Systems and methods for detecting degradation of a component in an air conditioning system
A method including: determining whether a cooling system is operating in a cooling mode, such that the cooling system is not operating in a reheat mode, a humidification mode or a dehumidification mode; determining whether the cooling system is operating in a compressor mode, such that the cooling system is not operating in a pump refrigerant economization mode; determining whether the cooling system is at steady-state; and if the cooling system is operating in the cooling mode and the compressor mode and is at steady-state, evaluating one or more rules to determine if a degradation symptom exists for the cooling system. The method further includes: subsequent to the evaluation, generating a degradation evaluation value to indicate whether the one or more rules are satisfied; and based on the degradation evaluation value, generating an alarm signal or performing a countermeasure.
1. A method comprising: determining a cooling system, configured to operate in each of a compressor mode, a reheat mode, a humidification mode, a dehumidification mode and a pump refrigerant economization mode, is operating in a cooling mode, such that the cooling system is not operating in the reheat mode, the humidification mode or the dehumidification mode; determining the cooling system is operating in the compressor mode, such that the cooling system is not operating in the pump refrigerant economization mode; determining the cooling system is at steady-state; in response to the cooling system being operated in the cooling mode and the compressor mode and being at steady-state, performing an evaluation process including evaluating one or more first rules to determine if a degradation symptom exists for the cooling system, wherein the one or more first rules are associated with the cooling system including a single cooling circuit, evaluating one or more conditions, wherein the one or more conditions are associated with the cooling system including dual cooling circuits, and determining if the one or more conditions are satisfied and, as a result of the one or more conditions being satisfied, evaluating one or more second rules to determine if a degradation symptom exists for the cooling system; subsequent to performing the evaluation process, generating a degradation evaluation value to indicate whether the one or more first rules are satisfied or the one or more second rules are satisfied; and based on the degradation evaluation value, generating an alarm signal or performing a countermeasure.
2. The method of claim 1 , wherein the evaluating of the one or more first rules includes determining whether (i) an open percentage of an expansion valve is greater than or equal to a first predetermined value, and (ii) a superheat temperature is greater than or equal to a product of a coefficient and a superheat setpoint.
3. The method of claim 2 , wherein the determining of whether the one or more first rules are satisfied includes determining whether a call for cooling percentage is less than a second predetermined value.
4. The method of claim 2 , wherein the determining of whether the one or more first rules are satisfied includes determining whether a condenser pressure is less than a condenser pressure setpoint.
5. The method of claim 1 , wherein:
the determining of whether the one or more second rules are satisfied includes determining
whether an open percentage of a first expansion valve of a first cooling circuit is greater than or equal to a maximum of (i) a product of an open percentage of a second expansion valve of a second cooling circuit and a first constant, and (ii) a sum of the open percentage of the second expansion valve and a second constant, or
whether the open percentage of the second expansion valve is greater than a maximum of (i) a product of the open percentage of the first expansion valve and a third constant, and (ii) a sum of the open percentage of the first expansion valve and a fourth constant; and
the first constant, the second constant, the third constant and the fourth constant are different values and are greater than zero and not equal to one.
6. The method of claim 5 , wherein the open percentage of the first expansion valve and the open percentage of the second expansion valve are greater than zero.
7. The method of claim 1 , wherein:
the determining of whether the one or more second rules are satisfied includes determining
whether an open percentage of a first expansion valve of a first cooling circuit is greater than or equal to a maximum of (i) a product of an open percentage of a second expansion valve of a second cooling circuit and a first constant, and (ii) a sum of the open percentage of the second expansion valve and a second constant, and
whether the open percentage of the second expansion valve is greater than a maximum of (i) a product of the open percentage of the first expansion valve and a third constant, and (ii) a sum of the open percentage of the first expansion valve and a fourth constant; and
the first constant, the second constant, the third constant and the fourth constant are different values and are greater than zero and not equal to one.
8. The method of claim 7 , wherein the open percentage of the first expansion valve and the open percentage of the second expansion valve are greater than zero.
9. The method of claim 1 , further comprising:
iteratively evaluating the one or more first rules to determine if a degradation symptom exists for the cooling system;
subsequent to each of the iteratively performed evaluations, generating a respective degradation evaluation value to indicate whether the one or more first rules are satisfied;
incrementing a counter for each of the degradation evaluation values indicating that the one or more first rules are satisfied; and
determining that a value of the counter is greater than or equal to a predetermined threshold and generating the alarm signal or performing the countermeasure as a result of the value of the counter being greater than or equal to the predetermined threshold.
10. The method of claim 9 , wherein the one or more first rules are for a single parameter.
11. The method of claim 9 , wherein the one or more first rules are for multiple parameters.
12. The method of claim 1 , further comprising controlling one or more cooling circuits based on the degradation evaluation value, wherein each of the one or more cooling circuits includes a respective compressor, condenser, expansion valve, and evaporator.
13. The method of claim 1 , further comprising adjusting a fault relevancy value based on the degradation evaluation value, wherein the alarm signal is generated or the countermeasure is performed if the fault relevancy value reaches a predetermined threshold.
14. The method of claim 1 , wherein the dual cooling circuits include:
a first cooling circuit including a first compressor, a first evaporator, a first condenser, a first expansion valve; and
a second cooling circuit including a second compressor, a second evaporator, a second condenser, a second expansion valve.
15. The method of claim 1 , further comprising:
iteratively evaluating the one or more second rules to determine if a degradation symptom exists for the cooling system;
subsequent to each of the iteratively performed evaluations, generating a respective degradation evaluation value to indicate whether the one or more second rules are satisfied;
incrementing a counter for each of the degradation evaluation values indicating that the one or more second rules are satisfied; and
determining a value of the counter is greater than or equal to a predetermined threshold and generating the alarm signal or performing the countermeasure as a result of the value of the counter being greater than or equal to the predetermined threshold.
16. The method of claim 1 , wherein:
the first rules include
a rule 1 for determining whether an open percentage of an expansion valve is greater than or equal to a first predetermined value and a superheat temperature is greater than or equal to a superheat setpoint and either a condenser pressure is less than a product of a second predetermined value and the superheat setpoint or a call for cooling percentage is less than or equal to a predetermined percentage,
a rule 2 for determining whether the open percentage of the expansion valve is greater than or equal to the first predetermined value and the superheat temperature is greater than or equal to the superheat setpoint and the condenser pressure is less than a product of the second predetermined value and a condenser setpoint, and
a rule 3 for determining whether the open percentage of the expansion valve is greater than or equal to the first predetermined value and the superheat temperature is greater than or equal to the superheat setpoint and the call for cooling percentage is less than or equal to the predetermined percentage; and
the first predetermined value, the second predetermined value, the superheat setpoint, the predetermined percentage and the condenser setpoint are greater than zero and not equal to one.
17. The method of claim 1 , wherein:
the second rules include
a rule 1 for determining whether an open percentage of a first expansion valve of a first cooling circuit minus an open percentage of a second expansion valve of a second cooling circuit is greater than or equal to a first predetermined percentage,
a rule 2 for determining whether first conditions exist or a second condition exists,
the first conditions include
the open percentage of the second expansion valve is greater than or equal to a first predetermined value,
a superheat temperature of the second cooling circuit is greater than or equal to a product of a second predetermined value and a superheat setpoint, and
a call for cooling percentage is less than a second predetermined percentage, and
the second condition includes the superheat temperature of the second cooling circuit minus a superheat temperature of the first cooling circuit is greater than a third predetermined value;
a rule 3 for determining whether the open percentage of the first expansion valve is greater than a maximum of (i) a product of the open percentage of the second expansion valve and a fourth predetermined value, and (ii) a sum of the open percentage of the second expansion valve and a third predetermined percentage;
a rule 4 of determining whether the open percentage of the second expansion valve is greater than a maximum of (i) a product of the open percentage of the first expansion valve and a fifth predetermined value, and (ii) a sum of the open percentage of the first expansion valve and a fourth predetermined percentage; and
the first predetermined value, the second predetermined value, the third predetermined value, the fourth predetermined value, the fifth predetermined value, the first predetermined percentage, the second predetermined percentage, the third predetermined percentage and the fourth predetermined percentage are greater than zero and not equal to one.
18. A method comprising: determining a cooling system configured to operate in each of a compressor mode, a reheat mode, a humidification mode, a dehumidification mode and a pump refrigerant economization mode, is operating in a cooling mode, such that the cooling system is not operating in the reheat mode, the humidification mode or the dehumidification mode; determining the cooling system is operating in the compressor mode, such that the cooling system is not operating in the pump refrigerant economization mode; determining a plurality of parameters are in a predefined operational space; determining the cooling system is at steady-state; determining an average of qualified values of a first parameter of the cooling system as a result of (i) the plurality of parameters being in the predefined operational space, and (ii) the cooling system operating in the cooling mode and the compressor mode and being at steady-state, wherein the plurality of parameters do not include the first parameter; based on the average of qualified values, determining whether a predefined criterion is satisfied for a degradation symptom of the cooling system; generating a degradation evaluation value to indicate whether the predefined criterion is satisfied; and based on the degradation evaluation value, generating an alarm signal or performing a countermeasure.
19. The method of claim 18 , further comprising:
iteratively determining the average of qualified values;
incrementing a counter subsequent to each of the iterative determinations of the average of qualified values;
determining if a value of the counter is greater than or equal to a predetermined threshold;
generating the degradation evaluation value if the value of the counter is greater than or equal to the predetermined threshold; and
refraining from generating the degradation evaluation value if the value of the counter is less than the predetermined threshold.
20. The method of claim 19 , further comprising, if the counter is greater than or equal to the predetermined threshold:
increasing a bin threshold; and
increasing the value of the counter,
wherein the determining of whether the predefined criterion is satisfied includes determining whether the first parameter is greater than a maximum of (i) a product of the bin threshold and an average of previously qualified versions of the first parameter, and (ii) a sum of a constant and the average of qualified values of the first parameter.
21. The method of claim 20 , wherein:
the plurality of parameters include a compressor loading percentage and a compressor pressure differential; and
the first parameter is an open percentage of a first expansion valve of a first cooling circuit or an open percentage of a second expansion valve of a second cooling circuit.
22. The method of claim 18 , further comprising:
iteratively determining an average deviation associated with the first parameter;
incrementing a counter subsequent to each of the iterative determinations of the average deviation;
determining if a value of the counter is greater than or equal to a predetermined threshold
generating the degradation evaluation value if the value of the counter is greater than or equal to the predetermined threshold; and
refraining from generating the degradation evaluation value if the value of the counter is less than the predetermined threshold.
23. The method of claim 22 , further comprising, if the counter is greater than or equal to the predetermined threshold:
increasing a bin threshold; and
increasing the value of the counter,
wherein the determining of whether the predefined criterion is satisfied includes determining whether the first parameter is greater than a maximum of (i) a product of the bin threshold and an average of previously measured versions of the first parameter, and (ii) a sum of a constant and the average of qualified values of the first parameter.
24. The method of claim 18 , further comprising:
iteratively evaluating the criterion to determine if the degradation symptom exists for the cooling system;
subsequent to each of the iteratively performed evaluations, generating a respective degradation evaluation value to indicate whether the criterion is satisfied;
incrementing a counter for each of the degradation evaluation values indicating that the criterion is satisfied; and
determining a value of the counter is greater than or equal to a predetermined threshold and generating the alarm signal or performing the countermeasure as a result of the value of the counter being greater than or equal to the predetermined threshold.
25. The method of claim 18 , further comprising controlling one or more cooling circuits based on the degradation evaluation value, wherein each of the one or more cooling circuits includes a respective compressor, condenser, expansion valve, and evaporator.
26. The method of claim 18 , further comprising:
the average of qualified values is iteratively determined and includes combining and averaging a currently collected qualified value with historically collected qualified values;
each of the qualified values refers to a parameter that satisfies a rule while a plurality of predetermined conditions exist;
incrementing a bin counter each time one of the qualified values is determined to be qualified; and
determining the bin counter has exceeded a predetermined number,
wherein the predefined criterion is determined to be satisfied as a result of the determining that the bin counter has exceeded the predetermined number.