Formula & worked example
IPLV=0.01A+0.42B+0.45C+0.12D for kW/ton inputs at 100/75/50/25% load.
For 0.65, 0.55, 0.50 and 0.58 kW/ton, the weighted value is about 0.532 kW/ton.
Plant engineering calculator · Updated Sep 17, 2026
Chiller IPLV / NPLV Calculator — Weighted Part-Load Efficiency
Calculate a transparent weighted part-load chiller efficiency from 100%, 75%, 50% and 25% load-point kW/ton values using AHRI-style IPLV weighting, with equivalent COP and annualized comparison outputs.
Inputs
Live result
Weighted IPLV/NPLV 0.5321 kW/ton
Equivalent COP 6.609383
Equivalent EER 22.55215 Btu/Wh
Annualized energy at entered equivalent hours 798.15 MWh
Annualized cost 95,778
Assumptions & limits
- The four-point weighting is a rating-style comparison, not a site-specific annual energy model.
- NPLV uses the same weighting concept at non-standard conditions; verify rating conditions and manufacturer data.
Frequently asked questions
What does this Chiller IPLV / NPLV Calculator calculate?
Calculate a transparent weighted part-load chiller efficiency from 100%, 75%, 50% and 25% load-point kW/ton values using AHRI-style IPLV weighting, with equivalent COP and annualized comparison outputs.
Can I use the result for final equipment selection?
Use it for screening, benchmarking and option comparison. Final selection should use measured conditions, manufacturer performance data and applicable engineering standards.
Why are assumptions shown beside the calculation?
Plant calculations change materially with pressure basis, reference conditions, efficiencies and operating profile. Explicit assumptions make the result auditable instead of hiding those choices.