System with a compressor and with a consumer in a motor vehicle

A system has a compressor and a consumer which are coupled to a drivetrain and extract energy through the drivetrain. The consumer is suitable for varying an absorption of power, which is made available to it by the drivetrain, as a function of a power which is required for compressor operation and which is supplied from the drivetrain to the compressor. A pump has at least one pump chamber which generates a pumping power during pumping operation. The pump additionally has at least one pump chamber which generates no pumping power or a reduced pumping power during pumping operation.