An operation controlling apparatus of a reciprocating compressor includes: a detector configured to detect a torque output by a motor of the reciprocating compressor, a rotation speed of the motor, a counter electromotive voltage of the motor, and a current applied to the motor; a controller configured to determine a mode switching time point for switching an operation mode of the reciprocating compressor based on the torque, the rotation speed, the counter electromotive voltage, and the current of the motor, and output a control signal for changing a wire ratio of the motor corresponding to the operation mode; and a driver configured to change the wire ratio of the motor based on the control signal and operate the reciprocating compressor in the operation mode among at least two operation modes.

A multi-air conditioner for cooling and heating is provided to remove latent heat and sensible heat by using a single outdoor unit. The multi-air conditioner includes: at least one indoor unit installed in a room, that comprises an indoor heat exchanger and an indoor expansion valve; an outdoor unit connected to the indoor unit via a refrigerant pipeline, that comprises an outdoor heat exchanger, a plurality of compressors, an outdoor expansion valve, and a four-way valve; and a dedicated outdoor air ventilation unit connected to the indoor unit and the outdoor unit via the refrigerant pipeline, that dehumidifies and ventilates outdoor air and supplies the outdoor air to the room, wherein the outdoor unit provides a refrigerant to both the dedicated outdoor air ventilation unit and the indoor unit by controlling the compressors depending on an operation mode of the dedicated outdoor air ventilation unit and the indoor unit. Accordingly, it is possible to run an air conditioner for cooling and heating and a dedicated outdoor air conditioner simultaneously by using a single outdoor unit. Moreover, the handling of sensible and latent heats can be controlled by a single outdoor unit, thereby minimizing facility costs and enhancing control reliability.

A liquefied gas cooling apparatus including: a gas flow path for carrying a liquefied gas that is liquefied by cooling; and a refrigeration unit including a refrigerating cycle formed by a compressor, a cooling unit, and an expander. The compressor is driven through an electric motor contained in a sealed housing together with a compressor mechanism.

A refrigerator includes a temperature sensor provided in a storage space of the refrigerator to detect a temperature; an inverter compressor constituting a freezing cycle for cooling the storage space, the number of rotations being variable by frequency control; and a controller for controlling the operation of the inverter compressor. The controller may variably control the operating frequency of the inverter compressor according to the load of the storage space in order to maintain the storage space at a set temperature, and compare the operating frequency with a stop frequency when a stop signal is input, when the operating frequency is lower than the stop frequency, raise the frequency of the inverter compressor to the stop frequency, and then stop the inverter compressor.

An air conditioner includes a main control unit, and a motor-driving control unit. The main control unit transmits, at every first time, an instruction for rotating the motor to the motor-driving control unit. The motor-driving control unit outputs, on the basis of the instruction, an instruction for rotating the motor to the inverter output unit. When the motor-driving control unit does not receive a new instruction for rotating the motor from the main control unit before the first time elapses from a time when the motor-driving control unit receives the instruction for rotating the motor from the main control unit last, the motor-driving control unit outputs an instruction for continuing operation based on the instruction for rotating the motor received from the main control unit at an immediately preceding time to the inverter output unit.

Method for optimizing the energy consumption of a refrigeration unit, comprising: a step A: activating a driving device (14) of the compressor (13) by modulating the operating voltage Vout of the compressor (13) to an optimized value designed to activate the compressor (13) at an optimized speed determined by a thermodynamic optimization algorithm; a step B: regulating the driving device (14) which drives the AC/DC converter (17) so that the bus voltage is equal to the greater between a first threshold and a second threshold; wherein the first threshold is equal to the product of √2 by the value of the supply voltage and the second threshold is equal to the product of √2 by the value of the driving voltage; a step C: modifying the speed of each fan in order to minimize the value of an overall electrical consumption.

A heat transport system includes: a refrigerant circuit that seals therein a fluid including HFC-32 and/or HFO refrigerant as a refrigerant and that includes: a refrigerant booster that boosts the refrigerant; an outdoor air heat exchanger that exchanges heat between the refrigerant and outdoor air; a medium heat exchanger that exchanges heat between the refrigerant and a heat transfer medium; and a refrigerant flow path switch that switches between a refrigerant radiation state and a refrigerant evaporation state; and a medium circuit that seals carbon dioxide therein as the heat transfer medium.

Certain example embodiments provide a vapor compression refrigeration system, comprising: a compressor configured to suction refrigerant at a low pressure and temperature from a suction return, compress the refrigerant, and output refrigerant at a higher pressure and temperature; a condenser configured to cool refrigerant received from the compressor as the refrigerant passes though coils in the condenser; an expansion device configured to reduce the pressure of the refrigerant received from the condenser; and an evaporator configured to allow the refrigerant received from the expansion device to absorb heat surrounding the evaporator. The system may include a plurality of sensors configured to measure temperature of the system and a controller configured to control, based on the signals from one or more sensors, operation of the compressor and/or an evaporator fan motor configured to allow the refrigerant received from the expansion device to absorb heat surrounding the evaporator.

A motor driving device that drives a motor with an alternating-current power converted from a direct-current power supply, includes an inverter that receives a pulse-width modulation signal and supplies the alternating-current power to the motor, and an inverter control unit that generates the pulse-width modulation signal and supplies the pulse-width modulation signal to the inverter. The inverter control unit reduces the number of pulses of the pulse-width modulation signal generated during a first period within one period of a mechanical angle of the motor to be lower than the number of pulses of the pulse-width modulation signal generated during a second period within the one period of the mechanical angle of the motor. The first period is a period during which a load torque is lower than a load torque during the second period.

The present disclosure relates to a heating, ventilation, and air conditioning (HVAC) unit having a vapor compression circuit including a compressor and a heat exchanger. The HVAC unit includes a controller configured to provide a first signal to control the compressor, and provide a second signal to control a variable speed fan associated with the heat exchanger based on a target speed. The HVAC unit further includes a pressure activated device coupled between the controller and the compressor, wherein the pressure activated device is configured to temporarily block the first signal from the controller while a refrigerant pressure within the vapor compression circuit is greater than a threshold value. In response to determining that the pressure activated device has blocked the first signal for at least a threshold time period, the controller is configured to both deactivate the first signal and provide the second signal for an equilibration time.