# Chiller IPLV Calculation

I want to adjust IPLV of `Chiller:Electric:EIR`

. I referred to Engineering Reference and calculate the IPLV in Excel before running simulation, which can avoid iterating simulation many times. When I change the coefficients of three chiller performance curves in the Excel, I can get the IPLV instantly.

However, **the calculated IPLV (6.62) in the Excel is approximately 1.5% larger than the reported IPLV (6.52) in the html file**. I did a sizing run to output the html file.

I saw this post, and I have already fixed the `Minimum Value of y`

. IPLV calculating conditions are within the Minimum/Maximum value of x/y. (When `Chiller:Electric:EIR`

is generated from HVACTemplate, the default `Minimum Value of y`

for `Curve:Biquadratic`

is 24 which is higher than the entering condenser water temperature of 18.3degC at 25% load, which should be fixed.)

`Minimum Unloading Ratio`

of `Chiller:Electric:EIR`

is set to 0.1 which is lower than 0.25, so I think the degradation coeﬀicient does not affect the IPLV calculation.

What is causing this difference? I can't identify it. Is it due to the significant figures? Or are the numbers in Engineering Reference different from numbers actually used in EnergyPlus?

The excel, html file and the idf file (V9-6-0) are **here**. I want to calculate IPLV accurately in Excel to avoid running simulation again and again. Any suggestions would be appreciated.