A system for controlling a capacity of a compressor includes a motor of the compressor including a main winding connected at a connection point to an auxiliary winding and a drive configured to control a speed of the motor. The system includes a first switch configured to selectively connect the main winding to either a first line voltage or a first output of the drive, a second switch configured to selectively connect the connection point to either a second line voltage or a second output of the drive, and a third switch configured to selectively connect the auxiliary winding to either a capacitor or a third output of the drive. The system includes a solenoid valve configured to selectively either operate in a first capacity or a second capacity. The system includes a control module configured to control the drive, the first switch, the second switch, and the third switch.

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 refrigerant control system for controlling a first refrigerant flowing through a first circulation passage connected to a compression unit, including a storing unit which stores a first refrigerant, a first sub-pipe which is connected to an outlet side pipe, a second sub-pipe which is connected to an inlet side pipe, a first opening/closing valve which is provided in the first sub-pipe and is capable of switching whether to flow the first refrigerant in the outlet side pipe to the storing unit, a second opening/closing valve which is provided in the second sub-pipe and is capable of switching whether to flow the first refrigerant in the storing unit to the inlet side pipe, and an opening/closing control unit which controls an opening/closing state of the first opening/closing valve and the second opening/closing valve on the basis of a setting temperature of a second refrigerant set according to a predetermined method.

A method controls the level of liquid within an evaporator of a flooded-type chiller without level sensors. The flooded-type chiller includes at least one compressor, a condenser, an expansion valve and an evaporator. A number of sensors positioned in the system measures a number of first parameter information values. A controller calculates a number of second parameter information values based on the measured first parameter information values and further determines a virtual refrigerant level as a control signal based on the second parameter information values. Based on the determined virtual refrigerant level, the controller opens, closes or holds the expansion valve with respect to a dead zone for maintaining a pre-defined target refrigerant level so as to provide the desired refrigerant level and oil in the evaporator.

A refrigerant control system for controlling a first refrigerant flowing through a first circulation passage connected to a compression unit, including a storing unit which stores a first refrigerant, a first sub-pipe which is connected to an outlet side pipe, a second sub-pipe which is connected to an inlet side pipe, a first opening/closing valve which is provided in the first sub-pipe and is capable of switching whether to flow the first refrigerant in the outlet side pipe to the storing unit, a second opening/closing valve which is provided in the second sub-pipe and is capable of switching whether to flow the first refrigerant in the storing unit to the inlet side pipe, and an opening/closing control unit which controls an opening/closing state of the first opening/closing valve and the second opening/closing valve on the basis of a setting temperature of a second refrigerant set according to a predetermined method.

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 system for controlling a capacity of a compressor includes a motor of the compressor including a main winding connected at a connection point to an auxiliary winding and a drive configured to control a speed of the motor. The system includes a first switch configured to selectively connect the main winding to either a first line voltage or a first output of the drive, a second switch configured to selectively connect the connection point to either a second line voltage or a second output of the drive, and a third switch configured to selectively connect the auxiliary winding to either a capacitor or a third output of the drive. The system includes a solenoid valve configured to selectively either operate in a first capacity or a second capacity. The system includes a control module configured to control the drive, the first switch, the second switch, and the third switch.

A method of controlling a refrigeration system including a medium temperature refrigeration load and a low temperature refrigeration load. The method includes selectively bypassing refrigerant between a medium temperature suction group and a low temperature suction group via a bypass line using an electronic valve positioned in the bypass line. The method also includes controlling flow of refrigerant between the medium temperature suction group and the low temperature suction group via a controller communicatively coupled to the valve, and modulating the valve at any position between a closed position and a full open position to vary an amount of refrigerant flow between the medium temperature suction group and the low temperature suction group in response to determining, via the controller, one or both of a state of the medium temperature suction group and a state of the low temperature suction group.

In various implementations, a heat exchanger system may include one or more flow paths. At least one of the flow paths may be associated with more than one pass and/or fluid flow through the flow path may be restricted. A setting of the heat exchanger system may include associations between flow path(s) and/or pass(es). A setting for the heat exchanger system may be determined, and the heat exchanger system may be allowed to operate in the determined setting, in some implementations.

A refrigeration system includes a plurality of utilization units provided for one air conditioning target space, a refrigerant leakage sensor that detects a leakage of the refrigerant in a lower part of the air conditioning target space, and a control unit. In a case where the refrigerant leakage sensor detects the refrigerant leakage, the control unit performs detection standby control on the utilization units such that the supply of the refrigerant to utilization-side heat exchangers is temporarily stopped. In a case where the refrigerant leakage is detected based on the state quantity of the refrigerant corresponding to the utilization units under the detection standby control, the control unit stops the use of the utilization unit in which the refrigerant leakage has been detected.