Abstract: A rotary compressor includes: a closed upright cylindrical compressor housing including an upper portion provided with a discharge section of refrigerant and a body portion provided with an intake section of the refrigerant; a compression section disposed at a lower part in the compressor housing and configured to compress the refrigerant suctioned by the intake section to discharge the refrigerant from the discharge section; and a motor disposed at an upper part in the compressor housing and configured to drive the compression section. The motor has a rotor disposed on an inner side and a stator disposed on an outer side, the refrigerant is HFO1123 refrigerant or a refrigerant mixture containing the HFO1123 refrigerant, and an inner welded portion formed by welding using flux is provided within a projection area of the rotor at the upper portion of the compressor housing.

Abstract: A heat exchanger includes: a heat transfer pipe in which refrigerant flows; and a spiral groove formed at an inner peripheral surface of the heat transfer pipe. A height of an inner wall of the groove in a radial direction of the heat transfer pipe is equal to or greater than 0.1 [mm], and when a wetted edge length of the heat transfer pipe is S, an inclination angle between a pipe axis direction of the heat transfer pipe and a longitudinal direction of the groove in a section of the heat transfer pipe parallel with the pipe axis direction is ?, and a length of the heat transfer pipe is L, the inclination angle ? is an acute angle, and a wetted area S×L/cos ? of the heat transfer pipe satisfies S×L/cos ??0.5 [m2].

Abstract: A rotary compressor includes: a closed upright cylindrical compressor housing including an upper portion provided with a discharge section of refrigerant and a body portion provided with an intake section of the refrigerant; a compression section disposed at a lower part in the compressor housing and configured to compress the refrigerant suctioned by the intake section to discharge the refrigerant from the discharge section; and a motor disposed at an upper part in the compressor housing and configured to drive the compression section. The motor has a rotor disposed on an inner side and a stator disposed on an outer side, the refrigerant is HFO1123 refrigerant or a refrigerant mixture containing the HFO1123 refrigerant, and an inner welded portion formed by welding using flux is provided within a projection area of the rotor at the upper portion of the compressor housing.

Abstract: A heat exchanger includes: a heat transfer pipe in which refrigerant flows; and a spiral groove formed at an inner peripheral surface of the heat transfer pipe. A height of an inner wall of the groove in a radial direction of the heat transfer pipe is equal to or greater than 0.1 [mm], and when a wetted edge length of the heat transfer pipe is S, an inclination angle between a pipe axis direction of the heat transfer pipe and a longitudinal direction of the groove in a section of the heat transfer pipe parallel with the pipe axis direction is —0, and a length of the heat transfer pipe is L, the inclination angle ? is an acute angle, and a wetted area S×L/cos ? of the heat transfer pipe satisfies S×L/cos ??0.5 [m2].

Abstract: In a power conversion system in which one or more converter cells are connected in series to form an arm for each phase, a control device includes a voltage command generating unit for generating a positive arm voltage command and a negative arm voltage command for each phase. The voltage command generating unit includes an AC current control unit, a circulating current control unit, and a command distributing unit. On the basis of inputted voltage commands, the command distributing unit subtracts voltage drop portions due to inductance values in the arms from respective voltages assigned as outputs of the positive arm and the negative arm, to distribute voltage components, thereby determining the positive arm voltage command and the negative arm voltage command.

Abstract: A mixture refrigerant includes: 50 wt. % to 70 wt. % of R32, R1234ze, and R125. An air conditioner includes a mixture refrigerant containing 50 wt. % to 70 wt. % of R32, R1234ze, and R125.

Abstract: A heat pump apparatus includes: a refrigerant circuit which includes a compressor, an utilization-side heat exchanger, a first expansion valve, and an outdoor heat exchanger; an injection pipe which includes a solenoid switching valve and a second expansion valve; and an objective supercooling degree table which stores objective supercooling degrees according to condensing pressure in the refrigerant circuit and rotation number of the compressor. In the heat pump apparatus, liquid refrigerant is injected to the compressor by way of the injection pipe. The heat pump apparatus switches between a first case where the liquid refrigerant is injected to the compressor and a second case where the liquid refrigerant is not injected, and a value of the objective supercooling degree is changed between the first case and the second case to control the first expansion valve based on the value of the objective supercooling degree.

Abstract: A heat pump apparatus includes: a refrigerant circuit which includes a compressor, a utilization-side heat exchanger for exchanging heat between water and refrigerant, an electronic expansion valve, and an outdoor heat exchanger; a controller which controls the compressor and the electronic expansion valve; a subcooling value calculating unit which calculates a subcooling value of the refrigerant circuit; a condensing pressure detector which detects condensing pressure of the compressor; a compressor rotation number detector which detects rotation number of the compressor; and an objective subcooling value extracting unit which selects and extracting an objective subcooling value stored in advance, from the condensing pressure and the rotation number of the compressor. The controller adjusts an opening degree of the electronic expansion valve so that the calculated subcooling value of the refrigerant circuit reaches the objective subcooling value.

Abstract: A heat pump apparatus includes: a refrigerant circuit which includes a compressor, a utilization-side heat exchanger for exchanging heat between water and refrigerant, an electronic expansion valve, and an outdoor heat exchanger; a controller which controls the compressor and the electronic expansion valve; a subcooling value calculating unit which calculates a subcooling value of the refrigerant circuit; a condensing pressure detector which detects condensing pressure of the compressor; a compressor rotation number detector which detects rotation number of the compressor; and an objective subcooling value extracting unit which selects and extracting an objective subcooling value stored in advance, from the condensing pressure and the rotation number of the compressor. The controller adjusts an opening degree of the electronic expansion valve so that the calculated subcooling value of the refrigerant circuit reaches the objective subcooling value.

Abstract: A heat pump apparatus includes: a refrigerant circuit which includes a compressor, an utilization-side heat exchanger, a first expansion valve, and an outdoor heat exchanger; an injection pipe which includes a solenoid switching valve and a second expansion valve; and an objective supercooling degree table which stores objective supercooling degrees according to condensing pressure in the refrigerant circuit and rotation number of the compressor. In the heat pump apparatus, liquid refrigerant is injected to the compressor by way of the injection pipe. The heat pump apparatus switches between a first case where the liquid refrigerant is injected to the compressor and a second case where the liquid refrigerant is not injected, and a value of the objective supercooling degree is changed between the first case and the second case to control the first expansion valve based on the value of the objective supercooling degree.