I have a CURVE-FIT question (yes, the same darn project). I am creating
curve data for some Daikin VRV using the raw data. The capacity curves are
no problem. The governing equation for cooling is:
CAPt=Cooling-Capacity*COOL-CAP-FT (EWB,ODB). I have really good data tables
that provide the capacity at about 6 entering web bulb temperatures and 20
outdoor dry bulb temperatures so I'm good to go there,. All the capacities
have been normalized to the ARI conditions and the curves entered as
BI-QUADRATIC-T. The problem I'm having is with the cooling EIR curves. The
governing equation here is
EIRt=COOLING-EIR*COOL-EIR-FT*(EWB,ODB)*COOL-EIR-FPLR (PLR). There is no
handy example to refer to like there is for the capacity curves. At first I
just proceeded as I did with the capacity curve data: called it a
BI-QUADRATIC-T and normalized the EIRs as a function of the entering wet
bulb and outdoor dry bulb to the ARI EIR. But what about the PLR? Isn't it a
third independent variable? Has anyone had experience with this and if so
please enlighten me as to what equation type did you use and how did you
include the PLR.

--
Carol Gardner PE