Lubrication system for a compressor
A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system includes a refrigerant circuit configured to flow a refrigerant therethrough, a sump configured to direct a lubricant to a compressor, an ejector configured to direct the lubricant from the refrigerant circuit to the sump, and an expansion device configured to reduce a pressure of the refrigerant directed through the refrigerant circuit. The HVAC&R system further includes a controller configured to instruct the expansion device to adjust to a first position to enable the ejector to direct lubricant from the refrigerant circuit to the sump at a first target flow rate in a first mode, and the controller is configured to instruct the expansion device to adjust to a second position to enable the ejector to direct lubricant from the refrigerant circuit to the sump at a second target flow rate in a second mode.
1 . A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system, comprising:
a refrigerant circuit configured to flow a refrigerant therethrough;
a condenser positioned along the refrigerant circuit and configured to receive the refrigerant from a compressor positioned along the refrigerant circuit;
a sump configured to direct a lubricant to the compressor positioned along the refrigerant circuit, wherein the sump and the condenser are separate from one another, and wherein the lubricant directed to the compressor and the refrigerant directed through the refrigerant circuit are different fluids;
an ejector configured to direct the lubricant from the refrigerant circuit to the sump;
an expansion device positioned along the refrigerant circuit and configured to reduce a pressure of the refrigerant directed through at least a portion of the refrigerant circuit; and
a controller configured to adjust operation of the HVAC&R system between a first mode and a second mode, wherein the controller is configured to instruct the expansion device to adjust to a first position to enable the ejector to direct the lubricant from the refrigerant circuit to the sump at a first target flow rate in the first mode, and wherein the controller is configured to instruct the expansion device to adjust to a second position to enable the ejector to direct the lubricant from the refrigerant circuit to the sump at a second target flow rate in the second mode.
2 . The HVAC&R system of claim 1 , wherein the second target flow rate is greater than the first target flow rate.
3 . The HVAC&R system of claim 2 , comprising an evaporator positioned along the refrigerant circuit and configured to receive the refrigerant from the expansion device, wherein an evaporating temperature of the refrigerant in the evaporator is a first evaporating temperature in the first mode, wherein the evaporating temperature of the refrigerant in the evaporator is a second evaporating temperature in the second mode, and wherein the second evaporating temperature is less than the first evaporating temperature.
4 . The HVAC&R system of claim 1 , wherein the ejector is configured to draw liquid from an evaporator positioned along the refrigerant circuit and direct the liquid to the sump.
5 . The HVAC&R system of claim 1 , wherein the controller is configured to transition the HVAC&R system between operating in the first mode and operating in the second mode based on feedback indicative of an operating parameter of the HVAC&R system.
6 . The HVAC&R system of claim 5 , wherein the sump comprises a liquid level indicator configured to provide feedback to the controller indicative of an amount of liquid in the sump, and wherein the controller is configured to adjust the HVAC&R system to operate in the second mode in response to feedback indicative of the amount of liquid in the sump being below a threshold amount.
7 . The HVAC&R system of claim 1 , wherein the lubricant comprises oil.
8 . The HVAC&R system of claim 1 , wherein the first mode corresponds to a normal operating mode of the HVAC&R system and the second mode corresponds to a lubricant return mode of the HVAC&R system, and wherein the ejector, during operation of the HVAC&R system, directs a greater amount of the lubricant into the sump in the lubricant return mode relative to the normal operating mode.
9 . A heating, ventilation, air conditioning, and/or refrigeration (HVAC&R) system, comprising:
a refrigerant circuit configured to flow a refrigerant therethrough;
a sump configured to direct a lubricant to a compressor positioned along the refrigerant circuit, wherein the lubricant and the refrigerant are different fluids;
an ejector configured to direct the lubricant from the refrigerant circuit to the sump, wherein the ejector comprises an inlet fluidly coupled to a condenser positioned along the refrigerant circuit and an outlet fluidly coupled to the sump;
an expansion device positioned along the refrigerant circuit and configured to reduce a pressure of the refrigerant directed through at least a portion of the refrigerant circuit; and
a controller configured to adjust operation of the HVAC&R system between a first mode and a second mode, wherein the controller is configured to instruct the expansion device to adjust to a first position to cause the ejector to direct the lubricant from the refrigerant circuit to the sump at a first target flow rate in the first mode, and the controller is configured to instruct the expansion device to adjust to a second position to cause the ejector to direct the lubricant from the refrigerant circuit to the sump at a second target flow rate in the second mode.
10 . The HVAC&R system of claim 1 , wherein the ejector is configured to receive a first mixture of the refrigerant and the lubricant from the condenser via an inlet of the ejector and to discharge a second mixture of the refrigerant and the lubricant toward the sump via an outlet of the ejector.
11 . The HVAC&R system of claim 3 , wherein a concentration of the lubricant within the evaporator is a first concentration in the first mode, wherein the concentration of the lubricant within the evaporator is a second concentration in the second mode, and wherein the second concentration is greater than the first concentration based on the second evaporating temperature of the refrigerant in the second mode being less than the first evaporating temperature of the refrigerant in the first mode.
12 . The HVAC&R system of claim 9 , wherein the inlet is directly coupled to the condenser and the outlet is directly coupled to the sump.