When the anomaly determination mode starts, the controller brings the decompressor into the first decompression amount state, and operates a compressor at a first speed. The controller is configured to store a value of the related physical quantity measured by the detector at a time point at which a first time elapses from a start of the anomaly determination mode, as a first measurement value, and thereafter switch the decompressor to the second decompression amount state from the first decompression amount state, store a value of the related physical quantity measured by the detector after the decompressor is switched to the second decompression amount state from the first decompression amount state, as a second measurement value, and determine that there is anomaly in the refrigerant circuit when a value obtained by subtracting the first measurement value from the second measurement value is larger than a first anomaly determination value.

A cryocooler includes a cold head, a plurality of compressor main bodies that are connected to the cold head in parallel, a plurality of state detection sensors that are provided to correspond to the plurality of compressor main bodies respectively and each detect a state of a corresponding compressor main body to output a state detection signal, and a compressor control unit that is configured to, in a case where the state detection signal from any one state detection sensor of the plurality of state detection sensors indicates that the corresponding compressor main body is stopped, stop also the other compressor main bodies.

A chiller includes an evaporator, a compressor including a prime mover, a first pressure sensor that detects a first pressure in the evaporator, a second pressure sensor that detects a second pressure in a condenser, and a controller. The controller determines a predicted energy level of the compressor based on the first pressure and the second pressure, the predicted energy level associated with liquid droplet flow into the compressor, compares the predicted energy level to an operating energy level, and modifies the at least one of the input power and the input current to the prime mover based on the comparison satisfying a modification condition.

A chiller assembly is provided. The chiller assembly includes a compressor (102), a condenser (106), an expansion device and an evaporator (108) connected in a closed refrigerant circuit. The chiller assembly further includes a motor (104) connected to the compressor to power the compressor, and a variable speed drive (110) connected to the motor to power the motor. The variable speed drive is operable to provide a variable voltage to the motor and a variable frequency to power the motor. The variable speed drive includes multiple sensors and an input current estimator that determines an estimated RMS input current based on sensor data received from the sensors. The chiller assembly further includes a control panel to control operation of the variable speed drive.

An HVAC system includes an unloading device, a centrifugal compressor, a gas foil bearing, a VFD and a controller. The controller is programmed to start the centrifugal compressor from a stopped condition by operating the unloading device to remove a load from the centrifugal compressor, accelerating the motor to a first speed above a liftoff speed of the gas foil bearing and below an operating speed of the centrifugal compressor, running the motor for a period of time, operating the unloading device to apply the load to the centrifugal compressor, and accelerating the motor to the operating speed.

The present disclosure relates to a method for determining an efficiency curve of a chiller that includes operating a chiller over a range of operating capacities, measuring a temperature of water entering the chiller at an initial capacity, measuring a temperature of water exiting the chiller at the initial capacity, measuring a power consumption of the chiller at the initial capacity, calculating an initial efficiency of the chiller at the initial capacity, measuring a plurality of temperatures of water entering the chiller at a plurality of capacities, measuring a plurality of temperatures of water exiting the chiller at each of the plurality of capacities, measuring a plurality of power consumptions at each of the plurality of capacities, calculating a plurality of efficiencies at each of the plurality of capacities, and generating an efficiency curve for the chiller with the initial efficiency and the plurality of efficiencies.

A shoe care apparatus including a chamber including an air inlet and an air outlet; a first duct connected to the air outlet and having an evaporator and a condenser arranged inside; a second duct connected to the first duct and the air inlet; a holder arranged in the chamber and connected to the air inlet; a fan configured to circulate air through the first duct, the second duct, the holder, the chamber; a compressor configured to discharge a refrigerant to the condenser; a first temperature sensor configured to measure a first temperature of air heated by the condenser; and a controller configured to determine a target temperature of the heated air based on the user input, operate the compressor at the operation frequency based on the target temperature and outside air temperature, and control the operation frequency of the compressor based on the target temperature and the first temperature.

A chiller system is provided and includes a compressor, a variable frequency drive (VFD) to drive the compressor at variable frequencies and a chiller controller to ascertain a chiller condition and to command the VFD to drive the compressor at one of the variable frequencies based on the chiller condition at a first sampling rate. The VFD is configured to drive the compressor at the one of the variable frequencies responsive to being commanded by the chiller controller, to ascertain the chiller condition at a second sampling rate, which is substantially higher than the first sampling rate, and to alert the chiller controller accordingly.

An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

A heat pump device includes an inverter control unit outputting PWM signals to an inverter; a current detection unit detecting a current value flowing in the inverter and outputting the current value after reducing a current value having a first frequency or higher in detected current value; and a drive-signal stop unit that, when the current value output from the current detection unit is equal to or larger than an interruption level, stops output of PWM signals to the inverter. Particularly, the inverter control unit generates a voltage command value such that the voltage command value becomes a value equal to or larger than a lower limit determined according to the first frequency and generates PWM signals based on generated voltage command value and a carrier signal, thereby causing a voltage output time to the motor to be a predetermined time or longer.