# US 2019/0170604 A1 · Systems and methods for refrigerant leak management > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170604 A1 - Document ID: US20190170604A1 - Status: Published application - Kind: A1 - Application number: 15/871,698 - Filed: 2018-01-15 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Johnson Controls Technology Company - Applicants: Johnson Controls Technology Company - Inventors: Douglas A. Kester - Web page: https://patentgrep.com/patent/US20190170604A1 ## CPC - G01M 3/2807: {for pipes (G01M3/2892, G01M3/30 take precedence)} - F24F 11/36: to leakage of heat-exchange fluid - F25B 49/005: {of safety devices (F25B49/02 and F25B49/04 take precedence)} - G01M 3/226: {for containers, e.g. radiators} - G01M 3/40: by using electric means, e.g. by observing electric discharges - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - 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 A refrigerant leak management system of a HVAC unit includes a sensor configured to detect a refrigerant in an interior of an air handling enclosure. The refrigerant leak management system includes a plurality of airflow management assemblies configured to fluidly isolate the interior of the air handling enclosure in a closed configuration. The plurality of airflow management assemblies includes a return inlet assembly, a supply outlet assembly, and a purge exhaust outlet assembly. The refrigerant leak management system includes a controller configured to actuate the purge exhaust outlet assembly based on detection of the refrigerant by the sensor such that the purge exhaust outlet assembly transitions from a closed position of the purge exhaust outlet assembly to an open position of the purge exhaust outlet assembly that opens the interior of the air handling enclosure to an external environment. ## Claims ### Claim 1 A refrigerant leak management system of a heating, ventilation, and air conditioning (HVAC) unit comprising: an air handler having a return inlet, a supply outlet, and a purge exhaust, the purge exhaust routing from an interior of the air handler to an external environment and being normally closed; a sensor configured to detect a refrigerant in the interior of the air handler; and a controller configured to: operate in a first mode to close the return inlet, the supply outlet, and the purge exhaust to facilitate detection of the refrigerant by the sensor; and operate in a second mode, based on detection of the refrigerant, to open the purge exhaust to route the refrigerant from the interior of the air handler to the external environment. ### Claim 2 (depends on 1) The refrigerant leak management system of claim 1, wherein the controller is configured such that the return inlet and the supply outlet are each normally open. ### Claim 3 (depends on 1) The refrigerant leak management system of claim 1, wherein the purge exhaust substantially blocks flow therethrough while the purge exhaust is closed. ### Claim 4 (depends on 1) The refrigerant leak management system of claim 1, wherein the controller is configured such that the supply outlet is closed during the second mode. ### Claim 5 (depends on 1) The refrigerant leak management system of claim 1, wherein the controller is configured to have a third mode in which the return inlet and the supply outlet are open and the purge exhaust is closed while the HVAC unit is actively conditioning a building. ### Claim 6 A refrigerant leak management system of a heating, ventilation, and air conditioning (HVAC) unit comprising: a sensor configured to detect a refrigerant in an interior of an air handling enclosure; a plurality of airflow management assemblies configured to fluidly isolate the interior of the air handling enclosure in a closed configuration, the plurality of airflow management assemblies comprising a return inlet assembly, a supply outlet assembly, and a purge exhaust outlet assembly; and a controller configured to actuate the purge exhaust outlet assembly based on detection of the refrigerant by the sensor such that the purge exhaust outlet assembly transitions from a closed position of the purge exhaust outlet assembly to an open position of the purge exhaust outlet assembly that opens the interior of the air handling enclosure to an external environment. ### Claim 7 (depends on 6) The refrigerant leak management system of claim 6, wherein the controller is configured to actuate the plurality of airflow management assemblies into the closed configuration when the HVAC unit is in an OFF-cycle. ### Claim 8 (depends on 7) The refrigerant leak management system of claim 7, wherein the controller is configured to monitor the sensor only while the plurality of airflow management assemblies is in the closed configuration. ### Claim 9 (depends on 7) The refrigerant leak management system of claim 7, wherein the sensor is operational only while the plurality of airflow management assemblies is in the closed configuration. ### Claim 10 (depends on 6) The refrigerant leak management system of claim 6, comprising the air handling enclosure and a fan configured to draw conditioned air through the air handling enclosure generally along a flow path from the return inlet assembly toward the supply outlet assembly. ### Claim 11 (depends on 10) The refrigerant leak management system of claim 10, wherein the controller is configured to operate the refrigerant leak management system in an idle mode when the HVAC unit is in an ON-cycle to enable the HVAC unit to provide the conditioned air through the supply outlet assembly and to a conditioned interior space of a building. ### Claim 12 (depends on 6) The refrigerant leak management system of claim 6, wherein the return inlet assembly is configured to be disposed at a return inlet of the air handling enclosure, wherein the supply outlet assembly is configured to be disposed at a supply outlet of the air handling enclosure, and wherein purge exhaust outlet assembly is configured to be disposed at a purge exhaust outlet of the air handling enclosure. ### Claim 13 (depends on 6) The refrigerant leak management system of claim 6, wherein the controller is configured to maintain the return inlet assembly and supply outlet assembly in normally open positions during an ON-cycle of the HVAC unit and the purge exhaust outlet assembly in a normally closed position during the ON-cycle of the HVAC unit. ### Claim 14 (depends on 6) The refrigerant leak management system of claim 6, wherein the sensor is configured to detect a concentration of the refrigerant above a predefined concentration threshold. ### Claim 15 (depends on 6) The refrigerant leak management system of claim 6, wherein the controller is configured to actuate the purge exhaust outlet assembly based on the detection of the refrigerant by the sensor being a refrigerant concentration greater than a predefined concentration threshold. ### Claim 16 (depends on 6) The refrigerant leak management system of claim 6, wherein the controller is configured to block the HVAC unit from entering an ON-cycle based on the detection of the refrigerant by the sensor. ### Claim 17 (depends on 6) The refrigerant leak management system of claim 6, wherein the external environment is an unconditioned interior space of a building associated with the HVAC unit, or a space exterior to the building associated with the HVAC unit. ### Claim 18 (depends on 6) The refrigerant leak management system of claim 6, wherein the air handling enclosure is the air handling enclosure of a packaged HVAC unit or the air handling enclosure of an interior HVAC unit of a split-type HVAC system. ### Claim 19 (depends on 6) The refrigerant leak management system of claim 6, wherein the plurality of airflow management assemblies comprises a purge inlet assembly configured to be disposed at a purge inlet of the air handling enclosure, and wherein the controller is configured to maintain the purge inlet assembly in a normally closed position during an ON-cycle of the HVAC unit. ### Claim 20 (depends on 19) The refrigerant leak management system of claim 19, wherein the controller is configured to actuate the purge inlet assembly based on the detection of the refrigerant by the sensor to control an air flow entering the interior of the air handling enclosure from the external environment or an additional external environment. ### Claim 21 (depends on 6) The refrigerant leak management system of claim 6, wherein at least one airflow management assembly of the plurality of airflow management assemblies comprises a motorized damper configured to transition to an open position of the at least one airflow management assembly in response to being actuated by the controller. ### Claim 22 (depends on 6) The refrigerant leak management system of claim 6, wherein a particular airflow management assembly of the plurality of airflow management assemblies comprises a barometric damper configured to open in response to an air flow to enable the air flow to traverse the barometric damper. ### Claim 23 (depends on 22) The refrigerant leak management system of claim 22, wherein the particular airflow management assembly comprises a locking mechanism configured to selectively latch or unlatch the barometric damper of the particular airflow management assembly, wherein the locking mechanism is configured to maintain the barometric damper in a closed position of the particular airflow management assembly to block the air flow from traversing the particular airflow management assembly when locked. ### Claim 24 (depends on 23) The refrigerant leak management system of claim 23, wherein the locking mechanism comprises an actuator that latches or unlatches the barometric damper of the particular airflow management assembly in response to actuating control signals from the controller. ### Claim 25 A refrigerant leak management system of a heating, ventilation, and air conditioning (HVAC) system comprising: a plurality of airflow management assemblies configured to be coupled to an air handling enclosure; and a controller configured to actuate the plurality of airflow management assemblies to isolate air within the air handling enclosure before a sensor measures a refrigerant concentration in the air handling enclosure, wherein the controller is configured to direct isolated air from an interior of the air handling enclosure to an external environment via actuation of a purge exhaust outlet assembly of the plurality of airflow management assemblies when the refrigerant concentration is greater than a predefined concentration threshold. ### Claim 26 (depends on 25) The refrigerant leak management system of claim 25, comprising the sensor, wherein the sensor is disposed proximate to an evaporator coil within the air handling enclosure. ### Claim 27 (depends on 25) The refrigerant leak management system of claim 25, comprising a fan communicatively coupled to the controller, wherein the controller is configured to activate the fan to direct the isolated air from within the air handling enclosure through the purge exhaust outlet and into the external environment. ### Claim 28 (depends on 25) The refrigerant leak management system of claim 25, comprising the air handling enclosure, wherein the air handling enclosure comprises a return inlet configured to receive an air flow from a conditioned interior space of a building, a supply outlet configured to direct the air flow to the conditioned interior space of the building, and a purge exhaust outlet configured to direct the air flow into the external environment. ### Claim 29 (depends on 28) The refrigerant leak management system of claim 28, comprising a plurality of ducts that respectively fluidly couple the return inlet of the air handling enclosure to the conditioned interior space, the supply outlet to the conditioned interior space, and the purge exhaust outlet to the external environment. ### Claim 30 (depends on 28) The refrigerant leak management system of claim 28, wherein the plurality of airflow management assemblies comprises a return inlet assembly disposed at the return inlet, a supply outlet assembly disposed at the supply outlet, and the purge exhaust outlet assembly disposed at the purge exhaust outlet of the air handling enclosure. ### Claim 31 (depends on 30) The refrigerant leak management system of claim 30, wherein the controller is configured to, in response to the HVAC system entering an ON-cycle, enter an idle mode, wherein the refrigerant leak management system opens the return inlet assembly and opens the supply outlet assembly in the idle mode. ### Claim 32 (depends on 30) The refrigerant leak management system of claim 30, wherein the air handling enclosure comprises a purge inlet configured to direct a fresh air flow into the air handling enclosure from the external environment or an additional external environment, and wherein the plurality of airflow management assemblies comprises a purge inlet assembly disposed at the purge inlet. ### Claim 33 A method of operating a leak management system of a heating, ventilation, and air conditioning (HVAC) system comprising: in response to the HVAC system entering an OFF-cycle, closing a return inlet assembly and closing a supply outlet assembly of an air handling enclosure to block air from entering and exiting the air handling enclosure of the HVAC system; measuring a concentration of refrigerant within air of the air handling enclosure; and in response to the concentration of refrigerant being greater than a predetermined threshold, opening a purge exhaust outlet assembly and activating a supply fan disposed within the air handling enclosure to purge the air within the air handling enclosure through the purge exhaust outlet assembly and into an external environment. ### Claim 34 (depends on 33) The method of claim 33, comprising: measuring an additional concentration of refrigerant within the air handling enclosure; and in response to the additional concentration of refrigerant being greater than the predetermined threshold, increase a fan speed of the supply fan to purge the air from the air handling enclosure at a greater speed. ### Claim 35 (depends on 33) The method of claim 33, comprising: measuring an additional concentration of refrigerant within the air handling enclosure; and in response to the additional concentration of refrigerant being less than the predetermined threshold, opening the return inlet assembly, opening the supply outlet assembly, and enabling the HVAC system to subsequently enter an ON-cycle. ### Claim 36 (depends on 35) The method of claim 35, comprising: in response to the concentration of refrigerant or the additional concentration of refrigerant being less than the predetermined threshold, closing the purge exhaust outlet assembly when the purge exhaust outlet assembly is open. ### Claim 37 A refrigerant leak management system of a heating, ventilation, and air conditioning (HVAC) unit comprising: an air handler having a return inlet, a supply outlet, and a purge exhaust, the purge exhaust routing from an interior of the air handler to an external environment and being normally closed; a sensor configured to detect a refrigerant in an interior of the air handler; and a controller configured to open the purge exhaust upon detection of the refrigerant by the sensor. ### Claim 38 (depends on 37) The refrigerant leak management system of claim 37, wherein the controller is configured under standard operating conditions of the HVAC unit such that the return inlet and the supply outlet are both open. ### Claim 39 (depends on 38) The refrigerant leak management system of claim 38, wherein the purge exhaust is substantially closed under standard operating conditions of the HVAC unit. ### Claim 40 (depends on 38) The refrigerant leak management system of claim 38, wherein the controller is configured under a leak detection mode to collectively close the return inlet, the supply outlet, and the purge exhaust to a degree necessary to detect refrigerant. ### Claim 41 (depends on 39) The refrigerant leak management system of claim 39, wherein the controller is configured under a leak response mode to open the purge exhaust and to route airflow from the interior of the air handler to an external environment.