Abstract: A refrigeration system includes a compressor, a motor, variable pitch pulleys mounted on the ends of the compressor and motor shafts, and an endless belt looped around the motor and compressor pulleys for drivingly connecting the motor to the compressor. A sensor determines a variance in a refrigerant characteristic of the system from a predetermined value. An electrically powered actuator is responsive to the sensor and effects axial movement to one pulley component of the motor for thereby changing the pitch diameter of the motor pulley and to in turn vary the pitch diameter of the pulley on the compressor so as to change the speed of rotation of the compressor.

Abstract: An air conditioning system for a grocery store having refrigerated food displays along certain aisles of the store includes a plurality of air ceiling mounted air outlet diffuser units. A plurality of the units are positioned substantially above the aisles adjacent the refrigerated food displays. Each diffuser unit positioned above the aisle adjacent the refrigerated food displays is constructed so as to provide a downward flow of conditioned air into the store in a manner so that shoppers receive conditioned air free of drafts while heavy, cool, stagnant air lying adjacent the refrigerated food displays is induced upwardly into upper regions of the store. Each diffuser unit has a housing with a flared exit mouth, a tubular air passageway within the housing and an annular air passageway therebetween. A plurality of vanes are positioned in the annular passageway for producing rotational, highly turbulent currents of air flowing from the passageway.

Abstract: An air conditioning system for a grocery store having refrigerated food displays along certain aisles of the store includes a plurality of ceiling mounted air outlet diffuser units. A plurality of the units are positioned substantially above the aisles adjacent the refrigerated food displays. Each diffuser unit is positioned above the aisle adjacent the refrigerated food displays and is constructed so as to provide a downward flow of conditioned air into the store and over an extended area of the aisle in a manner so that shoppers receive conditioned air free of drafts while heavy, cool, stagnant air lying adjacent the refrigerated food displays is induced upwardly into upper regions of the store. Each diffuser unit has a housing with a flared air exit mouth which includes an outwardly extending arcuate surface to define a rounded outlet mouth thereat so that some horizontal discharge of air always is provided. A tubular air passageway within the housing includes an annular air passageway therebetween.