Abstract: An air conditioning service system includes an oil receptacle configured to store an oil, a solenoid valve configured to selectively allow the oil to flow from the oil receptacle into an oil injection line, a coupling port in fluid communication with the oil receptacle through the oil injection line when the solenoid valve is in an open condition, and a flow control valve with an inlet and an outlet. The inlet is in fluid communication with the oil receptacle when the solenoid valve is in the open condition, and the outlet in fluid communication with the oil injection line when the solenoid valve is in the open condition. The flow control valve is configured such that, for a given pressure difference between the inlet and the outlet, the oil flows from through the flow control valve at a flow rate that is independent of a viscosity of the oil.

Abstract: An air conditioning service system includes a plurality of conduits and voids defining a total refrigerant receiving volume of the air conditioning service system, a pressure transducer configured to sense a pressure at a first location in the plurality of conduits and voids, a compressor operably connected to the plurality of conduits and voids, and a controller. The controller determines a quantity of refrigerant recovered from a refrigeration system by obtaining a first pressure signal from the pressure transducer corresponding to a first pressure at the first location, operating the compressor to recover the refrigerant from the refrigeration system after the first pressure is sensed, obtaining a second pressure signal from the pressure transducer corresponding to a second pressure at the first location after operating the compressor, and determining an amount of refrigerant recovered from the refrigeration system based on the first pressure signal an the second pressure signal.

Abstract: An air conditioning service system includes an oil receptacle, a coupling port in fluid communication with the oil receptacle through an oil injection line, a solenoid valve configured to selectively allow the oil to flow from the oil receptacle into the oil injection line, a memory including program instructions stored therein, and a controller operably connected to the solenoid valve and the memory. The controller is configured to execute the program instructions to obtain at least one viscosity signal associated with a viscosity of the oil, obtain a volume signal indicative of an amount of oil to be charged, determine a time period based upon the obtained at least one viscosity signal and the obtained volume signal, control the solenoid valve to an open condition, and control the solenoid valve to a closed condition after the determined time period has passed since opening of the solenoid valve.

Abstract: A refrigerant service system comprises a compressor having a compressor inlet and a compressor outlet, an inlet conduit, an outlet conduit, and an accumulator including an outer housing shell and an inner housing shell disposed within the outer housing shell. A first chamber is defined in the accumulator between the inner housing shell and the outer housing shell, the first chamber being configured to receive refrigerant from the inlet conduit and discharge the refrigerant to the compressor inlet. A second chamber is defined in the accumulator within the inner housing shell, the second chamber being configured to receive the refrigerant from the compressor outlet and discharge the refrigerant to the outlet conduit. Heat is transferred from the refrigerant in the second chamber through the inner shell to the refrigerant in the first chamber.

Abstract: An air conditioning service system includes a refrigerant storage vessel, a charging subsystem fluidly connected to the refrigerant storage vessel and configured to connect to a refrigeration circuit to transfer refrigerant from the refrigerant storage vessel to the refrigeration circuit, a first pressure transducer configured to sense a first pressure in the refrigerant storage vessel, a first valve configured to control a flow of ambient air between the refrigerant storage vessel and the atmosphere, and a controller operably connected to the first pressure transducer and the first valve. The controller includes a memory and a processor configured to execute program instructions stored in the memory to operate the first valve to admit air into the refrigerant storage vessel based on the sensed first pressure, and to operate the charging subsystem to fluidly connect the refrigerant storage vessel to the refrigeration circuit.

Abstract: A compressor system for an air conditioning service system includes a compressor having a compressor case and a compressor head, an inlet, an outlet, a low side passage fluidly connecting the inlet to the compressor head, and a high side passage fluidly connecting the outlet to the compressor head. A low side return passage fluidly connects the compressor case with the low side passage and a first valve is positioned at least partially in the low side return passage and configured to control flow in the low side return passage.

Abstract: An air conditioning service system includes a discharge unit including a discharge vessel, a vacuum pump fluidly connected to the discharge vessel, a scale configured to sense a weight of the discharge unit, a first valve arranged in an input line configured to fluidly connect the discharge vessel to an air conditioning system, and a vent valve arranged in a vent line and configured to fluidly connect the discharge vessel to the atmosphere. A controller operates the vacuum pump to evacuate the discharge vessel, obtains an evacuated weight of the discharge unit, operates the first valve to open to fill the discharge vessel with refrigerant, obtains a filled weight of the discharge unit, operates the vent valve to vent refrigerant from the discharge vessel, obtains a vented weight of the discharge unit, and determines a mass of refrigerant vented based upon the stored evacuated, filled, and vented weights.

Abstract: An air conditioning service system includes an inlet port configured to connect to an air conditioning system to receive refrigerant, a discharge circuit, a pressure transducer, and a controller. The discharge circuit includes a plurality of discharge lines arranged in parallel with one another, each of the plurality of discharge lines fluidly connecting the inlet port to the atmosphere through an associated orifice to vent the refrigerant to atmosphere, and a plurality of discharge valves, each of which is configured to open and close an associated one of the plurality of discharge lines. The controller is configured to obtain the pressure at the inlet port and determine a theoretical mass flow rate through each of the plurality of discharge lines based upon the pressure and the cross-sectional area of the associated orifice, and to operate selected ones of the discharge valves based upon the determined theoretical mass flow rates.

Abstract: A refrigerant service system according to the disclosure includes an inlet port configured to connect to an air conditioning system, a recovery valve fluidly connected to the inlet port, an accumulator fluidly connected to the recovery solenoid valve and including a pressure transducer configured to generate an electronic signal corresponding to a pressure in the accumulator, and a controller. The controller is configured to determine a target pressure for the accumulator based upon a condition of the refrigerant, obtain a current pressure in the accumulator from the pressure transducer, and to operate the recovery valve based upon the accumulator target pressure to control flow of refrigerant from the air conditioning system to the accumulator based upon the obtained current pressure and the determined target pressure for the accumulator.

Abstract: An air conditioning service system includes an accumulator defining an accumulator chamber, a pressure transducer operably connected to the accumulator chamber, a drain valve operably connected to the accumulator chamber, and a controller operably connected to the pressure transducer and the drain valve. The controller includes a processor configured to execute program instructions stored in a memory to determine a volume of liquid drained from the accumulator by: determining a volumetric flow rate of liquid through the drain valve by controlling the drain valve with the controller to an open position for a predetermined period of time; detecting an increased rate of pressure reduction while the drain valve is open; and determining an amount of liquid drained through the drain valve based upon the volumetric flow rate and a total time elapsed between opening the drain valve and the increased rate of pressure reduction.

Abstract: A refrigerant recovery system includes a first oil separator including a chamber configured to receive refrigerant from an air conditioning system, a heat exchanger disposed within the first oil separator, and a compressor fluidly connected to the chamber and the heat exchanger. A first valve is disposed in a first flow line that is fluidly connected between an inlet of the first oil separator and a source of refrigerant and a second valve is disposed in a second flow line that fluidly connects the compressor and the heat exchanger. A controller is configured to open the first valve to enable refrigerant to pass into the chamber of the first oil separator, open the second valve so that a flow loop for refrigerant is formed between the heat exchanger and the compressor, activate the compressor to heat the refrigerant flowing through the flow loop, and subsequently commence a refrigerant recovery operation.

Abstract: A method of operating a refrigerant service system to charge an air conditioning circuit includes pre-charging a predetermined pre-charge quantity of refrigerant into the air conditioning circuit, determining an average temperature in the air conditioning circuit based upon a pressure in the air conditioning circuit after pre-charging the air conditioning circuit, determining a charge compensation value based upon the determined average temperature in the air conditioning circuit, and charging the air conditioning circuit with a quantity of refrigerant based upon the charge compensation value.

Abstract: An air conditioning service system includes an oil receptacle, a coupling port in fluid communication with the oil receptacle through an oil injection line, a solenoid valve configured to selectively allow the oil to flow from the oil receptacle into the oil injection line, a memory including program instructions stored therein, and a controller operably connected to the solenoid valve and the memory. The controller is configured to execute the program instructions to obtain at least one viscosity signal associated with a viscosity of the oil, obtain a volume signal indicative of an amount of oil to be charged, determine a time period based upon the obtained at least one viscosity signal and the obtained volume signal, control the solenoid valve to an open condition, and control the solenoid valve to a closed condition after the determined time period has passed since opening of the solenoid valve.

Abstract: An air conditioning service system includes a plurality of conduits and voids defining a total refrigerant receiving volume of the air conditioning service system, a pressure transducer configured to sense a pressure at a first location in the plurality of conduits and voids, a compressor operably connected to the plurality of conduits and voids, and a controller. The controller determines a quantity of refrigerant recovered from a refrigeration system by obtaining a first pressure signal from the pressure transducer corresponding to a first pressure at the first location, operating the compressor to recover the refrigerant from the refrigeration system after the first pressure is sensed, obtaining a second pressure signal from the pressure transducer corresponding to a second pressure at the first location after operating the compressor, and determining an amount of refrigerant recovered from the refrigeration system based on the first pressure signal an the second pressure signal.

Abstract: An air conditioning service system includes an accumulator defining an accumulator chamber, a pressure transducer operably connected to the accumulator chamber, a drain valve operably connected to the accumulator chamber, and a controller operably connected to the pressure transducer and the drain valve. The controller includes a processor configured to execute program instructions stored in a memory to determine a volume of liquid drained from the accumulator by: determining a volumetric flow rate of liquid through the drain valve by controlling the drain valve with the controller to an open position for a predetermined period of time; detecting an increased rate of pressure reduction while the drain valve is open; and determining an amount of liquid drained through the drain valve based upon the volumetric flow rate and a total time elapsed between opening the drain valve and the increased rate of pressure reduction.

Abstract: An air conditioning service system includes a refrigerant storage vessel, a charging subsystem fluidly connected to the refrigerant storage vessel and configured to connect to a refrigeration circuit to transfer refrigerant from the refrigerant storage vessel to the refrigeration circuit, a first pressure transducer configured to sense a first pressure in the refrigerant storage vessel, a first valve configured to control a flow of ambient air between the refrigerant storage vessel and the atmosphere, and a controller operably connected to the first pressure transducer and the first valve. The controller includes a memory and a processor configured to execute program instructions stored in the memory to operate the first valve to admit air into the refrigerant storage vessel based on the sensed first pressure, and to operate the charging subsystem to fluidly connect the refrigerant storage vessel to the refrigeration circuit.

Abstract: An air conditioning service system includes a discharge unit including a discharge vessel, a vacuum pump fluidly connected to the discharge vessel, a scale configured to sense a weight of the discharge unit, a first valve arranged in an input line configured to fluidly connect the discharge vessel to an air conditioning system, and a vent valve arranged in a vent line and configured to fluidly connect the discharge vessel to the atmosphere. A controller operates the vacuum pump to evacuate the discharge vessel, obtains an evacuated weight of the discharge unit, operates the first valve to open to fill the discharge vessel with refrigerant, obtains a filled weight of the discharge unit, operates the vent valve to vent refrigerant from the discharge vessel, obtains a vented weight of the discharge unit, and determines a mass of refrigerant vented based upon the stored evacuated, filled, and vented weights.

Abstract: An air conditioning service system includes an inlet port configured to connect to an air conditioning system to receive refrigerant, a discharge circuit, a pressure transducer, and a controller. The discharge circuit includes a plurality of discharge lines arranged in parallel with one another, each of the plurality of discharge lines fluidly connecting the inlet port to the atmosphere through an associated orifice to vent the refrigerant to atmosphere, and a plurality of discharge valves, each of which is configured to open and close an associated one of the plurality of discharge lines. The controller is configured to obtain the pressure at the inlet port and determine a theoretical mass flow rate through each of the plurality of discharge lines based upon the pressure and the cross-sectional area of the associated orifice, and to operate selected ones of the discharge valves based upon the determined theoretical mass flow rates.

Abstract: An air conditioning service system includes an oil receptacle configured to store an oil, a solenoid valve configured to selectively allow the oil to flow from the oil receptacle into an oil injection line, a coupling port in fluid communication with the oil receptacle through the oil injection line when the solenoid valve is in an open condition, and a flow control valve with an inlet and an outlet. The inlet is in fluid communication with the oil receptacle when the solenoid valve is in the open condition, and the outlet in fluid communication with the oil injection line when the solenoid valve is in the open condition. The flow control valve is configured such that, for a given pressure difference between the inlet and the outlet, the oil flows from through the flow control valve at a flow rate that is independent of a viscosity of the oil.

Abstract: A refrigerant recovery system includes a first oil separator including a chamber configured to receive refrigerant from an air conditioning system, a heat exchanger disposed within the first oil separator, and a compressor fluidly connected to the chamber and the heat exchanger. A first valve is disposed in a first flow line that is fluidly connected between an inlet of the first oil separator and a source of refrigerant and a second valve is disposed in a second flow line that fluidly connects the compressor and the heat exchanger. A controller is configured to open the first valve to enable refrigerant to pass into the chamber of the first oil separator, open the second valve so that a flow loop for refrigerant is formed between the heat exchanger and the compressor, activate the compressor to heat the refrigerant flowing through the flow loop, and subsequently commence a refrigerant recovery operation.