Refrigerant compressor group

A refrigerant compressor group for a refrigeration system, comprising:

• at least two piston compressors that operate in parallel between a common low-pressure connector of which a low-pressure line leads to a heat exchanger on a low-pressure side and a common high-pressure connector, of which a high-pressure line leads to a heat exchanger on a high-pressure side are operable individually and each have an electric motor and cylinder units that are driven by the electric motor;
• wherein, in the refrigerant compressor group, an overall mass flow throughput in the refrigerant compressor group that is variable within the range from a minimum mass flow throughput to a maximum mass flow throughput is adjustable in that, in the case of at least one of the piston compressors, its mass flow throughput is adjustable by speed selection with the aid of a frequency converter for the electric motor, and in that, in the case of at least one of the piston compressors, its mass flow throughput is adjustable by cylinder selection, and in that an operating condition controller for the refrigerant compressor group is provided which, on the basis of a performance request signal of the refrigeration system that is transmitted to the operating condition controller, controls the overall mass flow throughput by open or closed-loop control by predetermining the cylinder selection and the speed selection;
• and
• wherein each of the at least two piston compressors includes at least one cylinder bank, and wherein activation and deactivation of each cylinder bank is performed with the aid of a mechanical performance control unit that is controlled by the operating condition controller, wherein the mechanical performance control unit connects the outlet chamber to the inlet chamber in the cylinder head for the purpose of activating or deactivating the at least one cylinder bank.