A refrigeration system includes a receiver, a gas bypass valve, a parallel compressor, and a controller. The gas bypass valve and the parallel compressor are fluidly coupled to an outlet of the receiver in parallel and configured to control a pressure of a gas refrigerant in the receiver. The controller is configured to switch from operating the gas bypass valve to operating the parallel compressor to control the pressure of the gas refrigerant in the receiver in response to a value of a process variable crossing a switchover setpoint. The value of the process variable depends on an amount of the gas refrigerant produced by the refrigeration system. The controller is configured to automatically adjust the switchover setpoint in response to the amount of the gas refrigerant produced by the refrigeration system being insufficient to sustain operation of the parallel compressor.

A hybrid multi-air conditioning system with no receiver is provided for optimal valve control. The hybrid multi-air conditioning system includes: a hot-water unit for exchanging heat between refrigerant and water; at least one indoor unit installed indoors and comprising an indoor heat exchanger and an indoor unit expansion valve; and an outdoor unit connected to the indoor unit and the hot-water unit via a refrigerant pipeline and comprising an outdoor heat exchanger, a compressor, and an outdoor unit expansion valve, wherein, when an abnormal refrigerant enters either the at least one indoor unit or the outdoor unit according to an operation mode, the abnormal refrigerant is shut off from the hot-water unit and the at least one indoor unit or the outdoor unit which operates as a condenser. Accordingly, the hybrid multi-air conditioning system improves heat exchange efficiency via direct heat transfer between refrigerant and water by having a coil wound on the water tank to transfer heat between refrigerant and water.

A cooling system including a vaporizer configured to absorb heat due to a liquid-phase refrigerant being vaporized, a condenser configured to discharge heat due to a refrigerant in a gaseous phase state being liquefied, a resistance body provided in a middle of a pipe passage ranging from the vaporizer to the condenser and applying a resistance to the refrigerant, state detection sensors provided in the pipe passage on an upstream and downstream sides of the resistance body and detecting a state of the refrigerant flowing through each side inside the pipe passage, and a flow rate controller configured to detect droplets in the refrigerant flowing through the pipe passage on the basis of a difference between detection values of the state detection sensors which are detected on the upstream and downstream sides of the resistance body, and controls a flow rate of the refrigerant on the basis of detection results.

The determination of the refrigerant amount is facilitated. A refrigerant amount inference apparatus infers a refrigerant amount in an air conditioner in which a compressor, a heat source side heat exchanger, a supercooling heat exchanger, a pressure reducing valve, and a use side heat exchanger are connected to piping. The supercooling heat exchanger is a heat exchanger that exchanges heat between refrigerant that passes through a supercooling bypass expansion valve provided in a bypass circuit and refrigerant in a mainstream circuit. The bypass circuit is connected to piping on a suction side of the compressor from a position between the heat source side heat exchanger and the supercooling heat exchanger or a position between the pressure reducing valve and the supercooling heat exchanger. The refrigerant amount inference apparatus includes an acquiring unit configured to acquire a state of refrigerant in first piping provided between the pressure reducing valve and the supercooling heat exchanger and an operation amount related to the state of the refrigerant in the first piping, and a training unit configured to perform training by associating the state of the refrigerant in the first piping and the operation amount related to the state of the refrigerant in the first piping with a refrigerant amount.

A vapor cycle system for cooling components includes a refrigeration circuit through which a mass of a refrigerant flows. The refrigeration circuit, in turn, includes a compressor, a first condenser, a second condenser fluidly coupled to the first condenser in series or in parallel, an expansion valve, and an evaporator. Furthermore, the system includes a refrigerant charge control device configured to increase or decrease the mass of the refrigerant flowing through the refrigeration circuit.

A dehumidification system includes a compressor, a primary evaporator, a primary condenser, a secondary evaporator, a secondary condenser, a plurality of posts, and a drain pan. The secondary evaporator receives an inlet airflow and outputs a first airflow to the primary evaporator. The primary evaporator receives the first airflow and outputs a second airflow to the secondary condenser. The drain pan captures water removed from the first airflow by the primary evaporator. The secondary condenser receives the second airflow and outputs a third airflow to the primary condenser. The primary condenser receives the third airflow and outputs a fourth airflow. The compressor receives a flow of refrigerant from the primary evaporator and provides the flow of refrigerant to the primary condenser.

Systems and methods for implementing ejector refrigeration cycles with cascaded evaporation stages that utilize a pump to optimize operation of the ejector and eliminate the need for a compressor between the evaporation stages.

Systems and methods for implementing ejector refrigeration cycles with cascaded evaporation stages that utilize a pump to optimize operation of the ejector and eliminate the need for a compressor between the evaporation stages.

A refrigerant amount inference apparatus infers a refrigerant amount in an air conditioner in which a compressor, a heat source side heat exchanger, a supercooling heat exchanger, a pressure reducing valve, and a use side heat exchanger are connected to piping. The supercooling heat exchanger exchanges heat between refrigerant that passes through a valve provided in a bypass circuit and refrigerant in a mainstream circuit. The refrigerant amount inference apparatus includes an acquiring unit that acquires a state of refrigerant in first piping provided between the pressure reducing valve and the supercooling heat exchanger and an operation amount related to the state of the refrigerant in the first piping, and a training unit that performs training by associating the state of the refrigerant in the first piping and the operation amount related to the state of the refrigerant in the first piping with a refrigerant amount.

An air conditioner is provided with a refrigerant circuit that has a first refrigerant path to which a compressor, a first utilization-side heat exchanger, a first expansion valve, and a heat source-side heat exchanger are connected in order. A control unit controls the compressor and the first expansion valve. When the control unit receives a request for high-temperature air that temporarily increases the temperature of the hot air blown out through the first utilization-side heat exchanger, the control unit changes the control of the first expansion valve so that the temperature of a refrigerant that flows through the first utilization-side heat exchanger increases.