Refrigerant detection and control of HVAC system

Patent metadata

Field	Value
Publication number	US-11512867-B2
Application number	US-202016833047-A
Country	US
Kind code	B2
Filing date	Mar 27, 2020
Priority date	Mar 12, 2020
Publication date	Nov 29, 2022
Grant date	Nov 29, 2022

Abstract

A heating, ventilation, and/or air conditioning (HVAC) system includes a heat exchanger configured to exchange heat between a refrigerant and an air flow, a blower configured to induce the air flow across the heat exchanger, and a control board configured to receive an input indicative of a presence of refrigerant external to the heat exchanger and adjust operation of the blower based on the input.

First claim

What is claimed is:

1. A heating, ventilation, and/or air conditioning (HVAC) system, comprising:
a heat exchanger configured to exchange heat between a refrigerant and an air flow;
a blower configured to induce the air flow across the heat exchanger;
a thermostat configured to enable control of the HVAC system in a normal operating mode;
a thermostat relay configured to relay a power supply to the thermostat; and
a control board configured to:
receive an input indicative of a presence of refrigerant external to the heat exchanger, wherein the input comprises a voltage;
adjust operation of the blower based on the input by enabling an additional power supply to the blower in response to the voltage exceeding a threshold value; and
adjust the thermostat relay based on the input by suspending the power supply to the thermostat of the HVAC system in response to the voltage exceeding the threshold value.

2. The HVAC system of claim 1 , comprising a sensor configured to provide the input indicative of the presence of refrigerant external to the heat exchanger to the control board, wherein the sensor is disposed proximate to the heat exchanger.

3. The HVAC system of claim 1 , wherein the heat exchanger comprises an evaporator configured to exchange heat between the air flow and the refrigerant.

4. The HVAC system of claim 1 , wherein the control board is configured to adjust the thermostat relay to enable the power supply to the thermostat relay in the normal operating mode of the HVAC system.

5. The HVAC system of claim 1 , wherein the control board is configured to enable the power supply to the thermostat of the HVAC system by actuating the thermostat relay to a closed position in the normal operating mode of the HVAC system, and wherein the control board is configured to suspend the power supply to the thermostat by actuating the thermostat relay to an open position in response to the voltage exceeding the threshold value.

6. The HVAC system of claim 5 , comprising a blower relay configured to relay the additional power supply to the blower in an additional closed position of the blower relay and suspend the additional power supply to the blower in an additional open position of the blower relay.

7. A non-transitory computer-readable storage medium for a heating, ventilation, and/or air conditioning (HVAC) system comprising instructions that, when executed by a processor, cause the processor to:
receive an input indicative of a presence of refrigerant external to a heat exchanger of the HVAC system;
adjust operation of a blower of the HVAC system by enabling a power supply to the blower based on the input; and
suspend a normal operating mode of the HVAC system by suspending an additional power supply to a thermostat of the HVAC system based on the input.

8. The non-transitory computer-readable storage medium of claim 7 , wherein the input indicative of the presence of refrigerant is indicative of an amount of refrigerant, and wherein the instructions, when executed by the processor, cause the processor to:
determine a concentration of refrigerant in air based on the amount of refrigerant;
adjust the operation of the blower by enabling the power supply to the blower in response to the concentration of refrigerant in air exceeding a threshold value; and
suspend the normal operating mode of the HVAC system by suspending the additional power supply to the thermostat of the HVAC system in response to the concentration of refrigerant in air exceeding the threshold value.

9. The non-transitory computer-readable storage medium of claim 8 , wherein the instructions, when executed by the processor, cause the processor to determine the threshold value based on a type of the refrigerant, a configuration of the heat exchanger, a size of the heat exchanger, or a combination thereof.

10. The non-transitory computer-readable storage medium of claim 7 , wherein the instructions, when executed by the processor, cause the processor to operate the HVAC system in a normal operating mode based on an absence of the input.

11. The non-transitory computer-readable storage medium of claim 7 , wherein the instructions, when executed by the processor, cause the processor to:
actuate a thermostat relay to a closed position to enable the thermostat relay to relay the additional power supply to the thermostat in the normal operating mode of the HVAC system; and
actuate, in response to the input, the thermostat relay to an open position to block the thermostat relay from relaying the additional power supply to the thermostat.

12. A heating, ventilation, and/or air conditioning (HVAC) system, comprising:
a heat exchanger configured to exchange heat between a refrigerant and an air flow;
a blower configured to induce the air flow across the heat exchanger; and
a control board comprising:
a thermostat relay configured to selectively supply and suspend power to a thermostat of the HVAC system;
a blower relay configured to selectively supply and suspend additional power to the blower; and
a processor configured to control the thermostat relay and the blower relay, wherein the processor is configured to:
receive an input indicative of a presence of the refrigerant external to the heat exchanger;
adjust operation of the blower via control of the blower relay based on the input; and
actuate the thermostat relay to an open position in response to the input, wherein the thermostat relay in the open position is configured to suspend the power to the thermostat.

13. The HVAC system of claim 12 , wherein the processor is configured to adjust the blower relay to a closed position to supply the additional power to the blower in response to the input.

14. The HVAC system of claim 12 , comprising the thermostat, wherein the thermostat is configured to enable a normal operating mode of the HVAC system, and wherein the processor is configured to adjust the thermostat relay to a closed position to supply the power to the thermostat and enable the normal operating mode via the thermostat.

15. The HVAC system of claim 12 , wherein the heat exchanger comprises an evaporator configured to exchange heat between the air flow and the refrigerant.

Assignees

• Johnson Controls Tech Co
• Johnson Controls Tyco IP Holdings LLP

Inventors

• Atchison Shaun B
• Rigg Brian D

Classifications

• F24F11/81 Primary

  by controlling the air supply to heat-exchangers or bypass channels · CPC title

• F24F2110/66

  Volatile organic compounds [VOC] · CPC title

• F24F2110/00

  Control inputs relating to air properties · CPC title

• F24F11/36 Primary

  to leakage of heat-exchange fluid · CPC title

• F24F11/32

  Responding to malfunctions or emergencies · CPC title