Systems and methods for detecting refrigerant leaks in heating, ventilating, and air conditioning (HVAC) systems
The present disclosure relates to a refrigerant leak detection and mitigation system of a heating, ventilating, and air conditioning (HVAC) unit. The refrigerant leak detection and mitigation system includes a controller configured to determine a plurality of parameters correlated to refrigerant leak conditions based on data from a plurality of sensors. The controller is also configured to determine a probability of a refrigerant leak in the HVAC unit based on the plurality of parameters. Additionally, the controller is configured to provide a control signal to modify operation of the HVAC unit in response to comparison of the probability with a threshold value.
1 . A refrigerant leak detection and mitigation system of a heating, ventilating, and air conditioning (HVAC) unit, comprising a controller configured to:
determine respective values associated with a plurality of parameters of the HVAC unit based on data from a plurality of sensors, wherein the plurality of parameters comprises a presence of ice formed on a surface of an evaporator of the HVAC unit, and the plurality of sensors comprises an ice sensor configured to detect ice formed on the surface of the evaporator;
calculate a weighted value indicative of a refrigerant leak in the HVAC unit based on each of the respective values associated with the plurality of parameters; and
provide a control signal to modify operation of the HVAC unit in response to a comparison of the weighted value with a threshold value.
2 . The refrigerant leak detection and mitigation system of claim 1 , wherein the plurality of parameters comprises an amount that a liquid refrigerant temperature is below a refrigerant boiling point.
3 . The refrigerant leak detection and mitigation system of claim 1 , wherein the plurality of parameters comprises an amount of superheat.
4 . The refrigerant leak detection and mitigation system of claim 1 , wherein the controller is configured to calculate the weighted value indicative of the refrigerant leak based on a measured amount of ice on the surface of the evaporator, a measured amount of subcooling, and a measured amount of superheat.
5 . The refrigerant leak detection and mitigation system of claim 1 , wherein the ice sensor comprises a pressure sensor and a temperature sensor disposed between the evaporator and a compressor of the HVAC unit.
6 . The refrigerant leak detection and mitigation system of claim 5 , wherein the controller is configured to:
receive a pressure signal from the pressure sensor and a temperature signal from the temperature sensor, wherein the pressure signal and the temperature signal are indicative of a pressure and a temperature, respectively, of a refrigerant between the evaporator and the compressor of the HVAC unit; and
predict a respective value associated with an amount of ice based on the pressure signal and the temperature signal.
7 . The refrigerant leak detection and mitigation system of claim 6 , wherein the pressure sensor and the temperature sensor are disposed at a refrigerant outlet of the evaporator.
8 . The refrigerant leak detection and mitigation system of claim 7 , wherein the pressure sensor and the temperature sensor are integrated into a single body of a combination pressure temperature sensor.
9 . The refrigerant leak detection and mitigation system of claim 1 , wherein the surface of the evaporator is an outer surface of the evaporator, the ice sensor is disposed on the outer surface of the evaporator of the HVAC unit, and the controller is configured to determine a respective value associated with an amount of ice on the outer surface of the evaporator based on data from the ice sensor.
10 . The refrigerant leak detection and mitigation system of claim 1 , wherein the plurality of parameters comprises an amount of subcooling, the refrigerant leak detection and mitigation system comprises a pressure sensor and a temperature sensor disposed between a condenser and an expansion device of the HVAC unit, and the controller is configured to determine a respective value associated with the amount of subcooling based on signals received from the pressure sensor and the temperature sensor.
11 . The refrigerant leak detection and mitigation system of claim 1 , wherein the plurality of parameters comprises an amount of superheat, the refrigerant leak detection and mitigation system comprises a pressure sensor and a temperature sensor disposed between a compressor and a condenser of the HVAC unit, and the controller is configured to determine a respective value associated with the amount of superheat based on signals received from the pressure sensor and the temperature sensor.
12 . The refrigerant leak detection and mitigation system of claim 1 , wherein the plurality of parameters comprises an air temperature, and the controller is configured to determine a respective value associated with the air temperature based on data from an air temperature sensor.
13 . The refrigerant leak detection and mitigation system of claim 1 , wherein the controller is configured to provide the control signal to adjust a position of a damper to allow environmental air into the HVAC unit in response to the weighted value exceeding the threshold value.
14 . The refrigerant leak detection and mitigation system of claim 1 , wherein the controller is configured to provide the control signal to adjust a speed of a supply fan to increase airflow through the HVAC unit in response to the weighted value exceeding the threshold value.
15 . The refrigerant leak detection and mitigation system of claim 1 , wherein the controller is configured to provide the control signal to deactivate the HVAC unit in response to the weighted value exceeding the threshold value.
16 . The refrigerant leak detection and mitigation system of claim 1 , wherein the controller is configured to provide the control signal to adjust a speed of a variable speed supply fan proportional to the weighted value.
17 . A heating, ventilating, and air conditioning (HVAC) system having a condenser, an expansion device, an evaporator, and a compressor fluidly coupled to form a vapor compression system, wherein the HVAC system includes a refrigerant leak detection and mitigation system, comprising:
icing sensors, subcooling sensors, and superheat sensors communicatively coupled to a controller that is configured to:
determine an amount of icing, an amount of subcooling, and an amount of superheat based on measurements from the icing sensors, subcooling sensors, and superheat sensors, respectively;
determine a weighted calculation indicative of a refrigerant leak in the vapor compression system based on the amount of icing, the amount of subcooling, and the amount of superheat; and
provide a control signal to modify operation of the HVAC system in response to the weighted calculation exceeding a threshold value.
18 . The HVAC system of claim 17 , wherein the controller is configured to determine the weighted calculation indicative of the refrigerant leak using an equation that mathematically associates the weighted calculation with the amount of icing, the amount of subcooling, and the amount of superheat.
19 . The HVAC system of claim 17 , wherein the icing sensors comprise a pressure sensor and a temperature sensor disposed at a refrigerant outlet of the evaporator, and wherein the controller is configured to:
receive respective signals from the pressure sensor and the temperature sensor indicating a pressure and a temperature, respectively, of refrigerant in the vapor compression system between the evaporator and the compressor; and
determine the amount of icing based on the respective signals received from the pressure sensor and the temperature sensor.
20 . The HVAC system of claim 17 , wherein the icing sensors comprise an ice sensor disposed on an outer surface of the evaporator, and wherein the controller is configured to determine the amount of icing based on a signal received from the ice sensor.
21 . The HVAC system of claim 17 , wherein the subcooling sensors comprise a pressure sensor and a temperature sensor disposed at a refrigerant outlet of the condenser, and wherein the controller is configured to determine the amount of subcooling based on signals received from the pressure sensor and the temperature sensor.
22 . The HVAC system of claim 17 , comprising an air temperature sensor communicatively coupled to the controller, wherein the controller is configured to:
determine an air temperature based on signals received from the air temperature sensor; and
determine the amount of subcooling based on the air temperature.
23 . The HVAC system of claim 17 , wherein the superheat sensors comprise a pressure sensor and a temperature sensor disposed at a refrigerant outlet of the compressor, and wherein the controller is configured to:
receive respective signals from the pressure sensor and the temperature sensor indicating a pressure and a temperature of refrigerant in the vapor compression system between the compressor and the condenser;
determine an amount of discharge superheat based on the respective signals received from the pressure sensor and the temperature sensor; and
determine the amount of superheat based on the amount of discharge superheat.
24 . The HVAC system of claim 17 , comprising an air temperature sensor communicatively coupled to the controller, wherein the controller is configured to:
receive signals from the air temperature sensor indicating an air temperature;
determine the air temperature based on the signals received from the air temperature sensor; and
determine the amount of superheat based on the air temperature.
25 . The HVAC system of claim 17 , wherein the controller is configured to provide the control signal to adjust a position of a damper to allow fresh air into the HVAC system and adjust a speed of a supply fan to increase airflow through the HVAC system in response to the weighted calculation exceeding the threshold value.
26 . The HVAC system of claim 17 , wherein the controller is configured to provide the control signal to send an email, text message, or phone call to an electronic device.
27 . The HVAC system of claim 17 , wherein the controller is configured to provide the control signal to adjust a speed of a variable speed supply fan proportional to the weighted calculation.
28 . The HVAC system of claim 17 , wherein the superheat sensors comprise a pressure sensor and a temperature sensor disposed at a refrigerant inlet of the compressor, and wherein the controller is configured to:
receive respective signals from the pressure sensor and the temperature sensor indicating a pressure and a temperature of refrigerant in the vapor compression system between the evaporator and the compressor;
determine an amount of suction superheat based on the respective signals received from the pressure sensor and the temperature sensor; and
determine the amount of superheat based on the amount of suction superheat.
29 . A heating, ventilating, and air conditioning (HVAC) system having a condenser, an expansion device, an evaporator, and a compressor fluidly coupled to form a vapor compression system, wherein the HVAC system includes a refrigerant leak detection and mitigation system, comprising:
icing sensors, subcooling sensors, and superheat sensors communicatively coupled to a controller that is configured to:
determine an icing value indicative of icing on the evaporator, a subcooling value, and a superheat value based on measurements from the icing sensors, subcooling sensors, and superheat sensors, respectively, wherein the subcooling value comprises an amount that a liquid refrigerant temperature is below a refrigerant boiling point;
calculate a weighted value indicative of a refrigerant leak in the vapor compression system based on the icing value, the subcooling value, and the superheat value; and
provide a control signal to modify operation of the HVAC system in response to the weighted value exceeding a threshold value.
30 . The HVAC system of claim 29 , wherein the controller is configured to provide the control signal to adjust a speed of a variable speed supply fan proportional to the weighted value indicative of the refrigerant leak.
31 . The HVAC system of claim 29 , wherein the controller is configured to provide the control signal to modify operation of the HVAC system in response to the icing value exceeding an additional threshold value.
32 . The HVAC system of claim 29 , wherein the controller is configured to provide the control signal to modify operation of the HVAC system in response to the subcooling value exceeding an additional threshold value.
33 . The HVAC system of claim 29 , wherein the controller is configured to provide the control signal to modify operation of the HVAC system in response to the superheat value exceeding an additional threshold value.
34 . The HVAC system of claim 29 , wherein the weighted value comprises a weighted summation of the icing value, the subcooling value, and the superheat value.
35 . The HVAC system of claim 29 , wherein the icing value comprises an amount of ice formed on an outer surface of the evaporator.