2303results about "Gas cycle refrigeration machines" patented technology

Methods and systems are provided for cooling an object with a cryogen having a critical point defined by a critical-point pressure and a critical-point temperature. A pressure of the cryogen is raised above a pressure value determined to provide the cryogen at a reduced molar volume that prevents vapor lock. Thereafter, the cryogen is placed in thermal communication with the object to increase a temperature of the cryogen along a thermodynamic path that maintains the pressure greater than the critical-point pressure for a duration that the cryogen and object are in thermal communication.

A reciprocating gas compressor is described operating according to an extended cycle of 4,6 or more strokes, wherein the first two strokes are sequential induction and compression strokes using a low pressure gas as working fluid and compressing it to a high pressure gas, and the remaining strokes are pairs of sequential filling and emptying strokes using more of the low pressure gas as heat transfer fluid for transferring heat from inside the gas compressor to outside the gas compressor. The gas compressor also contains an in-cylinder heat regenerator for absorbing heat from the compressed gas and releasing heat to the heat transfer fluid thus achieving near-isothermal compression. Using parallel principles, a reciprocating gas expander is also described for achieving near-isothermal expansion. Also described are reciprocating machines using the near-isothermal gas compressor and near-isothermal gas expander in combination according to the Ericsson heat engine cycle, the Stirling heat engine cycle and the Stirling refrigeration cycle.

An accumulator for an air-conditioning (refrigeration or heat pump) system is designed to reduce flooding due to greater effective internal volume while at the same time incorporating an internal heat exchanger for better system performance, and providing better evaporation and controlled thermal properties. The accumulator embodies an outer housing that co-axially surrounds an inner liner. The inlet directs the refrigerant into the inner volume formed by the liner, wherein the liquid refrigerant and compressor oil are contained and insulated from the wall of the outer housing. A heat exchanger is arranged in the annular space between the outer housing and the inner liner and circulates a flow of condensate therethrough before delivering it to the expansion device. In this way the condensate is cooled for higher performance and at the same time refrigerant passing out of the accumulator is vaporized more completely.

A first evaporator evaporates refrigerant, which is outputted from an ejector. A refrigerant outlet of the first evaporator is connected to a suction inlet of a compressor, which is connected to a radiator. A branched passage branches a flow of the refrigerant at a corresponding branching point located between the radiator and the ejector. The branched passage conducts the branched flow of the refrigerant to a suction inlet of the ejector. A flow rate control valve is arranged in the branched passage between a radiator and an ejector on a downstream side of the radiator to depressurize refrigerant outputted from the radiator. A second evaporator is arranged in the first branched passage.

A thermal storage container is coupled to a pump for circulating cooled liquid from the thermal storage container in at least one of two circuits. One circuit includes a heat exchanger coupled to the fresh food evaporator for assisting in cooling the fresh food section of the refrigerator or for chilling the liquid. Another circuit includes a sub-cooler between the compressor and condenser for cooling the hot gas output from the compressor before entering the condenser, thereby increasing the efficiency of the system. A three-way valve is coupled from the output pump to couple the stored coolant selectively to one or the other or both of the coolant circuits.

An ejector cycle system with a refrigerant cycle through which refrigerant flows includes an ejector disposed downstream of a radiator, a first evaporator that evaporates refrigerant flowing out of the ejector, a throttling unit located in a branch passage and depressurizes refrigerant to adjust a flow rate of refrigerant, and a second evaporator located downstream of the throttling unit. In the ejector cycle system, a flow ratio adjusting means adjusts a flow ratio between a first refrigerant flow amount depressurized and expanded in a nozzle portion of the ejector and a second refrigerant flow amount drawn into a refrigerant suction port of the ejector, based on a physical quantity related to at least one of a state of refrigerant in the refrigerant cycle, a temperature of a space to be cooled by the first and second evaporators, and an ambient temperature of the space.

A refrigerating system, using CO2 as a refrigerant, for an air conditioner for an automobile. A pressure at the outlet of the heat emitter 2 is controlled to a target value in accordance with the temperature of the refrigerant at the outlet of the heat emitter for obtaining an operation of the refrigerating system along the optimum control line eta max. A pressure reducer 4 and a cooler 5 are provided on a branched passageway 28 branched from a refrigerant recirculating passageway 27 for injection. The cooler 5 is for obtaining a heat exchange between a flow of the refrigerant on the branched passageway 28 after being cooled by the pressure reducer and a flow of the refrigerant on the main passageway 27, thereby cooling the refrigerant directed to the evaporator. In a second aspect of the invention, a means is provided for increasing a target value of the pressure at the pressure reducer when a thermal load of the refrigerating system is high. In a third aspect, a series of pressure reducers are arranged on the main recirculating passageway. The second stage pressure reducer is controlled so as to obtain a desired value of degree of super heating at the inlet of the compressor.

A GM type displacer has an elastomer "O" ring at the warm end to absorb impact energy when the displacer reaches the bottom of the stroke before it would hit the cylinder end cap. When the displacer reaches the top of its stroke, before the displacer would hit the internal mechanism of the expander, another elastomer "O" ring absorbs the kinetic energy of the displacer. Both absorbers are at or near ambient temperature.

The electrode temperature control device in a processing apparatus 100 includes a freezing circuit 110 comprising a compressor 148, a condenser 142, an expansion valve 150 and an evaporator 108 with the evaporator disposed inside a lower electrode 106. This electrode temperature control device does not require components such as a coolant tank for storing the coolant, a pump for supplying the coolant to the processing apparatus, a heater for adjusting the temperature of the coolant and a heat exchanger for exchanging heat between a primary coolant and a secondary coolant. Thus, the production cost can be lowered, a reduction in installation area through miniaturization of the apparatus is achieved and more efficient use of energy is achieved as well. In addition, by using CO2 as the coolant, the GWP value can be reduced to approximately {fraction (1 / 8000)} to {fraction (1 / 7000)} that of Freon.

A first evaporator evaporates refrigerant, which is outputted from an ejector. A refrigerant outlet of the first evaporator is connected to a suction inlet of a compressor, which is connected to a radiator. A branched passage branches a flow of the refrigerant at a corresponding branching point located between the radiator and the ejector. The branched passage conducts the branched flow of the refrigerant to a suction inlet of the ejector. A flow rate control valve is arranged in the branched passage between a radiator and an ejector on a downstream side of the radiator to depressurize refrigerant outputted from the radiator. A second evaporator is arranged in the first branched passage.

A brazed plate heat exchanger (30) is provided for transferring heat between a first fluid (32) and a second fluid (34), with the first fluid (32) being pressurized to a relatively high pressure. The heat exchanger includes plate pairs (41), with each pair (41) defining a plurality of flow channels (56) for the first fluid (32). Each of the flow channels (56) has a hydraulic diameter less than 1 mm. Reinforcements (62) are provided between each of the plate pairs (41) and are aligned with inlet and outlet openings (46,48) to define inlet and outlet manifolds (50,52) for the first fluid (32).

Embodiments of transport refrigeration systems, apparatus, and / or methods for the same can provide exemplary verification for operating characteristics thereof. In one embodiment, a calculated compressor mid stage pressure can be verified using a prescribed relationship to other transport refrigeration system characteristics.

By studying or storing refrigerating cycle characteristics of an air conditioning apparatus at the normal time and comparing them with refrigerating cycle characteristics acquired from the air conditioning apparatus at the time of operation, it becomes possible to exactly and accurately diagnose normality or abnormality of the air conditioning apparatus under any installation conditions and environmental conditions, which eliminates operations of inputting a difference between apparatus model names, a piping length, a height difference, etc at the time of apparatus installation. Accordingly, it aims at shortening the time of judging normality or abnormality, and improving the operability. It is characterized by calculating and comparing a measured value (a value of liquid phase temperature efficiency εL(SC / dTc) calculated from temperature information) concerning an amount of a liquid phase part of the refrigerant in the high-pressure-side heat exchanger with a theoretical value (a value of liquid phase temperature efficiency εL(1−EXP(−NTUR)) calculated from the transfer unit number NTUR at refrigerant side).

A heat pump cycle device includes a compressor for drawing and compressing refrigerant, a first high-pressure heat exchanger located for heating a first fluid circulating in a first fluid circuit using high-pressure refrigerant discharged from the compressor, a second high-pressure heat exchanger for heating a second fluid circulating in a second fluid circuit using the high-pressure refrigerant flowing out of the first high-pressure heat exchanger, a first heating heat exchanger located to heat a third fluid using the first fluid, a second heating heat exchanger located to heat the third fluid using the second fluid, a decompression unit located to decompress the high-pressure refrigerant flowing out of the second high-pressure heat exchanger, and a low-pressure heat exchanger for evaporating low-pressure refrigerant decompressed by the decompression unit. Because the first and second high-pressure heat exchangers are located, cycle efficiency can be improved.

In an ejector cycle system, high-pressure side refrigerant is decompressed by an ejector in cooling operation for cooling a compartment, and is decompressed by a fixed restrictor in heating operation for heating the compartment. Therefore, in the heating operation, the pressure of refrigerant to be sucked into a compressor can be made lower, and the temperature of refrigerant discharged from the compressor is increased. Alternatively, in the cooling operation, a flow direction of refrigerant flowing through at least one of an exterior heat exchanger and an interior heat exchanger is identical to that in the heating operation.

It is an object of the present invention to provide a refrigerator which is able to improve the efficiency of the refrigerating cycle while avoiding causing the structure of the refrigerator to be complicated, and avoiding a cost increase. Refrigerator 30 includes a refrigerating cycle device 20 having a compressor 1, a radiator 2 connected to a discharge side of the compressor 1, a first expansion valve 31 connected to an exit side of the radiator 2, a gas-liquid separator 33 for separating a refrigerant, which is in a mixed gas-liquid state by being decompressed by the first expansion valve 31, into a gas refrigerant and a liquid refrigerant, a heat absorber 14 into which the liquid refrigerant discharged from the gas-liquid separator 33 flows, and a refrigerant pipe 6D for delivering the gas refrigerant discharged from the gas-liquid separator 33 into the middle pressure portion of the compressor 1; an outer case 40; an inner case 39; and a heat insulating material. The gas-liquid separator 33 is arranged in the heat insulating material 47.

A refrigerant vapor compression system includes a refrigerant-to-refrigerant heat exchanger economizer and a flash tank disposed in series refrigerant flow relationship in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve is interdisposed in the refrigerant circuit upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve is interdisposed in the refrigerant circuit upstream of the flash tank. The flash tank functions as a refrigerant charge storage reservoir wherein refrigerant expanded from a supercritical pressure to subcritical pressure separates into liquid and vapor phases. A refrigerant vapor bypass line is provided to return refrigerant vapor from the flash tank to the refrigerant circuit downstream of the refrigerant heat absorption heat exchanger. The primary expansion valve and a flow control valve interdisposed in the refrigerant vapor bypass provide refrigerant charge management.

A refrigerant vapor compression system includes a flash tank disposed in series refrigerant flow relationship in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. A primary expansion valve is interdisposed in the refrigerant circuit upstream of the refrigerant heat absorption heat exchanger and a secondary expansion valve is interdisposed in the refrigerant circuit upstream of the flash tank. A refrigerant vapor line is provided to direct refrigerant vapor from the flash tank to an intermediate pressure stage of the compression process. A refrigerant-to-refrigerant heat exchanger operates to transfer heat from refrigerant flowing through the primary refrigerant circuit to refrigerant flowing through the refrigerant vapor line.

A method is provided for protecting a refrigerant vapor compression system during a standstill period following shutdown of the refrigerant vapor compression system. A method is provided for detecting a low refrigerant charge level in a refrigerant vapor compression system operating in a transcritical mode. A refrigerant vapor compression system is provided that includes a controller operative to perform a refrigerant charge detection method.

In a heat-pump water heater, a control unit has a heat-radiation determining means for determining a heat radiation from refrigerant to outside air in an air heat exchanger based on a water temperature flowing into a water heat exchanger, and the control unit selectively performs a general cycle operation and a bypass operation in accordance with a determination result of the heat-radiation determining means. That is, when the water temperature flowing into the water heat exchanger is lower than 60° C., the general cycle operation is performed. On the other hand, when the water temperature is equal to or higher than 60° C., the bypass operation is performed.

A thermoacoustic cooling system for cooling an object such as a microelectronic chip. Heat produced by the object is transferred to a thermoacoustic engine. The thermoacoustic engine may include a resonator defining a chamber. A stack may be positioned in the chamber with one side of the stack adjacent to the heat source, and the opposite side of the stack adjacent to air in the chamber having a relatively cooler temperature. One or more orifices may be formed in the resonator such that the acoustic power generated by the thermoacoustic engine creates a synthetic jet to circulate air and move the air away from the object being cooled. Thus, the heat produced by the object is used to power the thermoacoustic engine to thereby remove heat from the object. The thermoacoustic engine may use no moving parts and may require no external power source other than the object being cooled.

The present disclosure details a thermoacoustic driven compressor having a pressurized housing, which contains within a thermoacoustic engine and a working gas, coupled to a positive displacement reciprocating compressor. The thermoacoustic driven compressor generates scalable compressed air from a given heat source.

A method and apparatus for minimizing the amplitude of mechanical vibrations of a mechanical apparatus including a linear, freely reciprocating, prime mover coupled to and driving a reciprocating mass of a driven machine in reciprocation at a driving frequency. The coupled prime mover and driven machine have a spring applying a force upon the reciprocating mass to form a resonant main system having a main system resonant frequency of reciprocation. A driving frequency range over which the driven machine operates at an acceptable efficiency of operation is determined and stored. A parameter of the operation of the mechanical apparatus, such as the amplitude of vibrations or an operating temperature, is sensed and the prime mover is driven in response to the sensed parameter at a driving frequency that is offset from the main system resonant frequency of reciprocation, is within the driving frequency range of acceptable efficiency of operation and reduces or minimizes the amplitude of mechanical vibration of the mechanical apparatus under existing operating conditions.

A thermoacoustic refrigerator having a relatively small size which utilizes one or more piezoelectric drivers to generate high frequency sound within a resonator at a frequency of between about 4000 Hz and ultrasonic frequencies. The interaction of the high frequency sound with one or more stacks create a temperature gradient across the stack which is conducted through a pair of heat exchangers located on opposite sides of each stack. The stack is comprised of an open-celled material that allows axial, radial, and azimuthal resonance modes of the resonator within the stack resulting in enhanced cooling power of the thermoacoustic refrigerator.

In a hot-water supply system with a heat pump cycle, a control unit controls operation of an expansion valve based on a temperature difference between a refrigerant temperature at an outlet side of a refrigerant passage in a water heat exchanger and a water temperature at an inlet side of a water passage in the water heat exchanger. When the expansion valve is controlled in a direction increasing a valve opening degree, the control unit sets an upper limit opening degree of the expansion valve, for obtaining a refrigerant pressure corresponding to a target hot-water temperature, and controls the expansion valve in an opening degree range smaller than the upper limit opening degree.

In an ejector cycle having an ejector for decompressing refrigerant, a check valve is disposed in an oil return passage through which refrigerant including a lubrication oil is introduced from a refrigerant outlet side of an evaporator to a refrigerant suction side of a compressor while bypassing the ejector. When the lubrication oil amount staying in the evaporator reduces, the check valve is automatically closed, and a normal operation mode of the ejector cycle is automatically set. On the contrary, when a large amount of lubrication oil stays in the evaporator, the check valve is automatically opened, and an oil return mode is automatically set. Therefore, the lubrication oil staying in the evaporator can be controlled equal to or lower than a predetermined amount, thereby effectively returning the lubrication oil to the compressor.

A refrigerant vapor compression system includes a flash tank disposed in the refrigerant circuit intermediate a refrigerant heat rejection heat exchanger and a refrigerant heat absorption heat exchanger. The flash tank has a shell defining an interior volume having an upper chamber, a lower chamber and a middle chamber. A first fluid passage establishes fluid communication between the middle chamber and the upper chamber and a second fluid passage establishing fluid communication between the middle chamber and the lower chamber. An inlet port opens to the middle chamber. A first outlet port opens to the upper chamber and a second outlet port opens to the lower chamber.

Reversible vapor compression system including a compressor (1), an interior heat exchanger (2), an expansion device (6) and an exterior heat exchanger (3) connected by means of conduits in an operable relationship to form an integral main circuit. A first means is provided in the main circuit between the compressor and the interior heat exchanger, and a second means is provided on the opposite side of the main circuit between the interior and exterior heat exchangers to enable reversing of the system from cooling mode to heat pump mode and vice versa.

An heat pump drying machine has a normal dry mode (e.g., compression ratio is equal to or greater than 3) for operating a compressor at a predetermined dry operation frequency and an energy saving dry mode (e.g., compression ratio is equal to or greater than 2.3 and is less than 3) for operating the compressor at an energy saving operation frequency that is lower than the dry operation frequency. A control device is provided to control an operation frequency of the compressor 5 so that the two dry operation modes are switched to each other. The control device can execute the control for increasing the operation frequency of the compressor to the dry operation frequency during the operation of the energy saving dry mode.