Patent ID: 7617695

Claim:
A refrigeration system for cooling a space using a refrigerant, the refrigeration system comprising: a refrigeration circuit including a plurality of variable capacity compressors arranged in parallel, the plurality of variable capacity compressors operable to compress the refrigerant, wherein one of the plurality of variable capacity compressors is a first variable capacity compressor started to define a first compressor in a queue of running compressors, and wherein another of the plurality of variable capacity compressors is a second variable capacity compressor started after the first compressor in the queue to define a last compressor in the queue, a condenser in fluid communication with the plurality of variable capacity compressors, the condenser operable to receive compressed refrigerant from the plurality of variable capacity compressors and to condense the refrigerant, and at least one evaporator in fluid communication between the condenser and the plurality of variable capacity compressors, the at least one evaporator operable to receive condensed refrigerant from the condenser, to evaporate the refrigerant to refrigerate the space within a predetermined temperature range, and deliver the evaporated refrigerant to the plurality of variable capacity compressors, wherein the at least one evaporator defines a load while operating to refrigerate the space within the predetermined temperature range; and a controller programmed to control the operation of the plurality of variable capacity compressors to match the capacity of the plurality of variable capacity compressors to the load when the first compressor and the last compressor are each running below maximum capacity and above minimum capacity by increasing the capacity of the last compressor in the queue and not increasing the capacity of the first compressor in the queue when the capacity of the plurality of variable capacity compressors is lower than the load and by decreasing the capacity of the first compressor in the queue and not decreasing the capacity of the last compressor in the queue when the capacity of the plurality of variable capacity compressors is higher than the load.