Abstract: An air-conditioning apparatus includes: a heat source unit that generates a heating energy or a cooling energy that is transferred to refrigerant; a heat-use unit that causes the refrigerant to transfer the heating energy or the cooling energy to a heat load through heat exchange between the refrigerant and the heat load; a plurality of return pipes arranged parallel to each other and connecting the heat source unit and the heat-use unit to allow the refrigerant to flow therein from the heat-use unit to the heat source unit; an opening and closing device provided at at least one of the return pipes to control a flow rate of refrigerant; and a controller that opens the opening and closing device in a cooling operation, and closes the opening and closing device in a heating operation.

Abstract: An air-conditioning apparatus includes a refrigerant circuit in which a compressor, a refrigerant flow switching device, a heat source side heat exchanger, an expansion device, a heat medium heat exchanger, and an accumulator are connected, a heat medium circuit in which a pump, the heat medium heat exchanger, a heat medium flow control device, and a load side heat exchanger are connected, at least one or more bypass pipes provided in the refrigerant circuit so that the refrigerant discharged from the compressor bypasses at least either one of the heat source side heat exchanger and the heat medium heat exchanger, a bypass opening and closing device provided at the bypass pipe, and a controller configured to control the bypass opening and closing device to carry out a start-up control function of causing low-pressure gas refrigerant with a high degree of superheat to flow into the accumulator.

Abstract: A heat medium relay device includes a valve block provided in a third space, and including a plurality of valves to allow a secondary heat medium subjected to the heat exchange at a first heat exchanger and a secondary heat medium subjected to the heat exchange at a second heat exchanger to flow to at least one indoor unit, the valve block being lighter in weight than each of the first heat exchanger, a first pump, the second heat exchanger, and a second pump.

Abstract: A relay unit includes a housing having a lower portion having four side faces each having an outlet; a heat exchanger accommodated in the housing; and a drain pan located below the heat exchanger. At a front face of the lower portion of the housing, a removable sheet metal cover having the outlet is formed. The drain pan includes a plate having four side portions, a side wall portion extending upward from each of the four side portions, and a drain socket provided in the side wall portion located forward or rearward, and to which a drain hose is connected. The drain pan is freely inserted and removed in a front-rear direction in a state in which the sheet metal cover is removed from the housing, and the drain pan is freely reversed front to rear to be accommodated in the housing.

Abstract: An air-conditioning apparatus includes: a heat source-side system having an intermediate heat exchanger that causes heat exchange to be performed between a heat source-side heat medium and a use-side heat medium, causes the heat source-side heat medium to receive or transfer heat, and causes the use-side heat medium to undergo a phase change; and a use-side cycle circuit formed of pipes connecting, to one another, the intermediate heat exchanger, a pump that sucks and delivers the use-side heat medium in a liquid state, a use-side heat exchanger that heats or cools air in an air-conditioning target space due to heat exchange causing a change in phase of the use-side heat medium, and a pressure-reducing device that reduces a pressure of the use-side heat medium that passes through the use-side heat exchanger, the use-side cycle circuit causing the use-side heat medium to circulate through the use-side cycle circuit.

Abstract: A refrigeration cycle apparatus includes a main circuit and a bypass circuit. The main circuit includes: a compressor; a first condenser; a first refrigerant-to-refrigerant heat exchanger; a first expansion device; a first branching portion; a first evaporator; a third branching; and a fourth branching portion. The bypass includes: a second expansion device; the first refrigerant-to-refrigerant heat exchanger; and a second branching portion. The second branching portion includes a liquid outflow pipe and a gas outflow pipe. The liquid outflow pipe defines one outlet for the refrigerant and is located below the gas outflow pipe. The gas outflow pipe defines another outlet for the refrigerant and is located above the liquid outflow pipe. The one outlet of the second branching portion communicates with the third branching portion. The other outlet of the second branching portion communicates with the fourth branching portion.

Abstract: A relay unit includes: a heat medium heat exchanger; a casing; a first refrigerant pipe connection port connected to one of two refrigerant pipes through which refrigerant circulates between the heat medium heat exchanger and the heat source side unit; a second refrigerant pipe connection port connected to an other of the refrigerant pipes; a first heat medium pipe connection port connected to one of two heat medium pipes through which a heat medium circulates between the heat medium heat exchanger and the load side unit; and a second heat medium pipe connection port connected to an other of the heat medium pipes. The first refrigerant pipe connection port, the second refrigerant pipe connection port, the first heat medium pipe connection port, and the second heat medium pipe connection port are provided on a top surface of the casing and face in a direction opposite to a direction of gravity.

Abstract: An air-conditioning apparatus includes: an outdoor unit including a compressor, and an outdoor heat exchanger; a first indoor unit including a first indoor heat exchanger; a relay unit including a relay heat exchanger through which the refrigerant exchanges heat with a heat medium different from the refrigerant, and a pump; and a second indoor unit including a second indoor heat exchanger, wherein the first indoor unit is installed in a first air-conditioned space, the second indoor unit is installed in a second air-conditioned space, the first air-conditioned space has a volume such that a concentration of the refrigerant in the first air-conditioned space is lower than a reference value even when a total amount of the refrigerant filled in the refrigerant circuit leaks in the first air-conditioned space, and a volume of the second air-conditioned space is smaller than the volume of the first air-conditioned space.

Abstract: An air-conditioning apparatus includes: an indoor unit configured to cool or heat an air-conditioning target space; an outdoor unit configured to supply heating energy or cooling energy to the indoor unit; a refrigerant shut-off unit configured to shut off supply of refrigerant to the indoor unit; a refrigerant sensor configured to detect refrigerant leaking from the indoor unit; a space detector configured to detect information regarding a volume of a space where the indoor unit is installed; and a controller configured to determine whether or not the space where the indoor unit is installed is a small space based on a detection result from the space detector, and energize the refrigerant sensor when the space where the indoor unit is installed is the small space.

Abstract: An air-conditioning apparatus includes an outdoor unit including a compressor configured to compress refrigerant, a relay unit connected to the outdoor unit, and an indoor unit connected to the relay unit. The compressor is driven to circulate the refrigerant between the outdoor unit, the relay unit, and the indoor unit. The air-conditioning apparatus includes a supplementary heat source unit in parallel with the indoor unit and connected to the relay unit. The outdoor unit includes an outdoor heat exchanger configured to exchange heat between the refrigerant flowing through the outdoor heat exchanger and a fluid. The supplementary heat source unit includes a supplementary heat exchanger configured to exchange heat between the refrigerant flowing through the supplementary heat exchanger and hot water.

Abstract: A refrigeration cycle apparatus includes a main circuit and a bypass circuit. The main circuit includes: a compressor; a first condenser; a first refrigerant-to-refrigerant heat exchanger; a first expansion device; a first branching portion; a first evaporator; a third branching; and a fourth branching portion. The bypass includes: a second expansion device; the first refrigerant-to-refrigerant heat exchanger; and a second branching portion. The second branching portion includes a liquid outflow pipe and a gas outflow pipe. The liquid outflow pipe defines one outlet for the refrigerant and is located below the gas outflow pipe. The gas outflow pipe defines another outlet for the refrigerant and is located above the liquid outflow pipe. The one outlet of the second branching portion communicates with the third branching portion. The other outlet of the second branching portion communicates with the fourth branching portion.

Abstract: An air conditioning apparatus includes a plurality of third heat exchangers and flow rate control valves. In a heating mode, a controller opens a flow rate control valve corresponding to a heat exchanger that is being requested to perform air conditioning of the plurality of third heat exchangers, and closes a flow rate control valve corresponding to a heat exchanger that is not being requested to perform air conditioning of the plurality of third heat exchangers. In a defrosting mode, when a temperature of a second heat medium is lower than a first determination temperature, the controller opens a flow rate control valve corresponding to at least one of the heat exchangers that are not being requested to perform air conditioning. The at least one of the heat exchangers is assigned a higher priority than a remaining heat exchanger that is not being requested to perform air conditioning.

Abstract: A refrigeration cycle device with a main circuit, a bypass circuit and a supercooling heat exchanger further includes: a controller to control an opening degree of the bypass expansion valve; a first sensor to detect a temperature at the refrigerant inflow side of the evaporator; and a second sensor to detect a pressure of the non-azeotropic mixed refrigerant flowing from the evaporator, wherein the controller controls the opening degree of the bypass expansion valve using temperatures of the evaporator, that is, the temperature at the refrigerant inflow side and a saturated gas temperature of the non-azeotropic mixed refrigerant calculated from the pressure so as to adjust a flow rate of the non-azeotropic mixed refrigerant flowing into the evaporator, to eliminate the temperature difference in the evaporator for suppressing uneven frost formation on the evaporator, and thus to prevent heat exchange performance from degrading.

Abstract: An air-conditioning apparatus includes a primary-side circuit in which a compressor, a first flow switching device, an outdoor heat exchanger, a second flow switching device, a first expansion device, and a relay heat exchanger are connected by pipes and in which refrigerant circulates; a secondary-side circuit in which the relay heat exchanger, a pump, a plurality of indoor heat exchangers, and heat medium flow control devices are connected by pipes and in which a heat medium circulates; and a controller configured to control the first and second flow switching devices such that in cooling and heating operations, the refrigerant and a heat-source-side fluid flow through the outdoor heat exchanger in opposite directions and the refrigerant flows through the relay heat exchanger in a constant direction. The pump is installed such that the heat medium, the refrigerant flow, and air for an air-conditioning target space flow in particular directions.

Abstract: An air-conditioning apparatus includes: a heat-source-side device that heats or cools a heat medium; a pump that sucks and transfers the heat medium; use-side heat exchangers; a heat medium circuit; flow rate control devices; indoor-side pressure sensors; a pump inlet-side pressure sensor and/or a pump outlet-side pressure sensor; a flow rate detection device that detects a pump flow rate; and a controller that performs a first operation in which the flow rate control devices are individually opened or closed and data regarding a flow passage resistance at a path related to each of the heat exchangers is obtained, and a second operation in which heat is supplied to indoor air, and calculates calculate flow rates of the heat medium that flows through the heat exchangers in the second operation, from pump flow rates and pressures detected by the pressure sensors in the first and second operations.

Abstract: A relay includes a first relay unit and a second relay unit provided between an outdoor unit and an indoor unit to allow refrigerant to circulate between the first relay unit and the outdoor unit and between the second relay unit and the outdoor unit, and a heat medium circuit connecting the first relay unit and the second relay unit to the indoor unit to allow a heat medium to circulate through the heat medium circuit. The second relay unit is installed above or on a top of the first relay unit.

Abstract: An air-conditioning apparatus includes outdoor units each including a compressor and outdoor heat exchanger, refrigerant flowing through the outdoor units; an indoor unit including an indoor heat exchanger, a heat medium flowing through the indoor unit; relay devices to which the outdoor units are connected, and to which the indoor unit is connected, each relay device includes a heat medium heat exchanger that exchanges heat between the refrigerant and the heat medium; and a controller. The controller controls action of the outdoor units, the indoor unit, and the relay devices. The controller determines necessity for a defrosting operation; responsive the defrosting operation being necessary, compares an indoor unit total load with an outdoor unit total capacity; and controls an operating frequency of the compressor of an outdoor unit other than the outdoor unit on which the defrosting operation is to be performed to increase the outdoor unit total capacity.

Abstract: An air conditioning apparatus includes: a second heat exchanger; a plurality of third heat exchangers; and a plurality of flow rate control valves. In a defrosting mode, when a heat exchanger that is not being requested to perform air conditioning includes a first device having a set temperature lower than or equal to a current room temperature and a second device which is set so as not to perform air conditioning, a controller is configured to control a first flow rate control valve corresponding to the first device and a second flow rate control valve corresponding to the second device such that a degree of opening of the first flow rate control valve is higher than or equal to a degree of opening of the second flow rate control valve.

Abstract: An air-conditioning apparatus includes: a heat medium circulation circuit including: a heat medium device, a heat medium pipe, a pump, a heat medium detection unit, and a controller that includes a count unit to count an air-conditioning operation time and count a pump operation time based on heat medium detection information of the heat medium detection unit, a storage unit storing a set air-conditioning time and a set pump time, a comparison unit to compare the air-conditioning operation time with the set air-conditioning time and compare the pump operation time with the set pump time, and a device control unit to control driving of the pump so that the pump operation time reaches or exceeds the set pump time when the air-conditioning operation time is longer than or equal to the set air-conditioning time and the pump operation time is shorter than the set pump time.

Abstract: An air-conditioning apparatus includes an outdoor unit, multiple indoor units, and an intermediate unit. The indoor units each include a flow control device and an indoor controller. The intermediate unit includes an intermediate heat exchanger, a circulation device, and an intermediate controller. When at least one indoor unit starts operating, the intermediate controller determines whether a flow rate of a heat medium flowing into the intermediate heat exchanger is greater than or equal to a minimum flow rate. In response to determining that the flow rate is less than the minimum flow rate, the intermediate controller transmits an open instruction signal, representing an instruction to increase the opening degree of the flow control device, to the indoor controller of the indoor unit that is in a non-operation state. The indoor controller increases the opening degree of the flow control device in response to the received open instruction signal.