PURPOSE: To reduce an occupied volume and to reduce the cost by a method wherein a cooling water pipe and a cold pipe are connected at each refrigerator to the tube plate on the one side of two heat exchangers arranged in juxtaposition, and a bypass pipe is connected between the two heat exchangers so that cooling water and cold water passing the one heat exchanger are caused to flow through the other heat exchanger.

CONSTITUTION: In turbo type refrigerators 1-1 and 1-2, a compressor 4, drive machines 2 and 3, and gas-liquid separators 7-1 and 7-2, in which vaporizers 6-1 and 6-2 and condensers 5-1 and 5-2 are positioned in juxtaposition in shells 6A and 5A through pressure reducing means 17-1 and 17-2, are arranged on the shell of heat-exchangers 11-1 and 11-2, and the two turbo type refrigerators 1-1 and 1-2 are arranged in an opposite direction to each other. A header part 12-1 is located on the heat exchanger 11-1 side of the one tube plate 10A and a header part 12-1 on the heat exchanger 11-2 side. Cooling water pipes 13-1 and 14-1 are connected to the header part 12-1 and cooling water pips 13-2 and 14-2 to the header part 12-2, and the direction of the flows of cold water and cooling water are extended in an opposite direction to each other. A bypass piping 16 is cooling water pipe for intercoupling the condenser 5-1 side of the heat exchanger 11-1 and the condenser 5-2 side of the heat exchanger 11-2.