A regenerator of a cryo-cooler uses helium both as a working gas and as a heat storage material. The regenerator includes cells whose exterior sides form flow channels through which the working gas flows. Each cell has connected first and second cavities enclosed by a heat-conductive cell wall. The cavities contain helium that is used to store heat. Each cells is shaped as a disk. The working gas flows both through the flow channels and around the regenerator so as to exchange heat with the helium in the cavities via the heat conducting cell wall. Each cell has a pressure-equalizing opening through the cell wall whose diameter is smaller than the thickness of the cell wall. The diameter of the pressure-equalizing opening is dimensioned to permit the pressure of the helium contained in the cell to change by a maximum of 20% during any working cycle of the cryo-cooler.

A thermoacoustic refrigerator includes at least one pair of pulse combustion tubes (10), preferably Rijke tubes, each tube (10) having a pair of spaced-apart Stirling engines (12), coupled together but with no separating membrane therebetween.

A cooling device (1) has a cryostat (2) and a cold head (3) of a cooling system (52), and additionally includes a pivot bearing (35), with which the cold head (3) is mounted on the cryostat (2) so as to be rotatable about a rotation axis (A). A connecting line (15) for a working gas of the cooling system (52) is connected to the cold head so that forces caused by the cooling system (52) act on the cold head via the connecting line (15) at a force application point (EP) in a force application direction (ER). The force application direction (ER) is inclined by no more than 40° with respect to the normal (N) of a lever plane (HE) which contains the rotation axis (A) and the force application point (EP).

The present invention provides a multi-stage double-acting traveling-wave thermoacoustic system, comprising three elementary units, each elementary unit comprises a linear motor and a thermoacoustic conversion device; the linear motor comprises a piston and a cylinder, the piston can perform a straight reciprocating motion in the cylinder; each thermoacoustic conversion device comprises a main heat exchanger and a heat regenerator connected in sequence, and the heat regenerator is of a ladder structure; a set of a non-normal-temperature heat exchanger, a thermal buffer tube and an auxiliary heat exchanger is connected at each ladder of the heat regenerator; and the main heat exchanger and the auxiliary heat exchanger of each thermoacoustic conversion device are connected to cylinder cavities of different linear motors respectively forming a loop structure for flow of a gas medium. The multi-stage double-acting traveling-wave thermoacoustic system can improve the working performance of the multi-stage double-acting traveling-wave thermoacoustic system.

An inertance tube for a pulse tube refrigerator which can be tuned to optimize performance. Apertures in the inertance tube fluidly communicate the inertance tube with a fluid reservoir. The effective length of the inertance tube is changed by alternatively closing or opening the apertures. Changing the effective length of the inertance tube causes a phase shift between the mass flow and pressure waves in the working gas which, in turn, changes the acoustic power. Controlling the phase angle improves Carnot efficiency. The cooling load capacity of the pulse tube refrigerator is a function of the acoustic power.

Disclosed is a thermoacoustic engine having: resonance pipes including a working gas; motors; and a branch pipe, where each of the motors has a regenerator, a heater, and a cooler, a temperature gradient is given between both ends of the regenerator to generate self-excited oscillation of the working gas, a channel cross-sectional area of the resonance pipe that is coupled to the heater is expanded by a same amplification factor of a work flow based on the self-excited oscillation or by an amplification factor within a range of ±30% of the amplification factor of the work flow to a channel cross-sectional area of a resonance pipe that is coupled to the cooler, and a channel cross-sectional area of the regenerator is set by 4 to 36 times of the channel cross-sectional area of the resonance pipe that is coupled to the cooler.

A double-inlet valve for a Gifford-McMahon (GM) type double-inlet pulse tube cryocooler system for providing cooling at cryogenic temperatures includes a fixed restrictor and a needle valve coupled to the fixed restrictor in parallel. The needle valve produces asymmetric flow. The combination of the fixed restrictor and the needle valve having an asymmetric flow provides improved alternating current (AC) flow characteristics and adjustability of direct current (DC) flow to increase the available cooling.

A rotary valve mechanism includes a valve stator having a stator recessed portion and a valve rotor having a rotor recessed portion. The rotor recessed portion is formed in the valve rotor such that a rotor-recessed-portion front edge line passes through a stator-recessed-portion front edge line and the rotor recessed portion fluidally communicates with the stator recessed portion at a first phase of rotary-valve-mechanism rotation, and a rotor-recessed-portion rear edge line passes through a stator-recessed-portion rear edge line and the rotor recessed portion is fluidally separated from the stator recessed portion at a second phase thereof, and a shape of the rotor-recessed-portion front edge line coincides with a shape of the stator-recessed-portion front edge line such that the rotor-recessed-portion front edge line overlaps the stator-recessed-portion front edge line at the first phase.

A water recovery device includes: an exhaust gas pipe that is connected to a combustion device; a water generation unit that generates water by cooling exhaust gas in the exhaust gas pipe to condense water vapor in the exhaust gas; and a water container that stores water generated by the water generation unit. The water generation unit includes: an acoustic-wave generator that generates acoustic waves by absorbing heat from the exhaust gas pipe and giving the heat to working fluid, which transmits acoustic waves by oscillating, to cause the working fluid to oscillate; a transmission pipe that is internally filled with the working fluid and transmits acoustic waves generated by the acoustic-wave generator; and a cold-heat generator that generates cold heat to supply the cold heat to the exhaust gas pipe by receiving acoustic waves transmitted through the transmission pipe and giving heat to the acoustic waves.

Systems and methods for improving the performance of dilution refrigeration systems are described. Electrostatic cryogenic cold traps employed in the helium circuit of a dilution refrigerator improve the removal efficiency of contaminants from the helium circuit. An ionization source ionizes at least a portion of a refrigerant that includes helium and number of contaminants. The ionized refrigerant passes through an electrostatic cryogenic cold trap that includes a number of surfaces at one or more temperatures along at least a portion of the fluid passage between the cold trap inlet and the cold trap outlet. A high voltage source coupled to the surfaces to causes a first plurality of surfaces to function as electrodes at a first potential and a second plurality of surfaces to function as electrodes at a second potential. As ionized contaminants release their charge on the electrodes, the contaminants bond to the electrodes.