A system for measuring oil circulation ratio in a vapor-compression refrigeration system (VCRS) is provided. The system may include an oil separator configured to receive the refrigerant and oil flow from the low-pressure line of the VCRS and output a oil flow and a refrigerant flow. The system may further include an oil collector configured to receive the separated oil flow provided by the oil separator. A valve may control an oil flow from the oil collector to the low-pressure line. A level sensor may measure oil level in the oil collector. The system may close, in response to the oil being at or less than a first level, the valve to collect oil in the oil collector. The system may open, in response to the oil being at or greater than a second level, the valve to release oil from the oil collector to the low-pressure line.

A method of detecting electrical failure in a refrigeration system is provided. The method includes determining whether a present superheat of the refrigeration system is between a maximum superheat and a minimum superheat for the refrigeration system, the maximum superheat and the minimum superheat defining a normal operating range. The method also includes detecting an electrical property of an expansion valve assembly of the refrigeration system responsive to the superheat being outside the normal operating range. The method further includes determining whether the expansion valve assembly as experienced an electrical failure based on at least the electrical property. A signal indicating that the expansion valve has experienced an electrical failure is generated based on a determination that the expansion valve assembly has experienced the electrical failure.

An electronic expansion valve and a thermal management assembly. The electronic expansion valve has a valve port and a valve core. A valve body includes a first flow portion, a second flow portion, a first cavity and a second cavity. The first flow portion comprises a first connection section and a first subsection, and the first subsection is directly in communication with the first cavity. The second flow portion comprises a second connection section and a second subsection, and the second subsection is directly in communication with the second cavity. In a clockwise direction, an angle formed between at least one of the center line of the first subsection and the center line of the second subsection and the center line of the valve core is an acute angle.

A thermal management system includes an open circuit refrigeration circuit that has a refrigerant fluid flow path, with the refrigerant fluid flow path including a receiver configured to store a refrigerant fluid, a first control device configured to receive refrigerant from the receiver, a liquid separator, and an evaporator configured to extract heat from a heat load that contacts the evaporator, with the evaporator coupled to the first control device and the liquid separator. The system includes a pump having an inlet and an outlet, with the outlet of the pump coupled to the liquid side outlet of the liquid separator and a second control device that is coupled to an exhaust line, that is coupled to the vapor side outlet of the liquid separator through the second control device. In operation, the evaporator in the open circuit refrigeration circuit would be coupled to a heat load.

Systems and methods for disrupting a flow of refrigerant within a heat exchanger assembly. One embodiment provides a method that includes receiving, with a controller, a first signal from a first sensor, the first signal indicative of a pressure of the refrigerant flowing through the heat exchanger. The method includes setting, with the controller, an operating frequency of a valve based on the first signal. The operating frequency includes a rate at which the valve actuates between a first valve position that sets a first refrigerant flow rate through the heat exchanger and a second valve position that sets a second refrigerant flow rate through the heat exchanger. The method includes controlling, with the controller, operation of a solenoid to actuate the valve at the operating frequency.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a first portion of a refrigeration system within a building; and an isolation module configured to selectively open and close an isolation valve of the refrigeration system and to, via the isolation valve, maintain the amount of refrigerant within the first portion within the building below a predetermined amount of the refrigerant.

A controller for a refrigeration system includes a processing circuit having one or more processors and memory. The processing circuit is configured to calculate a superheat of a gas refrigerant exiting a first side of a subcooler based on a measured temperature and a measured pressure of the gas refrigerant and compare the calculated superheat to a superheat threshold. In response to a determination that the calculated superheat is less than the superheat threshold, the processing circuit closes an expansion valve to restrict a flow of the gas refrigerant through a second side of the subcooler. In response to a determination that the calculated superheat is equal to or greater than the superheat threshold, the processing circuit operates the expansion valve to drive a temperature of a subcooled liquid refrigerant exiting the second side of the subcooler to a subcooled liquid temperature setpoint.

Systems and methods for disrupting a flow of refrigerant within a heat exchanger assembly. One embodiment provides a method that includes receiving, with a controller, a first signal from a first sensor, the first signal indicative of a pressure of the refrigerant flowing through the heat exchanger. The method includes setting, with the controller, an operating frequency of a valve based on the first signal. The operating frequency includes a rate at which the valve actuates between a first valve position that sets a first refrigerant flow rate through the heat exchanger and a second valve position that sets a second refrigerant flow rate through the heat exchanger. The method includes controlling, with the controller, operation of a solenoid to actuate the valve at the operating frequency.

A refrigerant control system includes: a charge module configured to determine an amount of refrigerant that is present within a refrigeration system of a building; a leak module configured to diagnose that a leak is present in the refrigeration system based on the amount of refrigerant; and at least one module configured to take at least one remedial action in response to the diagnosis that the leak is present in the refrigeration system.

A thermal management system includes an open circuit refrigeration circuit that has a refrigerant fluid flow path, with the refrigerant fluid flow path including a receiver configured to store a refrigerant fluid, a first control device configured to receive refrigerant from the receiver, a liquid separator, and an evaporator configured to extract heat from a heat load that contacts the evaporator, with the evaporator coupled to the first control device and the liquid separator. The system includes a pump having an inlet and an outlet, with the outlet of the pump coupled to the liquid side outlet of the liquid separator and a second control device that is coupled to an exhaust line, that is coupled to the vapor side outlet of the liquid separator through the second control device. In operation, the evaporator in the open circuit refrigeration circuit would be coupled to a heat load.