To prevent the re-discharging of collected ice particles by structuring an ice particle capturing for capturing in particles inside a water flow path with a filter woven of a large number of wire rods with a predetermined spacing and angle, and kept at the temperature of the freezing point of water.

In an air conditioning unit, which runs an ice-making operation using midnight power and a cooling operation utilizing the stored cold at daytime, the water in a thermal storage tank is circulated through a water circulating circuit driven by a pump at the ice making operation. In this case, the water is gated by a refrigerant in a refrigerant circuit at a pre-heater and sent passing through the ice particle cap capturing unit 20 to a mixer to be agitated. The ice particle capturing unit 20 is comprised of many wire rods 22 wired for forming a lattice as a filter and held at the temperature of the freezing point of water. Therefore. the ice particles are collected by the ice I around the wire rods 22, and the captured ice particles are melted from the surround and being gradually reduced an extinguished.