Refrigerant gas sensing system

Patent metadata

Field	Value
Publication number	US-10996131-B2
Application number	US-201815871681-A
Country	US
Kind code	B2
Filing date	Jan 15, 2018
Priority date	Dec 1, 2017
Publication date	May 4, 2021
Grant date	May 4, 2021

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.

First claim

The invention claimed is:

1. A refrigerant gas sensing system of a heating, ventilating, and air conditioning (HVAC) system, comprising:
a controller communicatively coupled to a sample preparation unit, an ignition unit, a combustion product detection unit, and a control panel of the HVAC system, wherein the controller is configured to:
provide a first control signal to the sample preparation unit to collect a sample from a monitored gas volume that is separate from a refrigerant circuit of the HVAC system;
provide a second control signal to the sample preparation unit to increase a pressure of the sample to generate a pressurized sample;
provide a third control signal to the ignition unit to introduce an ignition source to the pressurized sample;
receive a fourth signal from the combustion product detection unit indicative of an amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample;
determine an amount of leaked refrigerant in the monitored gas volume based on the measured amount of combustion product; and
output a fifth signal to the control panel of the HVAC indicative of the amount of leaked refrigerant in the monitored gas volume.

2. The refrigerant gas sensing system of claim 1 , comprising the 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.

3. The refrigerant gas sensing system of claim 2 , wherein the sample preparation unit comprises a compressor configured to increase the pressure of the sample to prepare the sample for introducing the ignition source to the pressurized sample.

4. The refrigerant gas sensing system of claim 1 , comprising the ignition unit configured to introduce the ignition source to the pressurized sample to generate the combustion product.

5. The refrigerant gas sensing system of claim 4 , wherein the ignition source is a spark plug.

6. The refrigerant gas sensing system of claim 1 , wherein introducing the ignition source to the pressurized sample comprises flowing the pressurized sample through the ignition source.

7. The refrigerant gas sensing system of claim 1 , comprising the 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 pressurized sample after the ignition source is introduced to the pressurized sample.

8. The refrigerant gas sensing system of claim 1 , comprising the 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 pressurized sample after the ignition source is introduced to the pressurized sample.

9. The refrigerant gas sensing system of claim 1 , comprising the combustion product detection unit having a light detector configured to detect light emitted from the ignition source during sample ignition to detect the amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample.

10. The refrigerant gas sensing system of claim 1 , comprising the combustion product detection unit having a piezoelectric material that detects the amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample based on a modified electrical property of the piezoelectric material.

11. The refrigerant gas sensing system of claim 1 , wherein the refrigerant gas sensing system comprises a pressure sensor, wherein the pressure sensor is configured to measure the pressure of the pressurized sample after providing the third control signal to the ignition unit to introduce the ignition source to the pressurized sample.

12. The refrigerant gas sensing system of claim 1 , wherein the monitored gas volume is within an interior volume of a casing of a HVAC unit of the HVAC system.

13. The refrigerant gas sensing system of claim 1 , wherein the refrigerant gas sensing system is disposed near an evaporation coil of the HVAC system.

14. The refrigerant gas sensing system of claim 1 , wherein the combustion product comprises hydrogen fluoride and hydrogen chloride.

15. A heating, ventilating, and air conditioning (HVAC) system, comprising:
a first compressor configured to compress a flow of refrigerant in a refrigerant circuit of the HVAC system; and
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 that is distinct from the refrigerant circuit and prepare the sample for introducing an ignition source to the sample, wherein the sample preparation unit comprises a second compressor configured to compress the sample to generate a pressurized sample;
an ignition unit fluidly coupled to the sample preparation unit and configured to introduce the ignition source to the pressurized sample to convert refrigerant in the pressurized sample into combustion product; and
a combustion product detection unit fluidly coupled to the ignition unit and configured to measure and provide an indication of an amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample; and a control unit communicatively coupled to the combustion product detection unit, wherein the control unit is configured to receive the indication of the amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample, and determine and amount of leaked refrigerant in the monitored gas volume based on the indication.

16. The system of claim 15 , 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 pressurized sample after the ignition source is introduced to the pressurized sample, and determine an amount of leaked refrigerant in the monitored gas volume based on the indication.

17. The system of claim 16 , 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.

18. The system of claim 15 , wherein the combustion product detection unit comprises a light detector configured to optically detect the amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample.

19. The system of claim 18 , 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 pressurized sample after the ignition source is introduced to the pressurized sample.

20. The system of claim 18 , wherein the light detector is configured to detect a change in a property of light traversing the pressurized sample to optically detect the amount of combustion product in the pressurized sample after the ignition source is introduced to the pressurized sample.

21. The system of claim 15 , wherein the combu

Assignees

• Johnson Controls Tech Co

Inventors

• Mcquade William F
• Gupte Neelkanth

Classifications

• G01M3/20 Primary

  using special tracer materials, e.g. dye, fluorescent material, radioactive material · CPC title

• G01M3/207

  calibration arrangements · CPC title

• G01M3/38

  by using light (G01M3/02 takes precedence) · CPC title

• F25B2500/222

  Detecting refrigerant leaks · CPC title

• G01M3/16 Primary

  using electric detection means ({G01M3/045,} G01M3/06, G01M3/12, G01M3/20, G01M3/24, G01M3/26 take precedence) · CPC title