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.

A centrifugal compressor for a chiller system includes a casing having an inlet portion and an outlet portion, a recirculation structure including a recirculation path and a recirculation discharge cavity, an impeller disposed downstream of the recirculation discharge cavity, a plurality of recirculation discharge guide vanes disposed to surround the recirculation discharge cavity, and a diffuser disposed in the outlet portion downstream of the impeller. The recirculation structure is configured to impart a swirl to a flow of refrigerant into the inlet portion. The recirculation path supplies the refrigerant from the diffuser to the recirculation discharge cavity. The recirculation path includes a recirculation pipe that introduces the refrigerant toward the plurality of recirculation discharge guide vanes. An annular groove is disposed between the recirculation pipe and the plurality of recirculation discharge guide vanes. An annular plate is disposed between the annular groove and the recirculation discharge cavity.

A screw compressor includes a screw rotor having a plurality of screw grooves, a plurality of gate rotors each including gates that mesh with the screw rotor, and a casing. The screw rotor is rotatably inserted in the casing. The casing has a cylindrical wall through which the gates pass. The screw compressor has a plurality of compression chambers inside the cylindrical wall. The plurality of compression chambers are defined by the screw rotor and the gates. The compression chambers include a first compression chamber and a second compression chamber. A fluid introduced into the casing at a suction pressure is compressed to an intermediate pressure higher than the suction pressure in the first compression chamber. The fluid at the intermediate pressure is compressed to a discharge pressure higher than the intermediate pressure in the second compression chamber.

A refrigeration cycle device includes a compressor. The compressor includes a casing, a driving unit disposed in the casing, a compression unit coupled to the driving unit and configured to compress a refrigerant, and a valve configured to control a flow of the refrigerant in the casing. The valve includes a valve chamber including a main flow path in which the refrigerant is to flow, the main flow path including a refrigerant inlet and a refrigerant outlet. The valve also includes a floating body disposed in the valve chamber to open or close the main flow path, and a bypass flow path formed in the valve chamber and which is to be opened or closed by the floating body. When the driving unit is stopped and the bypass flow path is opened by the floating body, the refrigerant is to be detoured to the bypass flow path.

A scroll compressor includes: a shell; a compression mechanism unit accommodated in the shell and defining a compression chamber, the compression mechanism unit having a discharge port through which a discharge chamber and the compression chamber communicate with one another; a discharge valve mechanism that opens and closes the discharge port. The discharge valve mechanism includes a valve seat provided on an outlet portion of the discharge port and a valve and closes the valve seat when sitting on the valve seat. The valve seat includes an annular portion serving as an edge of an opening of the outlet portion and a valve supporting portion that is provided in a region surrounded by the inner circumference of the annular portion and divides the opening of the outlet portion into plural valve seat holes. The valve is in contact with at least a portion of the valve supporting portion and with the annular portion, when sitting on the valve seat.

The motor driving apparatus includes a switch that is a mechanical switch for changing coil connection states of a motor; an inverter that generates alternating voltage from direct voltage and outputs the alternating voltage to the motor; and a control device that controls the switch and the inverter. The control device causes the switch to change the coil connection states while the alternating voltage output from the inverter is zero.

A turbo chiller that has an oil-free configuration, which reduces the frequency of maintenance and maintenance-induced release of refrigerant, and can achieve a reduced environmental impact by utilizing the characteristics of the low-pressure refrigerant R1233zd(E) that reaches negative pressure at a saturation temperature of 18° C. or lower. The turbo chiller comprises a refrigeration cycle that includes a turbo compressor, a condenser, a decompression device, and an evaporator connected in sequence via piping and is filled with a refrigerant; wherein the refrigerant is a low-pressure refrigerant R1233zd(E) refrigerant with low global warming potential and low ozone depletion potential; the turbo compressor has a direct drive configuration in which a rotating shaft of impellers is directly joined to a motor; and the rotating shaft is supported by magnetic bearings.

A DC power supply device includes: a rectifier circuit; a reactor connected at one end to one output terminal of the rectifier circuit; a charging unit including a first and second switching element connected in series between another end of the reactor and another output terminal of the rectifier circuit, the charging unit configured to charge a first and second capacitor connected in series between output terminals to which a load is connected; and a control unit that controls the charging unit. The control unit sets, based on the timing at which the zero-crossing occurs, a dead time in which both the and second switching element are off, and when states of the first and second switching element at a time of occurrence of the zero-crossing match a predetermined set of states, reverses the states of the first switching element and the second switching element.

According to one embodiment, a horizontal compressor comprises a container accommodating a compression mechanism unit and an electric motor unit, a first leg fixed to the container near the motor unit, a second leg fixed to an end of the container on the compression mechanism unit side, an accumulator between the legs, and a joint port in the container. The second leg includes a first support portion supporting the container in a horizontal attitude, and a second support portion supporting the container standing in a vertical attitude. The first support portion extends in a direction away from the joint port relative to the second support portion.

An aircraft having an engine, a cabin, an air conditioning system collecting the hot air from the engine, so as to treat the hot air, regulate a temperature of the hot air and send the hot air towards the cabin via a main line, an air line channeling the air leaving the cabin, and an arrangement for cooling the engine using the air thus drawn off by the air line. By drawing off the air at the outlet of the cabin, the performance of the engine is improved and the fuel consumption is reduced.