A centrifugal compressor for HVAC application includes a rotary component rotatable about an axis, a static component, and a brush seal fixed to one of the static component and the rotary component. The brush seal includes bristles that contact the other of the static component and the rotary component.

A centrifugal compressor for HVAC application includes a rotary component rotatable about an axis, a static component, and a brush seal fixed to one of the static component and the rotary component. The brush seal includes bristles that contact the other of the static component and the rotary component.

A gas refrigerating machine having: an input for gas to be cooled; a recuperator; a compressor having a compressor input, the compressor input being coupled to a first recuperator output; a heat exchanger; a turbine; and a gas output, wherein the recuperator is rotationally symmetrical, wherein an axis of symmetry of the recuperator coincides with an axis of the compressor, or an axis of the turbine, or an axis of a rotor of a drive motor, or an axis of the gas output, or an axis of the input, or an axis of a suction region basically or within manufacturing tolerances.

A gas refrigerating machine having: an input for gas to be cooled; a recuperator; a compressor having a compressor input coupled to a first recuperator output; a heat exchanger; a turbine; and a gas output, wherein the gas refrigerating machine has a housing in the wall of which the input for gas to be cooled is located and in the wall of which the gas output is located, the recuperator, the compressor, the turbine and the heat exchanger arranged in the housing, and the gas refrigerating machine formed as an open system, wherein the input for gas is located in a region to be cooled and the gas output is located in the region to be cooled to suck warm gas from the region to be cooled via the input for gas and to discharge cold gas into the region to be cooled via the gas output.

An expander and motor-compressor unit is disclosed. The unit includes a casing and an electric motor arranged in the casing. A compressor is arranged in the casing and drivingly coupled to the electric motor through a central shaft. Furthermore, a turbo-expander is arranged for rotation in the casing and is drivingly coupled to the electric motor and to the compressor through the central shaft.

An expander and motor-compressor unit is disclosed. The unit includes a casing and an electric motor arranged in the casing. A compressor is arranged in the casing and drivingly coupled to the electric motor through a central shaft. Furthermore, a turbo-expander is arranged for rotation in the casing and is drivingly coupled to the electric motor and to the compressor through the central shaft.

A reverse compression cycle machine includes an evaporator, a compressor and a condenser arranged in series along a path of a working fluid in the machine, further including a boundary layer turbine placed between the condenser and the evaporator. The turbine includes a set of power disks mounted on a shaft which rotates inside a volume of a rotor casing, an inlet opening for introducing a working fluid in a stator volume, a stator nozzle, which accelerates the flow in a direction that is tangential to the power disks, and a discharge of a working fluid. The rotor casing includes a drain of a liquid fraction of the working fluid from the peripheral part of the power disks in order to avoid its concentration in the peripheral part of the volume of the rotor casing.

A reverse compression cycle machine includes an evaporator, a compressor and a condenser arranged in series along a path of a working fluid in the machine, further including a boundary layer turbine placed between the condenser and the evaporator. The turbine includes a set of power disks mounted on a shaft which rotates inside a volume of a rotor casing, an inlet opening for introducing a working fluid in a stator volume, a stator nozzle, which accelerates the flow in a direction that is tangential to the power disks, and a discharge of a working fluid. The rotor casing includes a drain of a liquid fraction of the working fluid from the peripheral part of the power disks in order to avoid its concentration in the peripheral part of the volume of the rotor casing.

The invention relates to a method for cooling a superconducting cable (1) using a coolant containing or consisting of liquid nitrogen, wherein at least a part of the coolant is subjected to a subcooling step and thereafter brought into thermal contact with the superconducting cable (1) in a cooling cycle, wherein said subcooling step is at least in part performed using a refrigerant provided in a Brayton process in which at least a part of the refrigerant is cooled and heated in a main heat exchanger (11). According to the present invention, a part of the coolant is withdrawn from the cooling cycle and heated in the same main heat exchanger (11) in which at least a part of the refrigerant is cooled and heated in the Brayton process. A corresponding device and a corresponding system are also part of the present invention.

A heat-driven refrigeration/heat-pump system includes at least one vapor expansion stage and at least one vapor compression stage, a condenser, and an evaporator, while the power consumption of the compression stages is fully supplied by the power output of the expansion stages. In the system, a vapor absorber/generator unit is adopted, such that at least one expansion stage is fed by the vapor from the generator, and at least one power stage; compression or expansion, delivers its output stream to the absorber instead of to the condenser. In the new arrangement the expansion stages produce surplus power, facilitating a supplementary refrigeration loop between the evaporator and the condenser to which there is no direct expense of heat from the generator, thereby improving the overall performance of the system.