FIELD

This disclosure relates generally to a vapor compression system. More specifically, the disclosure relates to controlling a volume ratio of a compressor for a vapor compression system such as, but not limited to, a heating, ventilation, air conditioning, and refrigeration (HVACR) system.

BACKGROUND

One type of compressor for a vapor compression system is generally referred to as a screw compressor. A screw compressor generally includes one or more rotors (e.g., one or more rotary screws). Typically, a screw compressor includes a pair of rotors (e.g., two rotary screws) which rotate relative to each other to compress a working fluid such as, but not limited to, a refrigerant or the like.

SUMMARY

This disclosure relates generally to a vapor compression system. More specifically, the disclosure relates to controlling a volume ratio of a compressor for a vapor compression system such as, but not limited to, a heating, ventilation, air conditioning, and refrigeration (HVACR) system.

In an embodiment, the compressor is a screw compressor. In an embodiment, the screw compressor is used in an HVACR system to compress a working fluid (e.g., a heat transfer fluid such as, but not limited to, a refrigerant or the like).

In an embodiment, the screw compressor is actuated by a variable frequency drive (VFD).

In an embodiment, the screw compressor has a variable volume ratio. In an embodiment, the screw compressor is operable at a first volume ratio and at a second volume ratio. In an embodiment, the first volume ratio is relatively lower than the second volume ratio. In an embodiment, the volume ratio is controllable based on a valve assembly disposed on a suction side of the screw compressor.

In an embodiment, the valve assembly can be used to vary a location of the suction port.

A screw compressor is disclosed. The screw compressor includes a suction inlet that receives a working fluid to be compressed. A compression mechanism is fluidly connected to the suction inlet that compresses the working fluid. A discharge outlet is fluidly connected to the compression mechanism that outputs the working fluid following compression by the compression mechanism. A valve assembly is configured to vary a location at which the compression mechanism compresses the working fluid, the valve assembly being disposed to modify a suction location of the screw compressor.

A method of modifying a volume ratio of a screw compressor is disclosed. The method includes determining a discharge pressure of the screw compressor; and modifying a location of a suction port of the screw compressor in response to the discharge pressure of the screw compressor as determined. At a relatively higher discharge pressure a suction port is disposed so that compression begins relatively sooner than at a relatively lower discharge pressure.

A refrigerant circuit is disclosed. The refrigerant circuit includes a compressor, a condenser, an expansion device (e.g. valve, orifice, or the like), and an evaporator fluidly connected. The compressor includes a suction inlet that receives a working fluid to be compressed. A compression mechanism is fluidly connected to the suction inlet that compresses the working fluid. A discharge outlet is fluidly connected to the compression mechanism that outputs the working fluid following compression by the compression mechanism. A valve assembly is configured to vary a location at which the compression mechanism compresses the working fluid, the valve assembly being disposed to modify a suction location of the screw compressor.

