Compressor floodback protection system
A climate-control system may include a compressor, a condenser, an evaporator, a first sensor, a second sensor, a third sensor, and a control module. The compressor may include a motor and a compression mechanism. The condenser receives compressed working fluid from the compressor. The evaporator is in fluid communication with the compressor and disposed downstream of the condenser and upstream of the compressor. The first sensor may detect an electrical operating parameter of the motor. The second sensor may detect a discharge temperature of working fluid discharged by the compression mechanism. The third sensor may detect a suction temperature of working fluid between the evaporator and the compression mechanism. The control module is in communication with the first, second and third sensors and may determine whether a refrigerant floodback condition is occurring in the compressor based on data received from the first, second and third sensors.
1. A climate-control system comprising:
a compressor having a motor and a compression mechanism;
a condenser receiving compressed working fluid from the compressor;
an evaporator in fluid communication with the compressor and disposed downstream of the condenser and upstream of the compressor;
a first sensor detecting an electrical operating parameter of the motor;
a second sensor detecting a discharge temperature of working fluid discharged by the compression mechanism;
a third sensor detecting a suction temperature of working fluid between the evaporator and the compression mechanism; and
a control module in communication with the first, second and third sensors and determining whether a refrigerant floodback condition is occurring based on the electrical operating parameter of the motor detected by the first sensor, the discharge temperature detected by the second sensor, and the suction temperature detected by the third sensor.
2. The climate-control system of claim 1 , wherein the control module determines whether the floodback condition is occurring based on a comparison between a calculated discharge-superheat-value and a predetermined discharge-superheat-threshold.
3. The climate-control system of claim 2 , wherein the only measured data used to detect the refrigerant floodback condition is data measured by the first, second and third sensors.
4. The climate-control system of claim 1 , wherein a severity of the refrigerant floodback condition is determined based on a level of oil dilution in an oil sump of the compressor.
5. The climate-control system of claim 4 , wherein the control module issues a fault warning or a fault trip in response to determining the severity of the refrigerant floodback condition.
6. The climate-control system of claim 4 , wherein the level of oil dilution is calculated using the equation:
log
10
(
P
)
=
a
1
+
a
2
T
+
a
3
T
2
+
log
10
(
ω
)
(
a
4
+
a
5
T
+
a
6
T
2
)
+
log
10
2
(
ω
)
(
a
7
+
a
8
T
+
a
9
T
2
)
,
wherein P is a pressure of gas immediately above an oil level in the oil sump within the compressor; wherein ω is the level of oil dilution; wherein T is a temperature of the oil in the oil sump; and wherein a 1 through a 9 are constants.
7. The climate-control system of claim 6 , wherein the severity of the refrigerant floodback condition is determined based on a comparison of the level of oil dilution and a dilution limit value.
8. The climate-control system of claim 7 , wherein the dilution limit value is determined based on a calculated condensing temperature and a calculated evaporating temperature.
9. The climate-control system of claim 8 , wherein the pressure (P) of gas immediately above the oil level is determined based on the suction temperature measured by the third sensor.
10. The climate-control system of claim 1 , wherein the compressor is a low-side scroll compressor.