To provide a refrigeration unit and a method for operating the same for reducing the power consumption as a total shop by effectively utilizing the cold heat accumulated in a heat accumulation tank, and utilizing the cold heat according to the cooling load, the heat accumulation, etc.

The refrigeration unit comprises a first refrigerant circulation passage 15 having a first compressor 11, a first outdoor heat exchanger 12, a first cooling throttling device 13, and a first heat exchanger 14 for cooling works, a first refrigeration unit 10 having a heat accumulation passage 18 with a first throttling device 16 for heat accumulation and a first heat exchanger 17 for heat accumulation, a second refrigerant circulation passage 36 having a second compressor 31, a second outdoor heat exchanger 32, a second heat exchanger 33 for heat reception, a second cooling throttling device 34, and a second heat exchanger 35 for cooling works, a second refrigeration unit 30 of low cooling temperature having a bypass passage 37 to bypass the second outdoor heat exchanger, and a heat accumulation tank 42 storing heat accumulation materials 41 which receives the cold heat from the first refrigerant by the first heat exchanger for heat accumulation and gives the cold heat to the second refrigerant by the second heat exchanger for heat reception.