Converting compressor to variable VI compressor

A method of converting a fixed volume ratio screw compressor to a variable volume ratio screw compressor, comprising:

• providing a plurality of outlets that are fluidly communicable with a compression mechanism of the fixed volume ratio screw compressor and fluidly communicable with a discharge outlet of the fixed volume ratio screw compressor;
• and
• providing a slide piston assembly that determines which outlet of the plurality of outlets is fluidly connected with the compression mechanism and the discharge outlet,
• wherein the slide piston assembly is actuatable by a working fluid at a discharge pressure of the variable volume ratio screw compressor applied to a piston of the slide piston assembly downstream from the compression mechanism.

A refrigerant circuit, comprising:

• a compressor, a condenser, and an evaporator fluidly connected;
• the compressor including:
• a suction inlet that receives a working fluid to be compressed from the evaporator;
• a compression mechanism fluidly connected to the suction inlet that compresses the working fluid;
• a discharge outlet fluidly connected to the compression mechanism that outputs the working fluid to the condenser following compression by the compression mechanism;
• wherein the compression mechanism fluidly communicates with one or more outlets disposed at an intermediate location between the suction inlet and the discharge outlet, the one or more outlets being selectively fluidly connectable to the discharge outlet such that the working fluid can be provided from the one or more outlets to the discharge outlet,
• the one or more outlets are selectively fluidly connectable via a slide piston assembly, and
• the slide piston assembly is actuatable by the working fluid at a discharge pressure of the compressor applied to a piston of the slide piston assembly downstream of the compression mechanism.