Abstract: A cooler includes an estimator. The estimator is configured to estimate a coolant temperature from a measurement value of the temperature sensor. The estimator is configured to determine a difference by subtracting an immediately preceding measurement value from a current measurement value, determine a correction value from the difference, and output an estimated value of the coolant temperature. The estimated value is obtained by adding the correction value to the current measurement value. The correction value is obtained by multiplying a gain by the difference. The gain is determined from a time constant, the gain is determined according to a flow rate of the coolant. The time constant is obtained when a transfer function of heat transferred from the coolant to the temperature sensor is modeled as a first order lag system.

Abstract: Cooling apparatuses and a system including the same may be provided. The cooling apparatus including a freezer, a first cooling unit configured to cool a first cooling water supplied to the freezer in open air, and a second cooling unit configured to cool a second cooling water supplied to the first cooling unit may be provided. According to a temperature difference between the open air and the first cooling water, the second cooling unit may circulate the second cooling water separately with respect to the first cooling water or mix the second cooling water into the first cooling water.

Abstract: A harmonic component extraction unit obtains a command value of compensating current from a harmonic component of the load current. A difference current generation unit obtains a deviation between the compensating current and a value obtained by leading a phase of the command value by a predetermined phase difference. A current controller generates a control signal based on output of the difference current generation unit. A driving signal generation circuit generates, based on the control signal, a driving signal driving a parallel active filter.

Abstract: A first heat exchanger, a desiccant block, and a second heat exchanger are arranged in series. In a dehumidification operation, a first operation mode in which the first heat exchanger acts as a condenser or a radiator and the second heat exchanger acts as an evaporator and a second operation mode in which the first heat exchanger acts as an evaporator and the second heat exchanger acts as a condenser or a radiator are alternately repeated.