# US 2024/0200843 A1 · Air-conditioning apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2024/0200843 A1 - Document ID: US20240200843A1 - Status: Published application - Kind: A1 - Application number: 18/555,984 - Filed: 2021-07-07 - Published: 2024-06-20 - Earliest claimed: 2021-07-07 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Nobuhiro WADA - Web page: https://patentgrep.com/patent/US20240200843A1 ## CPC - F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) - F25B 49/02: for compression type machines, plants or systems - F24F 11/36: to leakage of heat-exchange fluid - F25B 41/20: Disposition of valves, e.g. of on-off valves or flow control valves (expansion valves F25B41/31) - F25B 49/005: {of safety devices (F25B49/02 and F25B49/04 take precedence)} - F25B 2313/0233: in parallel arrangements - F25B 2313/0314: Temperature sensors near the indoor heat exchanger - F25B 2400/0409: for evaporators - F25B 2400/0411: for expansion valves or capillary tubes - F25B 2500/221: Preventing leaks from developing - F25B 2500/222: Detecting refrigerant leaks - F25B 2500/28: Means for preventing liquid refrigerant entering into the compressor - F25B 2600/0253: with variable speed - F25B 2600/2501: Bypass valves - F25B 2600/2509: Economiser valves - F25B 2600/2519: On-off valves - F25B 2700/1931: Discharge pressures - F25B 2700/1933: Suction pressures - F25B 2700/2104: of an indoor room or compartment - F25B 2700/21174: of the refrigerant at the inlet of the evaporator - F25B 2700/21175: of the refrigerant at the outlet of the evaporator - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - F24F: AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING (removing dirt or fumes from areas where they are produced B08B15/00; vertical ducts for carrying away waste gases from buildings E04F17/02; tops for chimneys or ventilating shafts, terminals for flues F23L17/02) ## Abstract An air-conditioning apparatus includes a refrigerant circuit including a compressor, a heat-source-side heat exchanger, an expansion device, a load-side heat exchanger, and a shut-off valve connected in sequence by pipes to allow refrigerant to flow therethrough; a heat-source-side air-sending device configured to send air to the heat-source-side heat exchanger; a leakage detecting unit configured to detect refrigerant leakage; and a controller configured to perform cooling operation. The controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, close the shut-off valve after lowering an operation frequency of the compressor and increasing a rotation speed of the heat-source-side air-sending device. ## Claims ### Claim 1 An air-conditioning apparatus comprising: a refrigerant circuit including a compressor, a heat-source-side heat exchanger, an expansion device, a load-side heat exchanger, and a shut-off valve connected in sequence by pipes to allow refrigerant to flow therethrough; a heat-source-side air-sending device configured to send air to the heat-source-side heat exchanger; a leakage detecting unit configured to detect refrigerant leakage; and a controller configured to perform cooling operation, wherein the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, close the shut-off valve after lowering an operation frequency of the compressor and increasing a rotation speed of the heat-source-side air-sending device. ### Claim 2 An air-conditioning apparatus comprising: a refrigerant circuit including a compressor, a heat-source-side heat exchanger, an expansion device, a heat medium heat exchanger, and a shut-off valve connected in sequence by pipes to allow refrigerant to flow therethrough; a heat medium circuit including a pump, the heat medium heat exchanger, a heat medium flow control device, and a load-side heat exchanger connected in sequence by pipes to allow a heat medium to flow therethrough; a heat-source-side air-sending device configured to send air to the heat-source-side heat exchanger; a leakage detecting unit configured to detect refrigerant leakage; and a controller configured to perform cooling operation, wherein the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, close the shut-off valve after lowering an operation frequency of the compressor and increasing a rotation speed of the heat-source-side air-sending device. ### Claim 3 (depends on 1) The air-conditioning apparatus of claim 1, wherein the refrigerant circuit includes a flow switching device configured to switch a direction of flow of the refrigerant between cooling operation and heating operation; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during heating operation, close the shut-off valve after lowering the operation frequency of the compressor and decreasing the rotation speed of the heat-source-side air-sending device. ### Claim 4 (depends on 1) The air-conditioning apparatus of claim 1, comprising a load-side air-sending device configured to send air to the load-side heat exchanger, wherein the controller is configured to, if the leakage detecting unit detects refrigerant leakage during heating operation, increase the rotation speed of the load-side air-sending device before closing the shut-off valve. ### Claim 5 (depends on 1) The air-conditioning apparatus of claim 1, wherein the refrigerant circuit includes a heat-source-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and a suction side of the compressor in cooling operation, and a heat-source-side bypass opening and closing device disposed in the heat-source-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-source-side bypass opening and closing device before closing the shut-off valve. ### Claim 6 (depends on 2) The air-conditioning apparatus of claim 2, wherein the refrigerant circuit includes a heat-medium-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and the heat medium heat exchanger, and a heat-medium-side bypass opening and closing device disposed in the heat-medium-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-medium-side bypass opening and closing device before closing the shut-off valve. ### Claim 7 (depends on 2) The air-conditioning apparatus of claim 2, wherein the refrigerant circuit includes a flow switching device configured to switch a direction of flow of the refrigerant between cooling operation and heating operation; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during heating operation, close the shut-off valve after lowering the operation frequency of the compressor and decreasing the rotation speed of the heat-source-side air-sending device. ### Claim 8 (depends on 2) The air-conditioning apparatus of claim 2, comprising a load-side air-sending device configured to send air to the load-side heat exchanger, wherein the controller is configured to, if the leakage detecting unit detects refrigerant leakage during heating operation, increase the rotation speed of the load-side air-sending device before closing the shut-off valve. ### Claim 9 (depends on 3) The air-conditioning apparatus of claim 3, comprising a load-side air-sending device configured to send air to the load-side heat exchanger, wherein the controller is configured to, if the leakage detecting unit detects refrigerant leakage during heating operation, increase the rotation speed of the load-side air-sending device before closing the shut-off valve. ### Claim 10 (depends on 2) The air-conditioning apparatus of claim 2, wherein the refrigerant circuit includes a heat-source-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and a suction side of the compressor in cooling operation, and a heat-source-side bypass opening and closing device disposed in the heat-source-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-source-side bypass opening and closing device before closing the shut-off valve. ### Claim 11 (depends on 3) The air-conditioning apparatus of claim 3, wherein the refrigerant circuit includes a heat-source-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and a suction side of the compressor in cooling operation, and a heat-source-side bypass opening and closing device disposed in the heat-source-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-source-side bypass opening and closing device before closing the shut-off valve. ### Claim 12 (depends on 4) The air-conditioning apparatus of claim 4, wherein the refrigerant circuit includes a heat-source-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and a suction side of the compressor in cooling operation, and a heat-source-side bypass opening and closing device disposed in the heat-source-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-source-side bypass opening and closing device before closing the shut-off valve. ### Claim 13 (depends on 7) The air-conditioning apparatus of claim 7, wherein the refrigerant circuit includes a heat-medium-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and the heat medium heat exchanger, and a heat-medium-side bypass opening and closing device disposed in the heat-medium-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-medium-side bypass opening and closing device before closing the shut-off valve. ### Claim 14 (depends on 8) The air-conditioning apparatus of claim 8, wherein the refrigerant circuit includes a heat-medium-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and the heat medium heat exchanger, and a heat-medium-side bypass opening and closing device disposed in the heat-medium-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-medium-side bypass opening and closing device before closing the shut-off valve. ### Claim 15 (depends on 10) The air-conditioning apparatus of claim 10, wherein the refrigerant circuit includes a heat-medium-side bypass pipe branching off from a passage between the heat-source-side heat exchanger and the expansion device and joining a passage between the shut-off valve and the heat medium heat exchanger, and a heat-medium-side bypass opening and closing device disposed in the heat-medium-side bypass pipe; and the controller is configured to, if the leakage detecting unit detects refrigerant leakage during cooling operation, open the heat-medium-side bypass opening and closing device before closing the shut-off valve.