US 12,298,049 B2
System and method for identifying a refrigerant leak in multiple refrigeration circuits with one or more compressors
Rakesh Goel, Irving, TX (US); Siddarth Rajan, Addison, TX (US); and Vijay Kumar Sathyamurthi, Frisco, TX (US)
Assigned to Lennox Industries Inc., Richardson, TX (US)
Filed by Lennox Industries Inc., Richardson, TX (US)
Filed on Aug. 21, 2023, as Appl. No. 18/453,040.
Prior Publication US 2025/0067487 A1, Feb. 27, 2025
Int. Cl. F24F 11/36 (2018.01); F25B 41/24 (2021.01); F25B 41/40 (2021.01); F25B 49/00 (2006.01)
CPC F25B 49/005 (2013.01) [F25B 41/24 (2021.01); F25B 41/40 (2021.01); F25B 2400/06 (2013.01); F25B 2500/222 (2013.01); F25B 2700/195 (2013.01); F25B 2700/197 (2013.01); F25B 2700/21163 (2013.01); F25B 2700/21175 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A heating, ventilation, and air conditioning (HVAC) system configured to regulate a temperature of a space, the HVAC system comprising:
a set of refrigeration circuits comprising a first refrigeration circuit with one or more first compressors and a second refrigeration circuit with one or more second compressors, wherein:
the first refrigeration circuit is configured to receive a first flow of a first refrigerant from a first evaporator coil and to discharge the first flow of refrigerant at a first higher pressure than it was received;
the second refrigeration circuit is configured to receive a second flow of a second refrigerant from a second evaporator coil and to discharge the second flow of the second refrigerant at a second higher pressure than it was received;
a condenser configured to receive the first refrigerant and cool the first refrigerant flowing through;
a subcool sensor circuit configured to provide a subcool signal that indicates a subcool value associated with the condenser, wherein the subcool value corresponds to a temperature difference between a saturated refrigerant and a subcooled refrigerant associated with the condenser;
a superheat sensor circuit configured to provide a superheat signal that indicates a superheat value corresponding to a temperature difference between a superheated refrigerant and a saturated refrigerant associated with the first evaporator;
a refrigerant detection sensor circuit configured to detect a concentration of the first refrigerant in a volume; and
a processor operably coupled with the refrigerant detection sensor circuit, the subcool sensor circuit, and the superheat sensor circuit, and configured to:
obtain information related to the detected concentration of the first refrigerant in the volume;
compare the detected concentration of the first refrigerant with a threshold concentration; and
determine that the detected concentration of the first refrigerant exceeds the threshold concentration;
in response to determining that the detected concentration of the first refrigerant exceeds the threshold concentration:
receive the subcool signal from the subcool sensor circuit;
determine the subcool value based at least in part upon the subcool signal;
receive the superheat signal from the superheat sensor circuit;
determine the superheat value based at least in part upon the superheat signal;
determine that the subcool value is less than a threshold subcool value; and
determine that the superheat value is more than a threshold superheat value;
in response to determining that the subcool value is less than the threshold subcool value and that the superheat value is more than the threshold superheat value:
 determine that the first refrigerant is leaking from the first refrigeration circuit;
 isolate the first refrigeration circuit from other components of the HVAC system;
 execute a mitigation plan to dilute the leak of the first refrigerant from the first refrigeration circuit; and
 operate the second refrigeration circuit to provide air conditioning in response to an air conditioning demand.