# US 12,111,068 B2 · Refrigeration cycle apparatus > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,068 B2 - Document ID: US12111068B2 - Status: Granted - Kind: B2 - Application number: 18/207,598 - Filed: 2023-06-08 - Published: 2023-10-05 - Granted: 2024-10-08 - Earliest claimed: 2021-01-29 - Assignees: Daikin Industries, Ltd. - Applicants: Daikin Industries, Ltd. - Inventors: Akihiro Nakano; Ken Takahashi - Web page: https://patentgrep.com/patent/US12111068B2 ## CPC - F24F 1/14: Heat exchangers specially adapted for separate outdoor units - F24F 11/84: using valves - F24F 1/26: Refrigerant piping - F24F 1/30: for use inside the separate outdoor units - F24F 11/83: by controlling the supply of heat-exchange fluids to heat-exchangers - F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) - F25B 39/04: Condensers - F25B 41/37: Capillary tubes - F25B 41/42: Arrangements for diverging or converging flows, e.g. branch lines or junctions - F25B 49/02: for compression type machines, plants or systems - F24F 2140/20: Heat-exchange fluid temperature - F24F 2140/50: Load - F25B 2600/2503: Condenser exit valves - 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) - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract The disclosure prevents a state where a liquid refrigerant is likely to be accumulated in an outdoor heat exchanger upon small load operation at low outdoor temperature during cooling operation. A junction part is disposed between a path and a liquid side inlet-outlet port, and includes a junction flow passage configured to cause a refrigerant flowing from the path to the liquid side inlet-outlet port to join and flow therein. A branching passage has a first end connected to the path, and a second end connected to the junction flow passage. An outdoor heat exchanger is configured to increase, upon decrease in load, a flow rate ratio of a refrigerant flowing to the branching passage to volume of a refrigerant flowing to the path. ## Claims ### Claim 1 A refrigeration cycle apparatus comprising a refrigerant circuit including an outdoor heat exchanger configured to cause heat exchange between outdoor air and a refrigerant, and a controller configured to control an operating frequency of a compressor configured to discharge a compressed refrigerant, the refrigerant circuit configured to achieve a vapor compression refrigeration cycle while the outdoor heat exchanger functions as a condenser, wherein the outdoor heat exchanger includes an inlet port where a refrigerant flows into the outdoor heat exchanger when the outdoor heat exchanger functions as a condenser, an outlet port where a refrigerant flows out the outdoor heat exchanger when the outdoor heat exchanger functions as a condenser, a plurality of heat exchange paths including a plurality of heat transfer tubes configured to cause the refrigerant flowing in through the inlet port upon the heat exchange to be distributed and flow in parallel, a junction flow passage disposed between the plurality of heat exchange paths and the outlet port and configured to cause refrigerant flowing from the plurality of heat exchange paths to the outlet port to join and then flow therein, and a branching passage, the plurality of heat exchange paths includes a first path disposed in a lower portion of the outdoor heat exchanger, and a second path disposed above the first path, the junction flow passage is configured to cause refrigerant having passed at least the first path and the second path to join and then flow therein, the branching passage includes a capillary tube, and has a first end connected to the first path and a second end connected to the junction flow passage, the first end of the branching passage is connected to a portion on the outlet port side of the heat transfer tube in the first path, the plurality of heat transfer tubes of the plurality of heat exchange paths penetrates through a corresponding plurality of heat transfer fins, and the controller, in response to a decrease in load of the air conditioning apparatus, is configured to increase a flow rate ratio of the refrigerant flowing to the branching passage to volume of the refrigerant flowing to the first path at the outdoor heat exchanger, by using the capillary tube and by controlling the operating frequency of the compressor. ### Claim 2 (depends on 1) The refrigeration cycle apparatus according to claim 1, wherein the flow rate ratio of volume of the refrigerant flowing to the branching passage to volume of the refrigerant flowing from the first path without passing the branching passage during predetermined small load operation is five times or more in comparison to the flow rate ratio during rated operation. ### Claim 3 (depends on 1) The refrigeration cycle apparatus according to claim 1, wherein the refrigerant flowing to the refrigerant circuit is an R32 refrigerant, and a ratio of pressure loss from the first end to the second end of the branching passage to pressure loss from the first path to the second end via the junction flow passage is less than one during predetermined small load operation. ### Claim 4 (depends on 2) The refrigeration cycle apparatus according to claim 2, wherein the refrigerant flowing to the refrigerant circuit is an R32 refrigerant, and a ratio of pressure loss from the first end to the second end of the branching passage to pressure loss from the first path to the second end via the junction flow passage is less than one during predetermined small load operation.