Systems and methods for refrigerant leak management

Patent metadata

Field	Value
Publication number	US-10935454-B2
Application number	US-201815871698-A
Country	US
Kind code	B2
Filing date	Jan 15, 2018
Priority date	Dec 1, 2017
Publication date	Mar 2, 2021
Grant date	Mar 2, 2021

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.

First claim

The invention claimed is:

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 the purge exhaust being normally closed;
a sensor configured to detect a leaked refrigerant in the interior of the air handler; and
a controller configured to:
determine a current cycle of the HVAC unit;
operate in a first mode to close the return inlet, the supply outlet, and the purge exhaust in response to determining the HVAC unit is in an OFF-cycle to contain the leaked refrigerant within the interior of the air handler in the OFF-cycle of the HVAC unit; and
operate in a second mode, based on detection of the leaked refrigerant, to open the purge exhaust to route the leaked refrigerant from the interior of the air handler to the external environment.

2. The refrigerant leak management system of claim 1 , wherein the return inlet and the supply outlet are each normally open.

3. The refrigerant leak management system of claim 1 , wherein the purge exhaust substantially blocks flow therethrough while the purge exhaust is closed.

4. The refrigerant leak management system of claim 1 , wherein the controller is configured such that the supply outlet is closed during the second mode.

5. 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.

6. A refrigerant leak management system of a heating, ventilation, and air conditioning (HVAC) unit comprising:
a sensor configured to detect a leaked 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:
determine a current cycle of the HVAC unit;
actuate the plurality of airflow management assemblies into the closed configuration upon determining the current cycle is an OFF-cycle to contain the leaked refrigerant within the interior of the air handling enclosure; and
actuate the purge exhaust outlet assembly based on detection of the leaked 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.

7. The refrigerant leak management system of claim 6 , wherein the controller is configured to monitor the sensor while the plurality of airflow management assemblies are in the closed configuration.

8. 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 are in the closed configuration.

9. The refrigerant leak management system of claim 7 , wherein the sensor is operational only while the plurality of airflow management assemblies are in the closed configuration.

10. 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.

11. The refrigerant leak management system of claim 10 , wherein the controller is configured to operate the refrigerant leak management system in an idle mode upon determining 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.

12. 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 the purge exhaust outlet assembly is configured to be disposed at a purge exhaust outlet of the air handling enclosure.

13. The refrigerant leak management system of claim 6 , wherein the controller is configured to maintain the return inlet assembly and supply outlet assembly in open positions during an ON-cycle of the HVAC unit and to maintain the purge exhaust outlet assembly in a closed position during the ON-cycle of the HVAC unit.

14. The refrigerant leak management system of claim 6 , wherein the sensor is configured to detect a concentration of the leaked refrigerant above a predefined concentration threshold.

15. 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 leaked refrigerant by the sensor being a leaked refrigerant concentration greater than a predefined concentration threshold.

16. 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 leaked refrigerant by the sensor.

17. 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.

18. 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.

19. 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 closed position during an ON-cycle of the HVAC unit.

20. 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 leaked 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.

21. 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.

22. 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.

23. 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

Assignees

• Johnson Controls Tech Co

Inventors

• Kester Douglas A

Classifications

• G01M3/226 Primary

  for containers, e.g. radiators · CPC title

• F25B49/005

  of safety devices (F25B49/02 and F25B49/04 take precedence) · CPC title

• G01M3/2807 Primary

  for pipes (G01M3/2892, G01M3/30 take precedence) · CPC title

• F24F11/36

  to leakage of heat-exchange fluid · CPC title

• G01M3/40

  by using electric means, e.g. by observing electric discharges · CPC title