Abstract: A hybrid multi-air conditioning system and a method for controlling a hybrid multi-air conditioning system are provided.

Abstract: An air conditioner and a method for controlling an air conditioner. The method may include detecting an outlet temperature of a compressor; detecting a change in temperature of a hot water supply pipe; determining a system error based on the outlet temperature of the compressor; and determining an abnormality in an adjustment valve based on the temperature of the hot water supply pipe when a system error is determined.

Abstract: An air conditioner includes an outdoor heat exchanger in which N heat exchange units are spaced apart from one another sequentially in a vertical direction N expansion valves respectively connected to the N heat exchange units; N hot gas pipes respectively connected to the N heat exchange units; N hot gas valves respectively installed in the N hot gas pipes; and a controller configured to control the N expansion valves and the N hot gas valves to defrost the N heat exchange units, wherein the controller is configured to defrost a bottom heat exchange unit first, then defrost a top heat exchange unit, and defrost the heat exchange units located under the top heat exchange unit sequentially from a second highest heat exchange unit to the bottom heat exchange unit after defrosting the top heat exchange unit.

Abstract: An air conditioner includes an outdoor heat exchanger in which N heat exchange units are spaced apart from one another sequentially in a vertical direction N expansion valves respectively connected to the N heat exchange units; N hot gas pipes respectively connected to the N heat exchange units; N hot gas valves respectively installed in the N hot gas pipes; and a controller configured to control the N expansion valves and the N hot gas valves to defrost the N heat exchange units, wherein the controller is configured to defrost a bottom heat exchange unit first, then defrost a top heat exchange unit, and defrost the heat exchange units located under the top heat exchange unit sequentially from a second highest heat exchange unit to the bottom heat exchange unit after defrosting the top heat exchange unit.

Abstract: A centrifugal blower for an air conditioner may include a centrifugal fan rotatably coupled to a motor, and a bell mouth guiding air into the centrifugal fan. The centrifugal fan may include a hub fixed to the motor, a main plate provided at an outer circumferential surface of the hub, a shroud surrounding the rotary shaft, the shroud positioned opposite the main plate to define a main gas flow path, and wings arranged along a circumferential direction of the suction opening between the main plate and the shroud. A rear axial end of the bell mouth may be inserted into the shroud through the suction opening so as to form a predetermined radial gap with the suction opening. A rear portion of the bell mouth may include alternately formed protrusions and recesses inserted into the shroud.

Abstract: Disclosed herein is a centrifugal fan. The centrifugal fan includes a back plate having a central portion for coupling with a rotation center shaft, a plurality of blades extending from the back plate, and a shroud which is connected to end portions of the blades and has an introduction end portion and a discharge end portion through which fluid passes, and the discharge end portion is rounded with a predetermined curvature in a direction away from the back plate.

Abstract: A network system equipped with an air conditioner and a control method may be provided. The network system may include: the air conditioner operating for air conditioning of a set space; a control device for updating set data in the air conditioner, and a control unit equipped in the air conditioner and for receiving update data from the control device. The control unit may include: an external memory for storing update data received from the control device, and an internal memory for selectively storing the update data stored in the external memory based on whether an update execute signal is received from the control device.

Abstract: A centrifugal blower for an air conditioner may include a centrifugal fan rotatably coupled to a motor, and a bell mouth guiding air into the centrifugal fan. The centrifugal fan may include a hub fixed to a rotary shaft of the motor, a main plate provided at an outer circumferential surface of the hub, a shroud having a suction opening surrounding the rotary shaft, the shroud positioned opposite the main plate to define a main gas flow path, and a plurality of wings arranged along the circumferential direction of the suction opening between the main plate and the shroud. A rear axial end portion of the bell mouth may be inserted into the shroud through the suction opening so as to form a predetermined radial gap with the suction opening. The rear portion of the bell mouth may include a plurality of alternately formed protruding portions and recessed portions, with the protruding portions and the recessed portions inserted into the shroud.

Abstract: A network system equipped with an air conditioner and a control method may be provided. The network system may include: the air conditioner operating for air conditioning of a set space; a control device for updating set data in the air conditioner, and a control unit equipped in the air conditioner and for receiving update data from the control device. The control unit may include: an external memory for storing update data received from the control device, and an internal memory for selectively storing the update data stored in the external memory based on whether an update execute signal is received from the control device.