Abstract: An air conditioner includes a refrigerant circuit, sensors that measure an amount representing a state of refrigerant in the refrigerant circuit, and a controller. The controller executes normal operation according to air conditioning load and a first detection operation of detecting refrigerant leakage. The controller adjusts a degree of subcooling at an outlet of the condenser to a first value during normal operation. The controller detects a value related to discharge temperature of the compressor or a value related to degree of superheating at an outlet of the evaporator, based on a sensor measurement result. The controller adjusts degree of subcooling to a second value larger than the first value when executing the first detection operation, and determines that refrigerant is leaking when the value related to discharge temperature of the compressor or the value related to degree of superheating is equal to or larger than a threshold value.

Abstract: An air conditioner includes a refrigerant circuit, sensors that measure an amount representing a state of refrigerant in the refrigerant circuit, and a controller. The controller executes normal operation according to air conditioning load and a first detection operation of detecting refrigerant leakage. The controller adjusts a degree of subcooling at an outlet of the condenser to a first value during normal operation. The controller detects a value related to discharge temperature of the compressor or a value related to degree of superheating at an outlet of the evaporator, based on a sensor measurement result. The controller adjusts degree of subcooling to a second value larger than the first value when executing the first detection operation, and determines that refrigerant is leaking when the value related to discharge temperature of the compressor or the value related to degree of superheating is equal to or larger than a threshold value.

Abstract: An air conditioner has a heat source unit and a utilization unit, and includes a refrigerant circuit, a first detector, and a controller. The refrigerant circuit is configured by a compressor, a condenser, an expansion mechanism, and an evaporator being connected by a refrigerant pipe. The first detector detects the temperature or pressure of refrigerant in the refrigerant circuit. The controller starts the compressor during the non-operation of the compressor and executes a determination mode to determine the presence or absence of refrigerant leakage from the refrigerant circuit on the basis of a detection value of the first detector.

Abstract: An indoor unit is used in an air conditioner capable of executing a cooling operation by circulating a refrigerant. The indoor unit includes an indoor heat exchanger, a drain pan, a drain pump, and an indoor controller. The indoor heat exchanger (50) exchanges heat between the refrigerant and indoor air. The drain pan receives water generated in the indoor heat exchanger. The drain pump sucks up the water from the drain pan. At a time of executing the cooling operation, the indoor controller operates the drain pump when an evaporation temperature of the refrigerant in the indoor heat exchanger is equal to or lower than a dew point temperature of the indoor air. At the time of executing the cooling operation, the indoor controller controls the drain pump so as to have a period in which operation of the drain pump is not performed when the evaporation temperature of the refrigerant is higher than the dew point temperature.

Abstract: Provided is a method of controlling the regenerating condition by use of a construction machine having an upper revolving structure with a hybrid drive unit, and a lower traveling body, wherein when in a brake mode, the hydraulic motor is neutralized by the internal communication of an inlet port and an outlet port of the hydraulic motor via a communication valve, such that most of the kinetic (inertia) energy is efficiently transduced into electric energy by way of regenerative power generation for electric storage, and such that the switchover between driving and regenerative power generation is rendered in the optimal condition. The control unit determines the control mode of the control unit in accordance with the rotation direction of the hydraulic actuator, the operating direction of the hydraulic actuator controller, the actual rotational velocity of the hydraulic actuator, and the manipulated variable of the hydraulic actuator controller.