Abstract: A model generation apparatus according to one aspect of the present invention acquires a plurality of learning datasets each constituted by a first sample of a first time of predetermined data obtained in time series and feature information included in a second sample of the predetermined data of a future second time relative to the first time, and trains a prediction model, by machine learning, to predict feature information of the second time from the first sample of the first time, for each learning dataset. In the model generation apparatus, a rarity degree for is set each learning dataset, and, in the machine learning, the model generation apparatus trains more preponderantly on learning datasets having a higher rarity degree.

Abstract: A freezing device including a compressor that compresses sucked refrigerant using a compression mechanism and discharges compressed refrigerant includes a compressor, an inverter, and a controller. The compressor includes a motor, a low pressure unit, a compression space, a high pressure unit, a communication flow path, and a flow control valve. The inverter drives or stops the motor. The controller controls the inverter and the flow control valve. The controller performs, in stop control in which an operation of the compressor is stopped, braking control in which driving of the compression mechanism is prevented or suppressed, and pressure equalization control in which pressure in the high pressure unit is equalized with pressure in the low pressure unit.

Abstract: A refrigeration cycle apparatus comprises: a refrigerant cycle circuit, a condenser, a pressure-reducing device and an evaporator are sequentially connected by pipes; an injection circuit that branches off from the refrigerant cycle circuit between the condenser and the pressure-reducing device and is connected to the injection flow passage; a flow rate control device provided in the injection circuit or the injection flow passage; and a controller configured to control the flow rate control device. At a time of starting up the compressor, the controller, controls regardless of a temperature of refrigerant discharged from the compressor, the flow rate control device so as to supply refrigerant liquid to the compression chamber via the injection circuit and the injection flow passage until an operating capacity of the compressor reaches a preset operating capacity or until a preset time elapses after starting up the compressor.

Abstract: A freezing device including a compressor that compresses sucked refrigerant using a compression mechanism and discharges compressed refrigerant includes a compressor, an inverter, and a controller. The compressor includes a motor, a low pressure unit, a compression space, a high pressure unit, a communication flow path, and a flow control valve. The inverter drives or stops the motor. The controller controls the inverter and the flow control valve. The controller performs, in stop control in which an operation of the compressor is stopped, braking control in which driving of the compression mechanism is prevented or suppressed, and pressure equalization control in which pressure in the high pressure unit is equalized with pressure in the low pressure unit.

Abstract: A screw compressor includes an internal-volume-ratio variable mechanism including a variable Vi valve configured to make a Vi value being an internal volume ratio variable. The screw compressor controls a position of the variable Vi valve in two stages. The position of the variable Vi valve when the Vi value is set to be large is set to attain a Vi value with which a compressor efficiency during operation under a predetermined high-load condition or a predetermined high-compression-ratio condition is equal to or higher than a set efficiency set in advance.

Abstract: The present invention provides a screw compressor in which an oil path is provided within the casing body such that the oil for sealing gaps in the compression chamber and lubricating the bearings is circulated to the vicinity of the low pressure side, allowing the compressor to have high adiabatic efficiency and high volumetric efficiency. The present invention also provides a screw compressor in which an oil path is provided in the screw bore outer circumferential portion of the casing body to prevent contact between the screw rotor and the screw bore portion of the casing body. The present invention also provides a screw compressor which includes a heat sink to increase the heat transfer area for exchanging heat between the oil and refrigerant gas or liquid refrigerant, thereby achieving increased resistance to returned liquid refrigerant.