Mitsubishi Electric Corporation

Akinori Sakabe

Naoki Nakagawa

Kosuke Tanaka

Masanori Sato

Hiroaki Makino

Yusuke Tashiro

Masayuki Oishi

Hiroyuki Jinnai

Toshiyuki Kubono

Hidetomo Nakagawa

Seiji Hirakawa

Masakazu Kondo

Tadashi Ariyama

Atsushi Kawashima

Yasuhide Hayamaru

Komei Nakajima

Ryosuke Matsui

An air-conditioning apparatus includes a load-side heat exchanger including a first heat exchanger disposed on a windward of a second heat exchanger in a direction of an air flow generated by an air-sending device. The air flow passing through the first heat exchanger passes through a second heat exchanger. During cooling operation, a bypass valve causes a part of refrigerant flowing through a first refrigerant pipe to flow through a coupling pipe through a bypass pipe. During heating operation, the bypass valve blocks a flow of the refrigerant flowing from the coupling pipe toward the first refrigerant pipe through the bypass pipe, and causes all of the refrigerant flowing through the coupling pipe to flow from the coupling pipe to the first heat exchanger.

Air-conditioning apparatus

An air-conditioning apparatus includes a first flow switching unit configured to be switched between a first state in which refrigerant communication between a compressor and a second load-side heat exchanger is blocked and a second state in which the compressor is in refrigerant communication with a first load-side heat exchanger and the second load-side heat exchanger. The air-conditioning apparatus further includes a second flow switching unit configured to be switched between a third state in which refrigerant communication between the second load-side heat exchanger and a heat-source-side heat exchanger is blocked and a fourth state in which the first load-side heat exchanger is in refrigerant communication with the second load-side heat exchanger and the heat-source-side heat exchanger. The first heat exchanger is located upstream of the second load-side heat exchanger. The second flow switching unit is located downstream of the second load-side heat exchanger.

Air-conditioning apparatus provided with refrigerant circuit capable of performing heating operation

An air-conditioning apparatus including a compressor incorporating an electric motor; a temperature sensor configured to detect indoor temperature; a drive circuit configured to drive the electric motor; a connection switching device configured to switch connection of stator windings of the electric motor between a first connection state and a second connection state higher in line-to-line voltage than the first connection state; and a controller configured to enter thermo-off when the indoor temperature reaches a target temperature or a correction temperature set based on the target temperature and cause the connection switching device to switch connection, the thermo-off being entered by stopping the compressor via the drive circuit. When a thermo-off count reaches a reference count with the electric motor being in the first connection state, the controller causes the connection switching device to switch connection from the first connection state to the second connection state.

Air-conditioning apparatus having a compressor-motor-connection switcher

An air-conditioning apparatus includes a refrigerant circuit including a compressor, an indoor-side heat exchanger, and an outdoor-side heat exchanger; a drive circuit configured to drive an electric motor; a connection switching device configured to switch connection of stator windings of the electric motor between a first connection state and a second connection state higher in line-to-line voltage than the first connection state; and a controller configured to perform defrosting operation for removing frost formed on the outdoor-side heat exchanger and cause the connection switching device to switch connection. In performing the defrosting operation with the stator windings being in the second connection state, the controller causes the connection switching device to switch the connection of the stator windings from the second connection state to the first connection state.

Air-conditioning apparatus with switched connection states of windings of compressor motor prior to defrost operation

An air-conditioning apparatus includes a time constant calculation unit that estimates a response time constant at a time when an opening degree of an expansion device is changed on the basis of specifications of a compressor that forms a refrigeration cycle of the air-conditioning apparatus, specifications of a load side heat exchanger, and an operating state quantity of the air-conditioning apparatus, a control constant calculation means that calculates at least one of a control gain of the opening degree of the expansion device and a control interval on the basis of a calculation result of the time constant calculation means, and a control constant change means that changes a control constant.

Growing community of inventors

Tokyo, Japan

Akinori Sakabe