# US 2019/0170385 A1 · Systems and methods for detecting and responding to refrigerant leaks in heating, ventilating, and air conditioning systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170385 A1 - Document ID: US20190170385A1 - Status: Published application - Kind: A1 - Application number: 15/874,630 - Filed: 2018-01-18 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Johnson Controls Technology Company - Applicants: Johnson Controls Technology Company - Inventors: Steven M. Maddox; William F. McQuade - Web page: https://patentgrep.com/patent/US20190170385A1 ## CPC - F24F 11/36: to leakage of heat-exchange fluid - F24F 1/0035: characterised by introduction of outside air to the room - F24F 1/0041: characterised by exhaustion of inside air from the room (in combination with simultaneous introduction of outside air F24F1/0038) - F24F 1/022: comprising a compressor cycle - F24F 7/007: with forced flow (using ducting systems F24F7/06) - F24F 11/70: Control systems characterised by their outputs; Constructional details thereof - F24F 11/72: for controlling the supply of treated air, e.g. its pressure - F24F 11/89: Arrangement or mounting of control or safety devices - F24F 2110/65: Concentration of specific substances or contaminants - Y02B 30/70: Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating - 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) - Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS ## Abstract The present disclosure relates to a heating, ventilating, and air conditioning (HVAC) system that includes a refrigerant circuit and a sensor configured to measure a refrigerant concentration external to the refrigeration circuit. The HVAC system also includes a controller that is communicatively coupled to the sensor and to an economizer. The controller is configured to control a flow of environmental air into the HVAC system. The controller is further configured to increase a ratio of the flow of environmental air relative to a flow of return air from a conditioned interior space of a building when the sensor measures the refrigerant concentration above a predetermined threshold concentration. ## Claims ### Claim 1 A heating, ventilating, and air conditioning (HVAC) system, comprising: a refrigerant circuit; a sensor configured to measure a refrigerant concentration external to the refrigeration circuit; and a controller communicatively coupled to the sensor and to an economizer that is configured to control a flow of environmental air into the HVAC system, wherein the controller is configured to increase a ratio of the flow of environmental air relative to a flow of return air from a conditioned interior space of a building when the sensor measures the refrigerant concentration above a predetermined threshold concentration. ### Claim 2 (depends on 1) The HVAC system of claim 1, wherein the controller is configured to adjust the economizer to a particular position to increase the ratio of the flow of environmental air relative to the flow of return air based on the measured refrigerant concentration. ### Claim 3 (depends on 2) The HVAC system of claim 2, wherein the particular position of the economizer is a maximum open position that substantially maximizes the flow of environmental air into the HVAC system. ### Claim 4 (depends on 1) The HVAC system of claim 1, comprising an exhaust air damper communicatively coupled to the controller, wherein the exhaust air damper is configured to control a flow of conditioned air from the conditioned interior space of the building to an external environment, and wherein the controller is configured to adjust the exhaust air damper to a particular position to increase the ratio of the flow of environmental air relative to the flow of return air based on the measured refrigerant concentration. ### Claim 5 (depends on 4) The HVAC system of claim 4, wherein the particular position of the exhaust air damper is a maximum open position that substantially maximizes the flow of conditioned air from the conditioned interior space of the building to the external environment. ### Claim 6 (depends on 4) The HVAC system of claim 4, comprising a return air damper communicatively coupled to the controller, wherein the return air damper is configured to control the flow of return air into a HVAC unit of the HVAC system, and the controller is configured to adjust the return air damper to a second particular position to increase the ratio of the flow of environmental air relative to the flow of return air based on the measured refrigerant concentration. ### Claim 7 (depends on 6) The HVAC system of claim 6, wherein the second particular position of the return air damper is a maximum closed position that substantially prevents the flow of return air into the HVAC unit. ### Claim 8 (depends on 1) The HVAC system of claim 1, wherein the sensor is disposed within an interior of a HVAC unit of the HVAC system. ### Claim 9 (depends on 8) The HVAC system of claim 8, wherein the sensor is disposed near an evaporator or a condenser of the HVAC unit, and wherein the sensor is configured to measure the refrigerant concentration within the interior of the HVAC unit when a supply fan of the HVAC unit is deactivated. ### Claim 10 (depends on 1) The HVAC system of claim 1, wherein the sensor is disposed in ductwork of the HVAC system. ### Claim 11 (depends on 1) The HVAC system of claim 1, wherein, after increasing the ratio of the flow of environmental air relative to the flow of return air, the controller is configured to further increase the ratio of the flow of environmental air to the flow of return air when the sensor measures a second refrigerant concentration that is greater than the predetermined threshold concentration. ### Claim 12 (depends on 1) The HVAC system of claim 1, wherein the controller is communicatively coupled to a second sensor that is configured to measure a second refrigerant concentration, and wherein the controller is configured to increase the ratio of the flow of environmental air to the flow of return air when the second sensor measures the second refrigerant concentration above the predetermined threshold concentration. ### Claim 13 (depends on 1) The HVAC system of claim 1, comprising a HVAC unit that includes the economizer, wherein the economizer is configured to control the flow of environmental air into the HVAC unit of the HVAC system. ### Claim 14 (depends on 1) The HVAC system of claim 1, wherein the economizer is disposed outside of a HVAC unit of the HVAC system and fluidly coupled to the HVAC unit via ductwork of the HVAC system. ### Claim 15 A heating, ventilating, and air conditioning (HVAC) system comprising: an economizer configured to control a flow of environmental air into the HVAC system; a sensor configured to measure a leaked refrigerant concentration within the HVAC system; and a controller communicatively coupled to the sensor and the economizer, wherein the controller is configured to increase a ratio of the flow of environmental air relative to a flow of return air from a conditioned interior space of a building when the sensor measures the leaked refrigerant concentration above a predetermined threshold concentration. ### Claim 16 (depends on 15) The HVAC system of claim 15, comprising a HVAC unit that includes the economizer. ### Claim 17 (depends on 16) The HVAC system of claim 16, comprising a second HVAC unit, wherein the second HVAC unit comprises: a second economizer configured to control a second flow of environmental air into the second HVAC unit; a second sensor configured to measure a second leaked refrigerant concentration near the second HVAC unit; a second controller communicatively coupled to the second sensor and the second economizer, wherein the second controller is configured to increase a second ratio of the second flow of environmental air relative to a second flow of return air from the conditioned interior space of the building when the second sensor measures the second leaked refrigerant concentration above the predetermined threshold concentration. ### Claim 18 (depends on 17) The HVAC system of claim 17, wherein the controller of the HVAC unit and the second controller of the second HVAC unit are communicatively coupled, wherein the controller is configured to increase the second ratio of the second flow of environmental air relative to the second flow of return air when the sensor measures the leaked refrigerant concentration above the predetermined threshold concentration. ### Claim 19 (depends on 15) The HVAC system of claim 15, comprising a second HVAC unit, wherein the second HVAC unit comprises: a second sensor configured to measure a second leaked refrigerant concentration near the second HVAC unit; a second controller communicatively coupled to the second sensor and the controller, wherein the controller is configured to increase the ratio of the flow of environmental air relative to the flow of return air when the second sensor measures the second leaked refrigerant concentration above the predetermined threshold concentration. ### Claim 20 (depends on 19) The HVAC system of claim 19, wherein the second unit does not include a respective economizer. ### Claim 21 (depends on 19) The HVAC system of claim 19, wherein the sensor is disposed within ductwork of the conditioned interior space. ### Claim 22 (depends on 15) The HVAC system of claim 15, wherein the sensor is disposed upstream of supply ductwork of the HVAC system and is configured to measure the leaked refrigerant concentration in conditioned air before the conditioned air enters the supply ductwork of the HVAC system. ### Claim 23 (depends on 15) The HVAC system of claim 15, wherein the HVAC system comprises an alarm and the controller is configured to activate the alarm when the sensor measures the leaked refrigerant concentration above the predetermined threshold concentration. ### Claim 24 (depends on 15) The HVAC system of claim 15, wherein the controller is configured to send a notification to an electronic device when the sensor measures the leaked refrigerant concentration above the predetermined threshold concentration. ### Claim 25 A method of controlling a packaged heating, ventilating, and air conditioning (HVAC) system comprising an economizer that controls a flow of environmental air into the HVAC system, wherein the method comprises: measuring a concentration of leaked refrigerant near a packaged HVAC unit of the HVAC system or within ductwork of the HVAC system; and in response to determining that the measured concentration of leaked refrigerant is above a predetermined threshold value, adjusting the economizer to increase a ratio of the flow of environmental air to a flow of return air supplied by the HVAC system. ### Claim 26 (depends on 25) The method of claim 25, comprising: after adjusting the economizer, measuring a second concentration of leaked refrigerant near the packaged HVAC unit or within the ductwork of the HVAC system; and in response to determining that the measured second concentration of leaked refrigerant concentration is above the measured concentration of leaked refrigerant or that the second concentration of leaked refrigerant is above the predetermined threshold value, adjusting the economizer to further increase the ratio of the flow of environmental air to the flow of return air supplied by the HVAC system. ### Claim 27 (depends on 25) The method of claim 25, wherein adjusting the economizer comprises increasing the flow of environmental air directly into the packaged HVAC unit to increase the ratio of the flow of environmental air to the flow of return air supplied by the HVAC system. ### Claim 28 (depends on 25) The method of claim 25, wherein adjusting the economizer comprises increasing the flow of environmental air directly into another packaged HVAC unit of the HVAC system to increase the ratio of the flow of environmental air to the flow of return air supplied by the HVAC system. ### Claim 29 (depends on 25) The method of claim 25, wherein adjusting the economizer comprises increasing the flow of environmental air into a different portion of the HVAC system than the packaged HVAC unit to increase the ratio of the flow of environmental air to the flow of return air supplied by the HVAC system. ### Claim 30 (depends on 25) The method of claim 25, comprising, in response to determining that the measured concentration of leaked refrigerant is greater than the predetermined threshold value, adjusting an exhaust air damper or return air damper of the packaged HVAC unit to increase the ratio of the flow of environmental air to the flow of return air supplied by the HVAC system.