# US 12,222,144 B2 · Variable capacity defrost > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,222,144 B2 - Document ID: US12222144B2 - Status: Granted - Kind: B2 - Application number: 17/865,002 - Filed: 2022-07-14 - Published: 2023-01-19 - Granted: 2025-02-11 - Earliest claimed: 2021-07-19 - Assignees: Carrier Corporation - Applicants: Carrier Corporation - Inventors: Charles A. Cluff - Web page: https://patentgrep.com/patent/US12222144B2 ## CPC - F25B 47/02: Defrosting cycles - F24F 11/41: Defrosting; Preventing freezing - F25B 49/02: for compression type machines, plants or systems - F25B 2600/01: Timing - F25B 2600/23: Time delays - F25B 2700/2103: near a heat exchanger - F25B 2700/2116: of a condenser - 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 A method of performing a defrost operation in a heating, ventilation and air conditioning (HVAC) system having a first heat exchanger and a second heat exchanger, the method including determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter; determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity. ## Claims ### Claim 1 A method of performing a defrost operation in a heating, ventilation and air conditioning (HVAC) system having a first heat exchanger and a second heat exchanger, wherein the defrost operation is performed on the second heat exchanger, the method comprising: determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter; determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity. ### Claim 2 (depends on 1) The method of claim 1, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that an increased capacity was used in one or more prior defrost operations. ### Claim 3 (depends on 1) The method of claim 1, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that one or more prior defrost operations was not completed within a defrost cycle time limit. ### Claim 4 (depends on 1) The method of claim 1, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that a rate of change of a temperature of the second heat exchanger was below a threshold in one or more prior defrost operations. ### Claim 5 (depends on 1) The method of claim 1, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that one or more prior defrost operations were completed in less than a defrost cycle time limit. ### Claim 6 (depends on 1) The method of claim 1, wherein the defrost parameter includes one or more of time elapsed since initiating the defrost operation, a temperature of the second heat exchanger, a rate of change of the temperature of the second heat exchanger and a time remaining until a defrost cycle time limit. ### Claim 7 (depends on 6) The method of claim 6, wherein increasing the capacity of the defrost operation includes increasing the capacity of the defrost operation when the temperature of the second heat exchanger has not reached a desired level within a predetermined time of the defrost cycle time limit. ### Claim 8 (depends on 6) The method of claim 6, wherein increasing the capacity of the defrost operation includes increasing the capacity of the defrost operation when the rate of change of the temperature of the second heat exchanger is less than a desired level. ### Claim 9 A heating, ventilation and air conditioning (HVAC) system comprising: a first heat exchanger; a second heat exchanger; a temperature sensor configured to sense a temperature of the second heat exchanger; a controller configured to execute defrost operations for the second heat exchanger including: determining that the defrost operation is needed; determining a capacity for the defrost operation in response to one or more prior defrost operations; beginning the defrost operation at the determined capacity; monitoring a defrost parameter, determining if the defrost parameter indicates a need for increased capacity; and increasing the capacity of the defrost operation when the defrost parameter indicates the need for increased capacity. ### Claim 10 (depends on 9) The HVAC system of claim 9, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that an increased capacity was used in one or more prior defrost operations. ### Claim 11 (depends on 9) The HVAC system of claim 9, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that one or more prior defrost operations was not complete within a defrost cycle time limit. ### Claim 12 (depends on 9) The HVAC system of claim 9, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that a rate of change of a temperature of the second heat exchanger was below a threshold in one or more prior defrost operations. ### Claim 13 (depends on 9) The HVAC system of claim 9, wherein determining the capacity for the defrost operation in response to one or more prior defrost operations includes determining that one or more prior defrost operations completed in less than a defrost cycle time limit. ### Claim 14 (depends on 9) The HVAC system of claim 9, wherein the defrost parameter includes one or more of time elapsed since initiating the defrost operation, a temperature of the second heat exchanger, a rate of change of the temperature of the second heat exchanger and a time remaining until a defrost cycle time limit. ### Claim 15 (depends on 14) The HVAC system of claim 14, wherein increasing the capacity of the defrost operation includes increasing the capacity of the defrost operation when the temperature of the second heat exchanger has not reached a desired level within a predetermined time of the defrost cycle time limit. ### Claim 16 (depends on 14) The HVAC system of claim 14, wherein increasing the capacity of the defrost operation includes increasing the capacity of the defrost operation when the rate of change of the temperature of the second heat exchanger is less than a desired level.