Abstract: A refrigerant compressor group for a refrigeration system, comprising at least two piston compressors that operate in parallel between a common low-pressure connector and a common high-pressure connector, wherein, for the purpose of adjusting it to different requirements, it is provided, in a refrigerant compressor group, for a variable overall mass flow throughput in the refrigerant compressor group to be 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 cl

Abstract: The invention relates to an expansion unit for installation in a refrigerant circuit, including an expansion system having an subcooling unit for subcooling a mass flow of a refrigerant that is supplied to the expansion unit, having an expansion/compression unit including an expander stage and a compressor stage, having a branching point that splits off a subcooling mass flow from a total mass flow supplied to the expansion unit and that is connected to a supply conduit that guides the subcooling mass flow to an inlet of the subcooling unit, having an expansion member that expands the subcooling mass flow to a subcooling pressure, having a connection conduit that supplies the subcooling mass flow exiting from the subcooling unit to the compression stage, which for its part compresses the subcooling mass flow to a return high pressure, and having an electrically operated controller that detects an ambient temperature and/or a temperature of the mass flow of refrigerant that is supplied to the expansion unit an

Abstract: A refrigeration system is of the type that includes a refrigerant compressor unit which compresses normal refrigerating mass flow and a parallel compressor. The parallel compressor in a parallel compression mode of operation of the refrigerant circuit, sucks in refrigerant from the intermediate pressure accumulator and compresses it to high pressure. It is proposed that, in order to increase efficiency, the power of the parallel compressor is controlled by a control system. The control system determines at least one reference variable representing a load state of the refrigerant circuit, that determines a set intermediate pressure value on the basis of the at least one reference variable at least in a parallel compression mode of operation, and that regulates the intermediate pressure in accordance with the set intermediate pressure value at least in the parallel compression mode of operation.

Abstract: The invention relates to an expansion unit for installation in a refrigerant circuit, including an expansion system having an subcooling unit for subcooling a mass flow of a refrigerant that is supplied to the expansion unit, having an expansion/compression unit including an expander stage and a compressor stage, having a branching point that splits off a subcooling mass flow from a total mass flow supplied to the expansion unit and that is connected to a supply conduit that guides the subcooling mass flow to an inlet of the subcooling unit, having an expansion member that expands the subcooling mass flow to a subcooling pressure, having a connection conduit that supplies the subcooling mass flow exiting from the subcooling unit to the compression stage, which for its part compresses the subcooling mass flow to a return high pressure, and having an electrically operated controller that detects an ambient temperature and/or a temperature of the mass flow of refrigerant that is supplied to the expansion unit an

Abstract: In a refrigeration system comprising a refrigerant circuit, a heat exchanger, an expansion element which, in the active state, cools the entire mass flow of the refrigerant by expansion and thereby produces a main mass flow consisting of liquid refrigerant and an auxiliary mass flow consisting of gaseous refrigerant which enter an intermediate pressure accumulator, at least one normal refrigerating stage which expands a normal refrigerating mass flow in at least one normal refrigerating expansion unit to a low pressure and thereby makes refrigerating capacity available for normal refrigerating purposes, a refrigerant compressor unit which compresses the normal refrigerating mass flow from low pressure to high pressure, and a parallel compressor which, in a parallel compression mode of operation of the refrigerant circuit, sucks in refrigerant from the intermediate pressure accumulator and compresses it to high pressure, it is proposed that, in order to increase the efficiency, the power of the parallel compre

Abstract: In order to improve a refrigerating plant, comprising a refrigerant circuit, with a high-side refrigerant-cooling heat exchanger, with an expansion cooling device, with a reservoir for the main mass flow, with at least one normal cooling stage, with an intense cooling stage, which removes an overall intense cooling mass flow from the reservoir, and with at least one refrigerant compressor unit, which is disposed in the refrigerant circuit, in such a way that it has a better efficiency, it is proposed that the intense cooling stage has for further cooling of the overall intense cooling mass flow an intense cooling expansion cooling device, which in the active state cools the overall intense cooling mass flow and thereby produces a main intense cooling mass flow, which is fed to the intense cooling expansion element, and an additional intense cooling mass flow.

Abstract: In order to improve a refrigerating plant, comprising a refrigerant circuit, with a high-side refrigerant-cooling heat exchanger, with an expansion cooling device, with a reservoir for the main mass flow, with at least one normal cooling stage, with an intense cooling stage, which removes an overall intense cooling mass flow from the reservoir, and with at least one refrigerant compressor unit, which is disposed in the refrigerant circuit, in such a way that it has a better efficiency, it is proposed that the intense cooling stage has for further cooling of the overall intense cooling mass flow an intense cooling expansion cooling device, which in the active state cools the overall intense cooling mass flow and thereby produces a main intense cooling mass flow, which is fed to the intense cooling expansion element, and an additional intense cooling mass flow.