OIL-FREE LIQUID CHILLER

摘要

A refrigeration chiller (10) employs a centrifugal compressor (12) the impellers (42, 44) of which are mounted on a shaft (48) which it itself mounted for rotation using rolling element (53) bearings (52) lubricated only by the refrigerant which constitutes the working fluid of the chiller system (10). Apparatus is taught for providing liquid refrigerant to (1.) the bearings (25) immediately upon chiller start-up, during chiller operation and during a coastdown period subsequent to shutdown of the chiller (10) and (2.) the drive motor (40) of the chiller's compressor (12) for motor cooling purposes. By use of a variable speed-driven motor (40) to drive the compressor (12), optimized part load chiller performance is achieved in a chiller which does not require or employ an oil-based lubrification system.