CHILLING UNIT AND AIR CONDITIONING SYSTEM

A chilling unit includes an upstream system circuit including a first refrigerant circuit and a second refrigerant circuit, a downstream system circuit including a third refrigerant circuit and a fourth refrigerant circuit, a heat medium circuit including a first branch circuit and a second branch circuit, an outlet temperature detecting unit disposed downstream of a third refrigerant-to-heat medium heat exchanger and a fourth refrigerant-to-heat medium heat exchanger in the heat medium circuit and configured to measure a temperature of a heat medium, and a controller configured to control operation of the first compressor, the second compressor, the third compressor, and the fourth compressor. The controller includes a determining unit configured to determine whether the temperature of the heat medium measured by the outlet temperature detecting unit is at or below a temperature threshold and an increasing unit configured to, when the determining unit determines that the temperature of the heat medium is at or below the temperature threshold, increase an operating frequency of the first compressor, the second compressor, the third compressor, or the fourth compressor.