Abstract: A refrigeration system (10) having a compressor rotor (20) rotatably supported by a plurality of hydrodynamic bearings (22 and 24) lubricated by oiless pressurized liquid refrigerant and pressurizing refrigerant which flows to a condenser (34) providing liquid refrigerant which flows to an evaporator (68) in fluid communication with the condenser and the compressor in accordance with the invention includes a refrigeration circuit (36) coupled to the compressor, for providing pressurized refrigerant to the hydrodynamic bearings from the compressor and to the evaporator; a bearing pump (26), coupled to the refrigerant circuit and to the condenser, for providing pressurized refrigerant to the refrigeration circuit; a first temperature sensor (101) sensing a temperature Tsink of a heat exchange fluid at the condenser and providing a temperature signal representative of the temperature Tsink of the heat exchange fluid at the condenser; a second heat exchange sensor (103) sensing a temperature Tsource of a heat exc