This series of efficient inverter screw Water chillers are large commercial air conditioners that can be widely applied to air conditioning schemes in new and reconstructed small or large buildings for commercial and industrial use, for example, in hotels, restaurants, apartments, office buildings, hospitals, and factories. Each unit features standard components such as efficient, low-noise semi-hermetic screw compressors, shell-and-tube condensers, flooded evaporators, and microcomputer control centers.