A transport refrigeration system includes a compressor, a heat rejection heat exchanger, a flash tank, an expansion device and a heat absorption heat exchanger arranged in a serial refrigerant flow order to circulate a refrigerant; a controller configured to: determine a presence of at least one condition of the transport refrigeration system; and initiate a low refrigerant charge detection process in response to detecting the presence of the at least one condition of the transport refrigeration system.

Systems and methods for controlling pressure in a CO.sub.2 refrigeration system are provided. The pressure control system includes a pressure sensor, a gas bypass valve, a parallel compressor, and a controller. The pressure sensor is configured to measure a pressure within a receiving tank of the CO.sub.2 refrigeration system. The gas bypass valve is fluidly connected with an outlet of the receiving tank and arranged in series with a compressor of the CO.sub.2 refrigeration system. The parallel compressor is fluidly connected with the outlet of the receiving tank and arranged in parallel with both the gas bypass valve and the compressor of the CO.sub.2 refrigeration system. The controller is configured to receive a pressure measurement from the pressure sensor and operate both the gas bypass valve and the parallel compressor, in response to the pressure measurement, to control the pressure within the receiving tank.

A system includes a pressure exchanger (PX). The PX is coupled to a motor that controls an operating speed of the PX. The system further includes a condenser. An outlet of the condenser is fluidly coupled to a first inlet of the PX. The system further includes a pressure gauge. The pressure gauge is configured to provide first pressure data. The first pressure data is indicative of a pressure of a fluid of the condenser. The system further includes a first controller configured to cause the motor to adjust the operating speed of the PX. The first controller causes the motor to adjust the operating speed of the PX based on the first pressure data.

The propagation of a disproportionation reaction of a refrigerant is suppressed. Disclosed is a method that uses a composition as a refrigerant in a compressor, in which the composition includes one or more compounds selected from the group of ethylene-based fluoroolefins, 2,3,3,3-tetrafluoropropene, and 1,3,3,3-tetrafluoropropene, and the flow rate of the refrigerant flowing through a discharge pipe of the compressor under a predetermined high-pressure condition is greater than or equal to 1 m/s.

A system includes a pressure exchanger (PX) configured to receive a first fluid at a first pressure and a second fluid at a second pressure and exchange pressure between the first fluid and the second fluid. The system further includes a condenser configured to provide corresponding thermal energy from the first fluid to a corresponding environment. The system further includes a first ejector to receive a first gas and increase pressure of the first gas to form the second fluid at the second pressure. The first ejector is further to provide the second fluid at the second pressure to the PX.

A system includes a pressure exchanger (PX) configured to receive a first fluid at a first pressure, receive a second fluid at a second pressure, and exchange pressure between the first fluid and the second fluid. The first fluid is to exit the PX at a third pressure and the second fluid is to exit the PX at a fourth pressure. The system further includes a first heat exchanger configured to provide the first fluid to the PX and provide corresponding thermal energy from the first fluid to a third fluid. The system further includes a turbine configured to receive the third fluid output from the first heat exchanger. The turbine is further configured to convert corresponding thermal energy of the third fluid into kinetic energy.

A fluid handling system includes a pressure exchanger (PX) configured to receive a first fluid at a first pressure and a second fluid at a second pressure and exchange pressure between the first fluid and the second fluid. The system further includes a condenser configured to provide corresponding thermal energy from the first fluid to a corresponding environment. The system further includes a receiver to receive the first fluid output by the PX. The receiver forms a chamber to separate the first fluid into a first gas and a first liquid. The system further includes a first booster to increase pressure of a portion of the first gas to form the second fluid at the second pressure and provide the second fluid at the second pressure to the PX.

A controller of a heating, ventilation, and air conditioning (HVAC) system, the controller comprising instructions that cause the controller to determine an air flowrate of an air blower of the HVAC system and calculate a threshold value based on a minimum required air flowrate. The controller further comprises instructions that cause the controller to send a notification to an operator of the HVAC system indicating that the air flowrate of the air blower is less than the threshold value in response to determining that the air flowrate of the air blower is less than the threshold value and shut down the HVAC system such that the refrigerant is no longer circulated by the componentry of the HVAC system in response to determining that the air flowrate of the air blower is less than the minimum required air flowrate.

A cooling system includes: a local cooler that is positioned near a server serving as a heat source and that evaporates a refrigerant by directly receiving heat from the server to generate a gas-phase refrigerant; a compressor that compresses the gas-phase refrigerant; an outdoor unit that condenses the gas-phase refrigerant supplied from the compressor by dissipating heat from the gas-phase refrigerant; an expansion valve that depressurizes the refrigerant supplied from the outdoor unit and sends the refrigerant to the local cooler; a pair of detectors that are respectively provided at an inlet side and an outlet side of the compressor and detect a state of the gas-phase refrigerant supplied from the local cooler; and a proportional control valve and a high-speed on-off valve that are operated based on a refrigerant state ratio calculated from a detection value of the detectors.

A dynamic receiver is included in parallel to an expander of a heating, ventilation, air conditioning, and refrigeration (HVACR) system. The dynamic receiver allows control of the refrigerant charge of the HVACR system to respond to different operating conditions. The dynamic receiver can be filled or emptied in response to the subcooling observed in the HVACR system compared to desired subcooling for various operating modes. The flow through an expander of the HVACR system can be controlled to account for the mass flow rate through an outlet valve of the dynamic receiver when the dynamic receiver is emptied, preventing or reducing instability or effects on system parameters such as the suction superheat.