Abstract: By supplying a refrigerant utilized for cooling brine at a brine chiller unit (4) to a cooler (21) of a blast chiller (2), the internal space at the blast chiller (2) is cooled. In addition, the brine cooled at the brine chiller unit (4) is supplied to an ice heat storage tank (23) during the night and is supplied to a cold trap (7) during the daytime by switching a three way reversing valve (17). Thus, ice-making and chilled water storage are achieved at the ice heat storage tank (23) during the nighttime so that a tumble chiller (3) performs cooling during the daytime by using the chilled water that has been stored at the ice heat storage tank (23). Consequently, during the daytime, three coolers, i.e., the vacuum cooler (1), the blast chiller (2) and the tumble chiller (3), can be operated with a single brine chiller unit (4).