To reduce the possibility that temperature of refrigerant discharged from a compressor of a refrigeration apparatus becomes excessively high by controlling torque of a motor built into the compressor, the compressor includes the motor having rotation thereof controlled by inverter control. An inverter controller controls torque of the motor using inverter control when operation frequency of the compressor is at least one value within a range of from 10 Hz to 40 Hz. When at least the operation frequency is within the range of from 10 Hz to 40 Hz, torque of the motor is controlled, and under a predetermined condition in which temperature of refrigerant discharged from the compressor easily becomes excessively high, a device controller controls devices provided in a refrigerant circuit such that refrigerant sucked into the compressor is placed in a wet vapor state.

A refrigeration cycle apparatus includes a refrigerant circuit including a compressor, a condenser (outdoor heat exchanger), an expansion valve, and an evaporator (indoor heat exchanger), a fan configured to blow air to the condenser, a fan configured to blow air to the evaporator, and a controller configured to control at least one of a frequency of the compressor, an opening degree of the expansion valve, a rotation speed of the fan, and a rotation speed of the fan, such that the refrigerant sucked into the compressor has a quality of 1.0 or greater. The refrigerant circuit is configured for use with a refrigerant mixture inclusive of 30 wt % to 50% wt ethylene-based hydrofluorocarbon refrigerant.

A controller controls a first air-conditioning system and a second air-conditioning system having separate refrigerant circuits, but arranged for conditioning a common space. The controller includes a multi-variable regulator to determine control signals for controlling operations of first components of the first and the second refrigerant circuits to reduce jointly and concurrently an environmental error between setpoint and measured values of environment in the common space. The controller also includes at least two single-variable regulators to receive operational errors between setpoint and measured values of an operation of a second component of the first and the second refrigerant circuits. The controller separately determines control signals for controlling the operation of different refrigerant circuits that reduce the operational errors. The controller also includes a lookup table that stores values for other inputs of the systems that improve its performance, and which selects specific input values for both systems according to the outputs of the multi-variable and/or single variable regulators. The controller includes an electrical circuit for controlling the first and the second air-conditioning systems according to the determined control signals.

A refrigeration cycle system includes a refrigeration cycle apparatus, an operation signal transmitter, a detection unit, a notification unit, and a processing unit. The refrigeration cycle apparatus includes a refrigerant circuit. The operation signal transmitter transmits an operation signal for the refrigeration cycle apparatus. The detection unit detects leakage of a refrigerant. The notification unit notifies of leakage of the refrigerant by emitting at least one of sound and light in a case in which the detection unit has detected leakage of the refrigerant. The processing unit causes the notification unit to execute test behavior of emitting at least one of sound and light in a case in which the operation signal transmitter transmits the operation signal to the refrigeration cycle apparatus.

The air conditioner has: an outdoor heat exchanger that exchanges heat between the air and a refrigerant flowing in the interior of this heat exchanger; an outdoor fan that blows air into the outdoor heat exchanger; an outdoor fan motor that rotationally drives the outdoor fan; an outdoor fan inverter that supplies a desired current to the outdoor fan motor; a current detector that detects the current flowing in the outdoor fan motor; and a control unit that controls the outdoor fan inverter such that the rotational frequency of the outdoor fan motor reaches a target rotational frequency. The control unit starts a defrosting operation of the outdoor heat exchanger on the basis of a detection value from the current detector during the heating operation.

An outdoor fan motor driving device and an air conditioner including an outdoor fan motor driving device are provided, which may include an inverter to convert DC power into AC power according to a switching operation and to output the converted AC power to an outdoor fan motor, an output current detector to detect phase currents flowing in the outdoor fan motor, and a controller to control the inverter based on the detected phase currents. When the outdoor fan motor is rotated by external wind, in a state in which all of lower arm switching elements, among upper arm switching elements and lower arm switching elements of the inverter, are turned on before the outdoor fan motor is driven, with the result that levels of the phase currents flowing in the outdoor fan motor are between a first level and a second level, the controller may control the outdoor fan motor such that a rotational speed of the outdoor fan motor is increased while the outdoor fan motor is rotated in a first direction and then rotated in a second direction opposite to the first direction during a speed increase period of the outdoor fan motor after an alignment period during which a rotor of the outdoor fan motor is aligned when the outdoor fan motor is driven.

A vehicle air conditioning apparatus can ensure that the temperature of the air supplied to the vehicle interior is a preset temperature by securing the quantity of heat release for the radiator during a cooling and dehumidifying operation. The valve opening of the condensing pressure regulating part of the first control valve is smaller when the calculated opening SW of the air mix damper is equal to or more than the predetermined value than when the opening SW is smaller than the predetermined value. Accordingly, when the quantity of heat release is not sufficient in the radiator, it is possible to increase the condensing pressure of the refrigerant in the radiator to raise the temperature of the refrigerant in the radiator. Consequently, it is possible to secure the amount of heating, and therefore to ensure that the temperature of the air supplies to the vehicle interior is a preset temperature.

A method for defrosting a heat pump includes operating a fan at a particular speed. The fan is positioned to circulate air across the exterior coil of the heat pump. The method also includes measuring a power of the fan while the fan is operating at the particular speed and initiating a defrost of the exterior coil of the heat pump when the power of the fan is less than a threshold power.

A CPU 210 receives suction pressure PL and a suction temperature Te, calculates a saturation temperature corresponding to the evaporation pressure Ts1 by using the suction pressure PL, and calculates a suction superheating degree SHs of a compressor 21 by using the suction temperature Te and the saturation temperature corresponding to the evaporation pressure Ts1. The CPU 210 reads a current opening degree De of an outdoor expansion valve 24. Next, the CPU 210 uses the received suction pressure PL and opening degree De of the outdoor expansion valve 24 and the calculated suction superheating degree SHs, refers to an outdoor fan control table 300, and determines a control aspect of an outdoor fan 27. The CPU 210 executes control of the outdoor fan 27 in accordance with the control aspect that is determined by referring to an outdoor fan control table 300.

In a split system heat pump cooling and heating system, an auxiliary hot water storage tank is provided as an energy storage bank. Two sets of coils run through this storage tank, a first set carrying hot refrigerant from the heat pump to deposit energy and a second set carrying hot potable water to remove energy. Valve and switch matrixes are operated at the heat pump to provide hot potable water from the energy storage bank during both normal space heating and cooling operations of the heat pump.