An air-conditioning apparatus includes an outdoor unit including an outdoor heat exchanger; an indoor unit including an indoor heat exchanger; and a relay unit provided between the outdoor unit and the indoor unit and including one or more first refrigerant supply pipes and one or more second refrigerant supply pipes that are connected to the indoor heat exchanger of the indoor unit. The one or more first refrigerant supply pipes and the one or more second refrigerant supply pipes protrude from the same side surface of the relay unit. The one or more first refrigerant supply pipes are each provided above an associated one of the one or more second refrigerant supply pipes. Part of the one or more first refrigerant supply pipes that protrudes from the side surface is longer than part of the one or more second refrigerant supply pipes that protrudes from the side surface.

A refrigerant distributor has a double-pipe structure including an inner pipe and an outer pipe. A plurality of outer pipes are disposed, each of the plurality of outer pipes being the outer pipe. A space is formed between adjacent ones of the plurality of outer pipes. The inner pipe is disposed to be continuous through the plurality of outer pipes. A plurality of heat-transfer tubes are arrayed in a direction in which the outer pipe extends and connected to the outer pipe. The refrigerant distributor distributes refrigerant flowing into between the inner pipe and the outer pipe to the plurality of heat-transfer tubes.

A refrigerant distributor has a double-pipe structure including an inner pipe and an outer pipe. A plurality of outer pipes are disposed, each of the plurality of outer pipes being the outer pipe. A space is formed between adjacent ones of the plurality of outer pipes. The inner pipe is disposed to be continuous through the plurality of outer pipes. A plurality of heat-transfer tubes are arrayed in a direction in which the outer pipe extends and connected to the outer pipe. The refrigerant distributor distributes refrigerant flowing into between the inner pipe and the outer pipe to the plurality of heat-transfer tubes.

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.

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.

An indoor unit of an air-conditioning apparatus includes a housing defining an outer shape of the indoor unit, and a pipe hole-opening groove section that is in a form of grid-like grooves on an inner surface of the housing. The housing has a box-like shape and includes a lower one surface panel forming a lower end of one side surface of the housing, a one end bottom panel forming one end of a bottom surface of the housing, a lower other surface panel forming a lower end of the other side surface of the housing, and the other end bottom panel forming the other end of the bottom surface of the housing. The pipe hole-opening groove section is formed in at least one of the lower one surface panel, the one end bottom panel, the lower other surface panel, and the other end bottom panel.

A tube guide for a heating, ventilation, and/or air conditioning (HVAC) system includes a main body formed from a pliable material, a first slit formed through the main body, and a second slit formed through the main body and traversing the first slit to define a tube support location configured to receive a range of tube sizes.

A heat exchanger has first and second heat exchange units disposed one above the other. In a case where the heat exchanger functions as a condenser, refrigerant flows through the second heat exchange unit after having flowed through the first heat exchange unit. An intermediate header unit through which the first heat exchange unit and the second heat exchange unit communicate with each other causes at least a portion of refrigerant having flowed through a first heat transfer pipe group on the windward side of the first heat exchange unit to flow to a fourth heat transfer pipe group. Further, the intermediate header unit causes at least a portion of refrigerant having flowed through a second heat transfer pipe group on the leeward side of the first heat exchange unit to flow into a third heat transfer pipe group or the fourth heat transfer pipe group.

A heat exchanger has first and second heat exchange units disposed one above the other. In a case where the heat exchanger functions as a condenser, refrigerant flows through the second heat exchange unit after having flowed through the first heat exchange unit. An intermediate header unit through which the first heat exchange unit and the second heat exchange unit communicate with each other causes at least a portion of refrigerant having flowed through a first heat transfer pipe group on the windward side of the first heat exchange unit to flow to a fourth heat transfer pipe group. Further, the intermediate header unit causes at least a portion of refrigerant having flowed through a second heat transfer pipe group on the leeward side of the first heat exchange unit to flow into a third heat transfer pipe group or the fourth heat transfer pipe group.

In an air-conditioning system including a thermal storage heat exchanger, a refrigerant circuit is configured such that an indoor heat exchanger and a receiver communicate with the thermal storage heat exchanger when an operational mode of the refrigerant circuit is switched to a cooling operation in which the thermal storage heat exchanger serves as a radiator and the indoor heat exchanger serves as an evaporator.