ROOT ICE DETECTOR, ROOT ICE DETECTING PROGRAM AND ROOT ICE DETECTING METHOD FOR UNIT COOLER, AND REFRIGERATION SYSTEM EQUIPPED WITH ROOT ICE DETECTOR

摘要

PROBLEM TO BE SOLVED: To detect the formation of root ice in a unit cooler in an early stage.;SOLUTION: Whether the unit cooler has started defrosting operation is determined (S1). If the unit cooler has started defrosting operation, a time t₁ when the detected temperature T_m of a temperature sensor installed at the unit cooler is within a temperature range from T_L to T_U during defrosting operation, and a time t₂ from the time of the detected temperature T_m reaching the temperature T_L until the end of defrosting operation, are measured (S2-S8). Whether the ratio of the time t₁ to the time t₂ is a reference value or more is determined (S9). The formation of root ice is determined if the ratio is the reference value or more, and the result is output (S10). No root ice is determined if the ratio is less than the reference value, and the result is output (S11).;COPYRIGHT: (C)2008,JPO&INPIT