AHRI statistics show that actual operating loads of central air conditioners are mainly between 40%-70%.

The DC inverter technology of oil-free chillers results in highly energy efficient part loads.

Energy-saving Formula: RPM 3 ∝ Motor Power Consumption

When an oil-free chiller runs at part loads, its capacity control range can be adjusted from 5% to 100% via variable frequency control (30-800hz) of the oil-free compressor motor. Since compressor power consumption is proportional to compressor RPM3, when cooling load of the chiller and motor RPM declines, motor kW will dramatically drop accordingly and IPLV can be up to 11.2. Traditional chillers on the other hand adjust capacity via suction/discharge bypass or IGV. There is no obvious change in power consumption of motor. COP is about 6 and IPLV about 7. In conclusion, oil-free chillers offer higher energy efficiency at part loads when comparing to traditional chillers.

MULTISTACK, the Inventor of Modular Chillers and Oil-free Chillers www.multistack.com.cn