# US 11,441,827 B2 · Refrigerant leak detection system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,441,827 B2 - Document ID: US11441827B2 - Status: Granted - Kind: B2 - Application number: 17/003,087 - Filed: 2018-02-27 - Published: 2021-07-01 - Granted: 2022-09-13 - Earliest claimed: 2018-02-27 - Assignees: Carrier Corporation - Applicants: Carrier Corporation; Michel Grabon - Inventors: Michel Grabon - Web page: https://patentgrep.com/patent/US11441827B2 ## CPC - F25B 49/02: for compression type machines, plants or systems - F25B 2500/19: Calculation of parameters - F25B 2500/222: Detecting refrigerant leaks - F25B 2600/01: Timing - F25B 2600/0253: with variable speed - F25B 2600/2513: Expansion valves - F25B 2700/195: of the condenser - F25B 2700/197: of the evaporator - Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract Disclosed is a system for detecting a refrigerant leak in a refrigeration system, wherein a system controller is configured to: execute leak test cycles that include executing a first phase (T1-T2) of transferring refrigerant charge to the evaporator, a second phase (T2-T3) of transferring refrigerant charge to the condenser, and a third phase (T3-T4) of transferring refrigerant charge to the evaporator, determine a reference leak detection cycle time (LDCTREF) by determining a time from a beginning of the second phase (T2) in a first test to an end of the third phase (T4) in the first test, and setting LDCTREF to the time, determine a second leak detection cycle time (LDCT2nd) by determining a time from a beginning of the second phase (T2) in the second test to a second end of the third phase (T4) in the second test, and setting LDCT2nd to the time, determine if a refrigerant leak exists, and communicate the determination. ## Claims ### Claim 1 A refrigeration system for detecting a refrigerant leak, the refrigeration system including a refrigerant charge, an evaporator, a condenser and a system controller, wherein the controller is configured to: execute a plurality of leak test cycles, including a first leak test cycle and a second leak test cycle, each of the plurality of leak test cycles comprising executing a first phase of transferring the refrigerant charge to the evaporator, executing a second phase of transferring the refrigerant charge to the condenser, and executing a third phase of transferring the refrigerant charge to the evaporator, determine a reference leak detection cycle time by determining a first time from a first beginning of the second phase in the first leak test cycle to a first end of the third phase in the first leak test cycle, and setting the reference leak detection cycle time to the first time, determine a second leak detection cycle time by determining a second time from a second beginning of the second phase in the second leak test cycle to a second end of the third phase in the second leak test cycle, and setting the second leak detection cycle time to the second time, determine that a refrigerant leak in the refrigeration system exists because the second leak detection cycle time is shorter in duration than the reference leak detection cycle time, and communicate an existence of the refrigerant leak with an alert which is one or more of visual, audible, and vibratory. ### Claim 2 (depends on 1) The system of claim 1, wherein the first phase initiates with the controller taking the refrigeration system off line. ### Claim 3 (depends on 1) The system of claim 1, wherein the third phase concludes with the control bringing the refrigeration system on line. ### Claim 4 (depends on 1) The system according to claim 1, wherein the controller periodically performs one of the first leak detection test cycle and the second leak detection test cycles. ### Claim 5 (depends on 1) The system according to claim 1, wherein the controller performs the one of the first leak detection test cycle and the second leak detection test cycles following a non-periodic trigger event. ### Claim 6 (depends on 5) The system of claim 5 wherein the trigger event includes the controller bringing the refrigeration system off line for maintenance. ### Claim 7 (depends on 3) The system according to claim 3, wherein the refrigeration system includes a variable speed compressor and an electronic expansion valve, and wherein the first phase starts at a time T1 and ends at a time T2 as monitored by the controller, and throughout the first phase the controller sets the compressor to minimum output and the electronic expansion valve to maximum opened, and the controller monitors pressure in at least one of the condenser and evaporator to determine when the evaporator is charged with a maximum amount of the system refrigerant that is available in the refrigerant system and the condenser is empty of the system refrigerant. ### Claim 8 (depends on 7) The system of claim 7, wherein the second phase starts at the time T2 and ends at a time T3 as monitored by the controller, and throughout the second phase the controller sets the compressor to minimum output and sets the electronic expansion valve to closed, and the controller monitors pressure in at least one of the condenser and evaporator to determine when the condenser is charged with the maximum amount of the system refrigerant that is available in the refrigerant system and the evaporator is empty of the system refrigerant. ### Claim 9 (depends on 8) The system of claim 8, wherein the third phase starts at the time T3 and ends at a time T4 as monitored by the controller, and throughout the third phase the controller sets the compressor to no output and sets the electronic expansion valve to maximum opened, and the controller monitors pressure in at least one of the condenser and evaporator to determine when the evaporator is charged with the system refrigerant and the compressor is empty of system refrigerant. ### Claim 10 (depends on 9) The system according to claim 9, wherein the controller monitors evaporator suction pressure to determine when the evaporator is empty of system refrigerant.