Patent ID: 7287395

Claim:
A commercial refrigeration system comprising: a first refrigeration unit at a retailer and in communication with a first refrigeration case disposed within a retail space, said first refrigeration unit including a first variable capacity compressor operable between a full capacity mode and a reduced capacity mode and a first fixed capacity compressor operable between a full capacity mode and a zero capacity mode, said first variable capacity compressor and said first fixed capacity compressor being fluidly coupled to a first suction manifold and fluidly coupled to a first discharge manifold, said first suction manifold and said first discharge manifold coupled to a first refrigeration circuit operating within a first temperature range; a first controller associated with said first refrigeration unit to stage said first variable capacity compressor and said first fixed capacity compressor based on a comparison of a first operating condition of said first refrigeration unit to a first refrigeration circuit set point; a second refrigeration unit at the retailer and in communication with a second refrigeration case disposed within the retail space, said second refrigeration unit including a second variable capacity compressor operable between a full capacity mode and a reduced capacity mode and a second fixed capacity compressor operable between a full capacity mode and a zero capacity mode, said first variable capacity compressor and said first fixed capacity compressor being fluidly coupled to a second suction manifold and fluidly coupled to a second discharge manifold, said second suction manifold and said second discharge manifold coupled to a second refrigeration circuit separate from said first refrigeration circuit and operating within a second temperature range different than said first temperature range; and a second controller associated with said second refrigeration unit to stage said second variable capacity compressor and said second fixed capacity compressor based on a comparison of a second operating condition of said second refrigeration unit to a second refrigeration circuit set point.