Abstract: The disclosure relates to a fully integrated single stage centrifugal air compression system that exhibits a relatively high flow rate at relatively low pressure. The air compression system comprises a single impeller that is driven through a belt drive by a conventional electric motor. A novel parallel wall axially split diffuser converts the high kinetic energy of air leaving the impeller into pressure energy. Cooling of the air compressor is achieved by an integral fan on the motor pulley which draws filtered ambient air into a plenum. Plenum air is ducted through a novel system of heat exchangers which draw heat from the compressor bearings. A passage through the center of the compressor drive shaft conducts pressurized air from the plenum through the drive shaft to cool the bearings, resulting in a bearing running temperature slightly above ambient.