# US 2019/0170598 A1 · Refrigerant gas sensing system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0170598 A1 - Document ID: US20190170598A1 - Status: Published application - Kind: A1 - Application number: 15/871,681 - 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/US20190170598A1 ## CPC - G01M 3/16: using electric detection means ({G01M3/045,} G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence) - F25B 49/005: {of safety devices (F25B49/02 and F25B49/04 take precedence)} - G01M 3/20: using special tracer materials, e.g. dye, fluorescent material, radioactive material - G01M 3/207: {calibration arrangements} - G01M 3/38: by using light (G01M3/02 takes precedence) - F25B 2500/222: Detecting refrigerant leaks - G01M: TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS ## Abstract A refrigerant gas sensing system of a heating, ventilating, and air conditioning (HVAC) system, wherein the refrigerant gas sensing system is configured to collect a sample from a monitored gas volume, to introduce an ignition source to the sample, to detect an amount of combustion product in the sample after ignition, to determine an amount of leaked refrigerant in the monitored gas volume based on the measured amount of combustion product, and to indicate the amount of leaked refrigerant in the monitored gas volume. ## Claims ### Claim 1 A refrigerant gas sensing system of a heating, ventilating, and air conditioning (HVAC) system, wherein the refrigerant gas sensing system is configured to: collect a sample from a monitored gas volume; introduce an ignition source to the sample; detect an amount of combustion product in the sample after the ignition source is introduced to the sample; determine an amount of leaked refrigerant in the monitored gas volume based on the measured amount of combustion product; and indicate the amount of leaked refrigerant in the monitored gas volume. ### Claim 2 (depends on 1) The refrigerant gas sensing system of claim 1, comprising a sample preparation unit that is configured to collect the sample from the monitored gas volume and to prepare the sample for introducing the ignition source to the sample. ### Claim 3 (depends on 2) The refrigerant gas sensing system of claim 2, wherein the sample preparation unit comprises a compressor configured to increase a pressure of the sample to prepare the sample for introducing the ignition source to the sample. ### Claim 4 (depends on 1) The refrigerant gas sensing system of claim 1, comprising an ignition unit configured to introduce the ignition source to the sample to generate the combustion product. ### Claim 5 (depends on 4) The refrigerant gas sensing system of claim 4, wherein the ignition source is a spark plug. ### Claim 6 (depends on 1) The refrigerant gas sensing system of claim 1, wherein introducing the ignition source to the sample comprises flowing the sample through the ignition source. ### Claim 7 (depends on 1) The refrigerant gas sensing system of claim 1, comprising a combustion product detection unit configured to detect a change in an electrical property of a material to detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 8 (depends on 1) The refrigerant gas sensing system of claim 1, comprising a combustion product detection unit having a light source, a surface, and a light detector, wherein the combustion product detection unit is configured to detect a change in an optical property of the surface to detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 9 (depends on 1) The refrigerant gas sensing system of claim 1, comprising a combustion product detection unit having a light detector configured to detect light emitted from an ignition source during sample ignition to detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 10 (depends on 1) The refrigerant gas sensing system of claim 1, comprising a combustion product detection unit having a piezoelectric material that detects the amount of combustion product in the sample after the ignition source is introduced to the sample based on a modified electrical property of the piezoelectric material. ### Claim 11 (depends on 1) The refrigerant gas sensing system of claim 1, wherein the refrigerant gas sensing system comprises a pressure sensor. ### Claim 12 (depends on 1) The refrigerant gas sensing system of claim 1, comprising a control unit configured to: receive a first signal indicative of the amount of combustion product in the sample after the ignition source is introduced to the sample, determine the amount of leaked refrigerant in the monitored gas volume, and provide a second signal that indicates the amount of leaked refrigerant in the monitored gas volume. ### Claim 13 (depends on 1) The refrigerant gas sensing system of claim 1, wherein the refrigerant gas sensing system is disposed within a casing of a HVAC unit of the HVAC system. ### Claim 14 (depends on 1) The refrigerant gas sensing system of claim 1, wherein the refrigerant gas sensing system is disposed near an evaporation coil of the HVAC system. ### Claim 15 (depends on 1) The refrigerant gas sensing system of claim 1, wherein the refrigerant gas sensing system is configured to collect the sample from the monitored gas volume while the HVAC system is idle. ### Claim 16 (depends on 1) The refrigerant gas sensing system of claim 1, wherein the refrigerant gas sensing system is communicatively coupled to a HVAC controller of the HVAC system and configured to indicate to the HVAC controller the amount of leaked refrigerant in the monitored gas volume. ### Claim 17 (depends on 1) The refrigerant gas sensing system of claim 1, wherein the combustion product comprises a plurality of chemical species. ### Claim 18 (depends on 1) The refrigerant gas sensing system of claim 1, wherein combustion product comprises hydrogen fluoride (HF) or hydrofluoric acid. ### Claim 19 A heating, ventilating, and air conditioning (HVAC) system having a refrigerant gas sensing system, wherein the refrigerant gas sensing system comprises: a sample preparation unit configured to collect a sample of gas from a monitored gas volume and prepare the sample for introducing the ignition source to the sample; an ignition unit configured to introduce the ignition source to the sample to convert refrigerant in the sample into combustion product; and a combustion configured to measure and provide an indication of an amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 20 (depends on 19) The system of claim 19, wherein the refrigerant gas sensing system comprises a control unit communicatively coupled to the sample preparation unit, the ignition unit, and the combustion product detection unit of the refrigerant gas sensing system, wherein the control unit is configured to receive the indication of the amount of combustion product in the sample after the ignition source is introduced to the sample, and determine an amount of leaked refrigerant in the monitored gas volume based on the indication. ### Claim 21 (depends on 20) The system of claim 20, comprising a HVAC controller communicatively coupled to the control unit of the refrigerant gas sensing system, wherein the HVAC controller is configured to control operation of the HVAC system based, at least in part, on the determined amount of leaked refrigerant. ### Claim 22 (depends on 19) The system of claim 19, wherein the sample preparation unit comprises a compressor configured to increase a pressure of the sample. ### Claim 23 (depends on 19) The system of claim 19, wherein the combustion product detection unit comprises a light detector configured to optically detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 24 (depends on 23) The system of claim 23, wherein the light detector is configured to detect a change in an optical property of a surface to optically detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 25 (depends on 23) The system of claim 23, wherein the light detector is configured to detect a change in a property of light traversing the sample to optically detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 26 (depends on 19) The system of claim 19, wherein the combustion product detection unit comprises a pressure sensor configured to detect a change in a pressure of the sample to detect the amount of combustion product in the sample after the ignition source is introduced to the sample. ### Claim 27 A method of operating a refrigerant gas sensing system of a heating, ventilating, and air conditioning (HVAC) system, comprising: collecting and preparing a sample from a monitored gas volume associated with the HVAC system; introducing an ignition source to the sample and measuring an amount of combustion products in the sample after ignition; determining an amount of leaked refrigerant present in the monitored gas volume based, at least in part, on the measured amount of combustion products in the sample after ignition; and modifying operation of the HVAC system when the amount of leaked refrigerant in the monitored gas volume is above a predetermined threshold value. ### Claim 28 (depends on 27) The method of claim 27, wherein the modifying operation comprises impeding the HVAC system from resuming normal operation. ### Claim 29 (depends on 27) The method of claim 27, comprising collecting and preparing the sample when the HVAC system is idle. ### Claim 30 (depends on 27) The method of claim 27, wherein the modifying operation comprises generating an alarm. ### Claim 31 (depends on 27) The method of claim 27, wherein the modifying operation comprises activating one or more fans associated with ductwork of the HVAC system.