A scroll-type refrigerant compressor having a movable scroll unit and a stationary scroll unit which has a fixed stationary end plate in which a plurality of bypass ports and a discharge port are formed through which the refrigerant compressed in the pockets formed between the movable and stationary scroll units is discharged via check valves covering the bypass ports and the discharge port and preventing a reverse flow of the discharged refrigerant into the pockets. The compressor further having a suction port fluidly connected to an evaporator of an air-conditioning system, a delivery port fluidly connected to a condenser of the air-conditioning system, and a fluid channel for providing a fluid communication between the suction and delivery ports via a solenoid-operated valve for blocking and unblocking the fluid channel. The compressor can be switched from the ordinary 100% capacity to 0% capacity and vice versa.