Systems and methods for compressor unloading detection are provided and include a compressor having a compression mechanism. A controller determines a predicted discharge temperature of the compressor, receives an actual discharge temperature of the compressor, and compares the predicted discharge temperature with the actual discharge temperature. The controller also compares a speed of the compressor with a speed threshold and detects unloading of the compression mechanism based on the comparison of the predicted discharge temperature with the actual discharge temperature and based on the comparison of the speed of the compressor with the speed threshold. The controller performs at least one of generating an alert and a remediating action in response to detecting the unloading of the compression mechanism.

A control system for controlling an output for at least one compressor includes a control unit that receives an indoor set point and an outdoor ambient temperature. The control unit determines a load request based on the indoor set point and the outdoor ambient temperature without considering an indoor room temperature. The at least one compressor receives control commands from the control unit based on the load request.

Systems and methods for scroll unloading detection are provided and include a scroll compressor having a scroll compression mechanism. A controller determines a predicted discharge temperature of the scroll compressor, receives an actual discharge temperature of the scroll compressor, and compares the predicted discharge temperature with the actual discharge temperature. The controller also compares a speed of the scroll compressor with a speed threshold and detects unloading of the scroll compression mechanism based on the comparison of the predicted discharge temperature with the actual discharge temperature and based on the comparison of the speed of the scroll compressor with the speed threshold. The controller performs at least one of generating an alert and a remediating action in response to detecting the unloading of the scroll compression mechanism.

A compressor uses a refrigerant containing R1123 (1,1,2-trifluoroethylene) as a working fluid, and uses a polyol ester oil as a compressor lubricating oil. In addition, a fixed scroll and a revolving scroll each having a spiral lap rising from an end plate, and a compression chamber which is formed by meshing the fixed scroll and the revolving scroll, are provided. In addition, a discharge hole which is provided at a center position of the end plate of the fixed scroll, and is open to a discharge chamber, a bypass hole which is provided in the end plate of the fixed scroll, and communicates with the compression chamber and the discharge chamber at a timing different from a timing at which the compression chamber communicates with the discharge hole, and a check valve which is provided in the bypass hole, and allows a flow from the compression chamber side to the discharge chamber side.

This disclosure relates to a centrifugal compressor. In a first example, the compressor includes a first impeller provided in a main refrigerant flow path, a second impeller provided in the main refrigerant flow path downstream of the first impeller, and a recirculation flow path. In the first example, the recirculation flow path is provided between a first location and a second location along the main refrigerant flow path. The first location is downstream of the second location, and the second location is downstream of the first impeller. In a second example, the compressor includes an impeller provided in a main refrigerant flow path, and a recirculation flow path provided between a first location and a second location along the main refrigerant flow path. In the second example, the recirculation flow path includes a recirculation volute. Further disclosed is a method for operating a centrifugal compressor.

Control systems and methods for increasing efficiency of a compressor while the compressor capacity exceeds compressor load, by using a mechanical unloader such as a slide valve to reduce the internal volume ratio of the compressor and allow a more efficient speed to be maintained by a variable frequency drive (VFD) while reducing the compressor capacity based on the load. Control systems include the VFD, a controller for the VFD and the mechanical unloader, and temperature sensors. Compressor embodiments further include one or more compressors and mechanical unloaders operated by the control systems.

A device under test cooling system has a refrigerant line and a fluid line extending through a plurality of successively arranged heat exchangers. A digital scroll compressor has an intake for providing the refrigerant mixture to the compressor and a discharge connecting the compressor to the refrigerant line to provide the refrigerant mixture to the heat exchangers. The compressor includes a plurality of scroll elements between the intake and the discharge for compressing the refrigerant mixture. The compressor includes a valve configured to separate the scroll elements when in an open position to allow refrigerant to flow freely between the intake and the discharge. When the valve is in a closed position, the scroll elements compress the refrigerant. A controller is configured to switch the valve between an open and closed position based on a set duty cycle.

A refrigeration cycle device includes a compressor. The compressor includes a casing, a driving unit disposed in the casing, a compression unit coupled to the driving unit and configured to compress a refrigerant, and a valve configured to control a flow of the refrigerant in the casing. The valve includes a valve chamber including a main flow path in which the refrigerant is to flow, the main flow path including a refrigerant inlet and a refrigerant outlet. The valve also includes a floating body disposed in the valve chamber to open or close the main flow path, and a bypass flow path formed in the valve chamber and which is to be opened or closed by the floating body. When the driving unit is stopped and the bypass flow path is opened by the floating body, the refrigerant is to be detoured to the bypass flow path.

A compressor uses a refrigerant containing R1123 (1,1,2-trifluoroethylene) as a working fluid, and uses a polyvinyl ether oil as a compressor lubricating oil. In addition, a fixed scroll (12) and a revolving scroll (13) each having a spiral lap rising from an end plate, and a compression chamber (15) which is formed by meshing the fixed scroll (12) and the revolving scroll (13), are provided. In addition, a discharge hole (18) which is provided at a center position of the end plate of the fixed scroll (12), and is open to a discharge chamber (31), a bypass hole (68) which is provided in the end plate of the fixed scroll (12), and communicates with the compression chamber (15) and the discharge chamber (31) at a timing different from a timing at which the compression chamber (15) communicates with the discharge hole (18), and a check valve which is provided in the bypass hole (68), and allows a flow from the compression chamber (15) side to the discharge chamber (31) side.

An intermediate discharge port in a scroll compressor and a method for controlling part-load efficiency of a scroll compressor are disclosed. The compressor includes a compressor housing; a non-orbiting scroll member and an orbiting scroll member forming a compression chamber; a discharge port for receiving a compressed fluid; and an intermediate discharge port fluidly connected between the compression chamber and the discharge port, the intermediate discharge port including a sealing member, fluid flow being prevented between the compression chamber and the discharge port through the intermediate discharge port when in a flow-blocked state, and fluid flow being enabled between the compression chamber and the discharge port through the intermediate discharge port when in a flow-permitted state.