Abstract: A high-strength steel sheet having a tensile strength of 1,180 MPa or more, and specified chemical composition. The steel sheet includes a steel structure in which an area fraction of martensite having a carbon concentration of more than 0.7×[% C] and less than 1.5×[% C] is 55% or more, an area fraction of tempered martensite having a carbon concentration of 0.7×[% C] or less is 5% or more and 40% or less, a ratio of a carbon concentration in retained austenite to a volume fraction of retained austenite is 0.05 or more and 0.40 or less, and the martensite and the tempered martensite each have an average grain size of 5.3 ?m or less, where [% C] represents the content, by mass %, of compositional element C in steel.

Abstract: A refrigerant leakage management system includes a timer and a controller. The timer counts a non-operating period of a refrigeration cycle device. The controller determines whether or not the non-operating period of the refrigeration cycle device exceeds a predetermined first period. Upon determining that the non-operating period of the refrigeration cycle device exceeds the first period, the controller brings the refrigeration cycle device into operation or notifies an administrator of the refrigeration cycle device.

Abstract: A refrigerant leakage detection system includes a first controller, and a second controller. The first controller uses a first method to determine the presence or absence of refrigerant leakage from the refrigerant circuit. The second controller uses a second method different from the first method to determine the presence or absence of refrigerant leakage from the refrigerant circuit. The refrigerant leakage detection system determines the presence or absence of refrigerant leakage from the refrigerant circuit on the basis of the determination result of the first controller and the determination result of the second controller. The refrigerant leakage detection system determines that there is a refrigerant leakage in the refrigerant circuit if the first controller determines that there is a refrigerant leakage from the refrigerant circuit and the second controller determines that there is a refrigerant leakage from the refrigerant circuit.

Abstract: An air conditioning device includes a first indoor unit and a second indoor unit interlocking with a safety device as a countermeasure against refrigerant leakage. An installation assistance system for the air conditioning device determines interlock release states of the first indoor unit and the second indoor unit based on information on the air conditioning device, and outputs a determination result. The information on the air conditioning device is information indicating whether or not the first indoor unit and the second indoor unit are short-circuited with the safety device through an interlock line.

Abstract: An air conditioning system includes an air conditioning device, a detector, and an alarm. The air conditioning device has a control unit and conditions air in an indoor space. The detector detects the concentration of refrigerant in the indoor space. The alarm notifies of refrigerant leakage in the indoor space. The detector or the alarm transmits information indicating whether or not the detector and the alarm are connected to each other in a wired or wireless manner, to the control unit. The control unit inhibits operation of the air conditioning device when the information indicates that the detector and the alarm are not connected to each other in the wired or wireless manner.

Abstract: A refrigerant cycle system includes: a first refrigerant circuit that includes a first heat exchanger, a first compressor, and a first cascade heat exchanger and that is configured as a first vapor compression refrigeration cycle; a second refrigerant circuit that includes the first cascade heat exchanger, a second compressor, and a second heat exchanger and that is configured as a second vapor compression refrigeration cycle; a first unit that accommodates the first heat exchanger and the first compressor; a second unit that accommodates the first cascade heat exchanger and the second compressor; and a third unit that accommodates the second heat exchanger. The first unit, the second unit, and the third unit are disposed apart from each other. The first cascade heat exchanger performs heat exchange between a first refrigerant that flows through the first refrigerant circuit and a second refrigerant that flows through the second refrigerant circuit.

Abstract: An air conditioning system includes a refrigerant circuit, a heat exchanger, a shutoff valve, and a refrigerant leakage sensor. The refrigerant circuit includes a first part and a second part. The heat exchanger is provided in the first part and exchanges heat between a refrigerant and air in an air conditioning target space. The shutoff valve is provided in the refrigerant circuit and shuts off communication between the first part and the second part. The refrigerant leakage sensor detects that refrigerant concentration is within a first range and detects the refrigerant leaked from the first part. The shutoff valve is placed to set the refrigerant concentration in the air conditioning target space within a second range larger than the first range, when it is assumed that all the refrigerant present in the first part has leaked to the air conditioning target space.

Abstract: An air conditioning apparatus includes a refrigerant circuit, and includes a connecting portion, a circuit configuration portion, a first member, and a controller. To the connecting portion: a first electric wire connected to a first device of a plurality of safety devices including at least two types of a refrigerant detector, an alarm device, an isolation valve, and a ventilation device; and a second electric wire connected to a second device of a type different from the first device of the plurality of safety devices are connected. The circuit configuration portion forms an interlock circuit together with the first electric wire and the second electric wire connected to the connecting portion. The first member enables formation of a first circuit including at least part of the circuit configuration portion without going through the first electric wire and the second electric wire.

Abstract: An air conditioning indoor unit that blows air, which has exchanged heat with a refrigerant flowing through a heat exchanger, into an air conditioning target space, includes: a liquid refrigerant pipe and a gas refrigerant pipe that are connected to the heat exchanger; a casing that accommodates the heat exchanger and that has an opening communicating with the air conditioning target space; a first shutoff valve in the liquid refrigerant pipe; a second shutoff valve in the gas refrigerant pipe; and a partition wall that separates a first space from a second space in the casing. The first shutoff valve and the second shutoff valve are in the first space. The second space communicates with the air conditioning target space via the opening.

Abstract: Provided is a refrigeration apparatus in which adverse events caused by excess refrigerant can be suppressed even when defrosting is performed with some of a plurality of outdoor units designated as units to be defrosted. An air-conditioning apparatus is configured from a parallel connection of a first outdoor unit and a second outdoor unit, wherein when a second outdoor heat exchanger of the second outdoor unit is caused to function as an evaporator while a first outdoor heat exchanger of the first outdoor unit is caused to function as a condenser to defrost the first outdoor heat exchanger, a refrigerant circuit has a flow channel that supplies some of the refrigerant flowing out of the first outdoor heat exchanger to the second outdoor heat exchanger and a flow channel that supplies the rest of the refrigerant flowing out of the first outdoor heat exchanger to an indoor heat exchanger.

Abstract: In a case where the total volume of plural indoor heat exchangers is smaller than the volume of an outdoor heat exchanger, a control component performs a heating refrigerant charging operation until a heating refrigerant charging completion condition is met, and thereafter performs a cooling refrigerant charging operation until a refrigerant charging completion condition where a refrigerant circuit is charged with a prescribed quantity of refrigerant is met.

Abstract: When charging a refrigerant circuit with refrigerant, a control component starts a heating refrigerant charging operation that is performed by switching the refrigerant circuit to a heating cycle state and performs the heating refrigerant charging operation until a predetermined heating refrigerant charging completion condition is met. Thereafter, the control component switches to a cooling refrigerant charging operation that is performed by switching the refrigerant circuit to a cooling cycle state and performs the cooling refrigerant charging operation until a refrigerant charging completion condition where the refrigerant circuit is charged with a prescribed quantity of the refrigerant is met.

Abstract: In an air conditioning device (10) to which an outdoor unit (20) and indoor units (40) are connected, when a flow rate of a gaseous refrigerant in a gas main pipe (72a) is lower than a lower limit flow rate in main pipe, an amount of refrigerating machine oil accumulated in the gas main pipe (72a) is calculated. When gas branch pipes (72b) include a gas branch pipe (72b) having a flow rate lower than a lower limit flow rate in branch pipe even though the flow rate of the gaseous refrigerant in the gas main pipe (72a) is higher than the lower limit flow rate in main pipe, an amount of the machine oil accumulated in the gas branch pipe (72b) is calculated. When the amounts are integrated and the integrated value exceeds a set amount, oil collecting operation is performed.

Abstract: A refrigeration apparatus includes a compressor, a heat-source-side heat exchanger operable as a refrigerant evaporator or radiator, and a usage-side heat exchanger operable as a refrigerant evaporator or radiator. The heat-source-side heat exchanger is disposed inside a heat source unit having an exhaust port and an outdoor fan in an upper part, and an intake port in a side part. The heat-source-side heat exchanger includes first and second heat-source-side heat exchangers. Adjustable first and second heat-source-side flow rate adjusting valves are connected to liquid sides of the first and second heat-source-side heat exchangers, respectively. In a defrost operation in order to defrost the first and second heat-source-side heat exchangers, the opening degrees of the first and second heat-source-side flow rate adjusting valves are controlled so as to achieve a defrost flow rate ratio at which more refrigerant flows to the second heat-source-side heat exchanger than during an air-cooling operation.

Abstract: Provided is a refrigeration apparatus in which a decrease in a temperature of an indoor heat exchanger can be suppressed as much as possible while depletion of refrigerator oil in a compressor is also suppressed. An air-conditioning apparatus configured from a parallel connection of a plurality of outdoor units to an indoor unit, wherein when a predetermined defrosting condition has been fulfilled, a controller includes at least one processor programmed to selectively execute a reverse-cycle defrost mode when a predetermined outflow condition pertaining to an outflow integrated quantity of refrigerator oil has also been fulfilled, and selectively execute an alternating defrost mode, in which the outdoor unit that is to be defrosted is changed in sequence, when the predetermined outflow condition has not been fulfilled.

Abstract: A heat source unit includes a compressor, first and second heat exchangers connected in parallel, first and second motor-operated valves regulating amounts of refrigerant that flow to the first and second heat exchangers, first and second temperature sensors measuring temperatures of refrigerant flowing from the first and second motor-operated valve to the first and second heat exchangers, a discharge temperature sensor measuring temperature of refrigerant discharged from the compressor, and a valve opening controller. The controller regulates valve openings of the first and second motor-operated valves based on the discharge temperature, refrigerant temperature detected by the first temperature sensor and refrigerant temperature detected by the second temperature sensor.

Abstract: Provided is a refrigeration apparatus in which adverse events caused by excess refrigerant can be suppressed even when defrosting is performed with some of a plurality of outdoor units designated as units to be defrosted. An air-conditioning apparatus is configured from a parallel connection of a first outdoor unit and a second outdoor unit, wherein when a second outdoor heat exchanger of the second outdoor unit is caused to function as an evaporator while a first outdoor heat exchanger of the first outdoor unit is caused to function as a condenser to defrost the first outdoor heat exchanger, a refrigerant circuit has a flow channel that supplies some of the refrigerant flowing out of the first outdoor heat exchanger to the second outdoor heat exchanger and a flow channel that supplies the rest of the refrigerant flowing out of the first outdoor heat exchanger to an indoor heat exchanger.

Abstract: A multi-type air conditioning device controls an evaporation temperature and a condensing temperature, depending on required capacity of an indoor unit. The air conditioning device compares a current evaporation temperature or condensing temperature with a reference value, of an evaporation temperature or an condensing temperature, corresponding to a lower limit flow rate, of a gaseous refrigerant, required for refrigerating machine oil not to accumulate in, but to flow through, the gas branch pipes, and calculates an amount of the refrigerating machine oil accumulated in a gas branch pipe which does not satisfy the lower limit flow rate. When the calculated amount exceeds a set amount, the air conditioning device performs oil collecting operation, and controls the oil collecting operation in view of a flow rate of a gaseous refrigerant in gas branch pipes.

Abstract: When charging a refrigerant circuit with refrigerant, a control component starts a heating refrigerant charging operation that is performed by switching the refrigerant circuit to a heating cycle state and performs the heating refrigerant charging operation until a predetermined heating refrigerant charging completion condition is met. Thereafter, the control component switches to a cooling refrigerant charging operation that is performed by switching the refrigerant circuit to a cooling cycle state and performs the cooling refrigerant charging operation until a refrigerant charging completion condition where the refrigerant circuit is charged with a prescribed quantity of the refrigerant is met.

Abstract: In a case where the total volume of plural indoor heat exchangers is smaller than the volume of an outdoor heat exchanger, a control component performs a heating refrigerant charging operation until a heating refrigerant charging completion condition is met, and thereafter performs a cooling refrigerant charging operation until a refrigerant charging completion condition where a refrigerant circuit is charged with a prescribed quantity of refrigerant is met.