PLF(PLR) is the 
equation to take care of that. From speed 0 to 1, the cyling PLF
(PLR) is there, but not from speed 1 to n.

Your answer is greatly appreciated.

Thank you.

Xia




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