# US 2019/0170384 A1 · Ultraviolet (uv) light-based 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 2019/0170384 A1 - Document ID: US20190170384A1 - Status: Published application - Kind: A1 - Application number: 15/871,691 - Filed: 2018-01-15 - Published: 2019-06-06 - Earliest claimed: 2017-12-01 - Assignees: Johnson Controls Technology Company - Applicants: Johnson Controls Technology Company - Inventors: William F. McQuade; Neelkanth Gupte - Web page: https://patentgrep.com/patent/US20190170384A1 ## CPC - F24F 11/36: to leakage of heat-exchange fluid - F25B 49/02: for compression type machines, plants or systems - G01M 3/20: using special tracer materials, e.g. dye, fluorescent material, radioactive material - G01N 21/63: optically excited - G05B 15/02: electric - F25B 13/00: Compression machines, plants or systems, with reversible cycle (defrosting cycles F25B47/02) - F25B 49/005: {of safety devices (F25B49/02 and F25B49/04 take precedence)} - F25B 2500/222: Detecting refrigerant leaks - G01N 2021/0193: {the sample being taken from a stream or flow to the measurement cell} - 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 - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) ## Abstract A leak detection system of a heating, ventilating, and air conditioning (HVAC) system includes a sensor configured to detect a UV tracer in a monitored gas volume of the HVAC system. The leak detection system also includes a controller communicatively coupled to the sensor. The controller is configured to modify operation of the HVAC system in response to the sensor detecting the UV tracer in the monitored gas volume. ## Claims ### Claim 1 A leak detection system of a heating, ventilating, and air conditioning (HVAC) system, comprising: a sensor configured to detect an ultraviolet (UV) tracer in a monitored gas volume of the HVAC system; and a controller communicatively coupled to the sensor, wherein the controller is configured to modify operation of the HVAC system in response to the sensor detecting the UV tracer in the monitored gas volume. ### Claim 2 (depends on 1) The system of claim 1, wherein the sensor is configured to measure a concentration of the UV tracer within the monitored gas volume. ### Claim 3 (depends on 1) The system of claim 1, wherein the controller is configured to determine a concentration of leaked refrigerant in the monitored gas volume based on the measured concentration of the UV tracer within the monitored gas volume. ### Claim 4 (depends on 3) The system of claim 3, wherein the controller is configured to modify the operation of the HVAC system when the concentration of the leaked refrigerant in the monitored gas volume is greater than a predetermined threshold value. ### Claim 5 (depends on 1) The system of claim 1, comprising a sample preparation unit configured to collect a gas sample from the monitored gas volume and to prepare the gas sample for UV analysis. ### Claim 6 (depends on 5) The system of claim 5, comprising a valve communicatively coupled to the controller, wherein the valve is configured to actuate to collect the gas sample from the monitored gas volume in response to control signals from the controller. ### Claim 7 (depends on 5) The system of claim 5, wherein the sample preparation unit comprises a compressor configured to compress the gas sample to prepare the gas sample for the UV analysis. ### Claim 8 (depends on 1) The system of claim 1, wherein the sensor comprises a UV tracer detection unit configured to detect a concentration of the UV tracer in a sample collected from the monitored gas volume. ### Claim 9 (depends on 8) The system of claim 8, wherein the UV tracer detection unit comprises: a light source configured to irradiate the gas sample with emitted light; and a light detector configured to detect modified light from the gas sample, wherein the emitted light interacts with the sample to generate the modified light. ### Claim 10 (depends on 9) The system of claim 9, wherein the sensor is configured to use a difference between an intensity of the emitted light and an intensity of the modified light to detect the concentration of the UV tracer in the sample. ### Claim 11 (depends on 9) The system of claim 9, wherein a frequency of the emitted light is different than a frequency of the modified light, and wherein the sensor is configured to correlate an intensity of the modified light with the concentration of the UV tracer in the sample. ### Claim 12 (depends on 9) The system of claim 9, wherein the controller is configured to correlate the UV tracers being present in the sample. ### Claim 13 (depends on 9) The system of claim 9, wherein the UV tracer detection unit comprises a reflective surface configured to direct the emitted light to the sample. ### Claim 14 (depends on 9) The system of claim 9, wherein the UV tracer detection unit comprises a reflective surface configured to direct modified light to the light detector. ### Claim 15 (depends on 9) The system of claim 9, wherein the UV tracer detection unit comprises a plurality of reflective surfaces, wherein the plurality of reflective surfaces is configured to cooperate to direct the emitted light to the gas sample, to direct the modified light to the light detector, or a combination thereof. ### Claim 16 (depends on 13) The system of claim 13, wherein the reflective surface is a surface of a duct of the HVAC system. ### Claim 17 (depends on 9) The system of claim 9, wherein the light detector comprises a camera configured to detect the modified light from the gas sample. ### Claim 18 (depends on 9) The system of claim 9, wherein the light detector comprises a photovoltaic device that is configured to detect the modified light from the gas sample. ### Claim 19 (depends on 1) The system of claim 1, wherein the sensor is disposed within a duct of the HVAC system, and wherein the monitored gas volume comprises conditioned air within the HVAC system. ### Claim 20 (depends on 1) The system of claim 1, wherein the sensor is disposed within a casing of an interior HVAC unit of the HVAC system, and wherein the monitored gas volume is within the casing of the interior HVAC unit. ### Claim 21 (depends on 20) The system of claim 20, wherein the HVAC system comprises an evaporator disposed within the casing of the interior HVAC unit, and wherein the UV tracer sensor is disposed near the evaporator. ### Claim 22 (depends on 1) The system of claim 1, wherein the sensor is disposed within a casing of an exterior HVAC unit of the HVAC system, and wherein the monitored gas volume is within the casing of the exterior HVAC unit. ### Claim 23 (depends on 1) The system of claim 1, wherein the HVAC system comprises a condenser disposed within the casing of the exterior HVAC unit, and wherein the UV tracer sensor is disposed near the condenser. ### Claim 24 A leak detection system of a heating, ventilating, and air conditioning (HVAC) system, comprising: a vapor compression system configured to circulate a refrigerant that includes an ultraviolet (UV) tracer; a sensor configured to measure a concentration of the UV tracer in a monitored gas volume near the vapor compression system of the HVAC system; a controller configured to: determine a concentration of refrigerant in the monitored gas volume based on the concentration of the UV tracer measured by the sensor; and modify operation of the HVAC system when the concentration of refrigerant in the monitored gas volume is greater than a predetermined threshold value. ### Claim 25 (depends on 24) The system of claim 24, wherein the sensor is configured to collect a gas sample from the monitored gas volume when the controller determines that the HVAC system is idle. ### Claim 26 (depends on 24) The system of claim 24, wherein the vapor compression system comprises an evaporator, and wherein the sensor is disposed near the evaporator. ### Claim 27 (depends on 24) The system of claim 24, comprising a sample preparation unit fluidly coupled to a UV tracer detection unit of the sensor, wherein the sample preparation unit is configured to collect a gas sample from the monitored gas volume and prepare the gas sample, and wherein the UV tracer detection unit is configured to measure the concentration of the UV tracer in the gas sample. ### Claim 28 (depends on 27) The system of claim 27, wherein the sample preparation unit comprises a compressor configured to compress the gas sample before the UV tracer detection unit measures the concentration of the UV tracer in the gas sample. ### Claim 29 (depends on 24) The system of claim 24, wherein the sensor comprises a UV tracer detection unit comprising a light source configured to irradiate the gas sample with emitted light and a light detector configured to detect modified light from the gas sample, and wherein the modified light has a reduced intensity, a different frequency, or a combination thereof, compared to the emitted light due to interactions between the emitted light and the gas sample. ### Claim 30 (depends on 29) The system of claim 29, wherein the UV tracer detection unit comprises a plurality of reflective materials configured to cooperate to direct the emitted light to the gas sample, to direct the modified light to the light detector, or a combination thereof. ### Claim 31 (depends on 30) The system of claim 30, wherein the reflective materials are disposed along an inner surface of a casing of an indoor HVAC unit or outdoor HVAC unit of the HVAC system. ### Claim 32 (depends on 29) The system of claim 29, wherein the light detector comprises a camera or a photovoltaic device configured to detect the modified light from the gas sample. ### Claim 33 (depends on 24) The system of claim 24, wherein the sensor is disposed within a duct of the HVAC system, and wherein the monitored gas volume comprises conditioned air within the HVAC system. ### Claim 34 A method of operating a sensor to detect a refrigerant in a monitored gas volume associated with a heating, ventilation, and air conditioning (HVAC) system, the method comprising: collecting a sample from the monitored gas volume; measuring an amount of ultraviolet (UV) tracer in the sample; determining an amount of refrigerant present in the monitored gas volume based at least in part on the measured amount of UV tracer in the sample; and modifying operation of the HVAC system in response to determining that the amount of refrigerant present in the monitored gas volume is greater than a predetermined threshold value, wherein modifying comprises at least impeding the HVAC system from activating. ### Claim 35 (depends on 34) The method of claim 34, comprising disabling activation of the HVAC system before collecting the sample. ### Claim 36 (depends on 34) The method of claim 34, comprising preparing the sensor before collecting the sample. ### Claim 37 (depends on 34) The method of claim 34, wherein modifying operation comprises activating one or more fans associated with ductwork of the HVAC system.